《Java程序设计实例与操作》（丁永卫）目录

 　图书管理系统会因为图书的数量、种类、提供的操作等不同而具有不同的复杂度。基本信息的维护、图书借阅、归还及查询等操作通常是图书管理系统的基本功能。在规模较大、业务较多的图书馆还需要图书的库存管理、销售管理等更加复杂的功能。

12.1 系统详细设计

一、开发环境

 操作系统：Windows XP
 数据库系统：Access
 编程语言： Java 6.0
 开发工具：Eclipse 3.4

二、数据库设计

 　本例采用的数据库类型为Access，数据库名为“图书管理.mdb”，其中包含了3个表，分别是图书信息表book，读者信息表reader，借阅信息表borrow。

三、系统模块设计

 　（1）MainPro包：主要包括了登录程序、系统主程序、图书和读者信息维护程序、图书借阅管理程序，以及图书和读者信息查询程序等。

 　（2）PublicModule包：其中包含了一组供MainPro包中各类使用的公共类 。

12.2 公共模块设计

一、DbOp.java

 　该类用于完成基本的数据库操作，包括加载数据库驱动，创建数据库连接，执行Sql语句等。其中，其构造方法用于加载数据库驱动程序和创建数据库连接（即打开数据库）；
用于查询记录的方法为executeQuery()；
用于插入、删除、修改记录的方法为executeUpdate()；
用于关闭数据的方法为Close()。

// DbOp.java
package PublicModule;import java.sql.*;import javax.swing.JOptionPane;public class DbOp {// JDBC-ODBC驱动程序private static String driver = "sun.jdbc.odbc.JdbcOdbcDriver";// 数据库url路径private static String url = "jdbc:odbc:bookdb";private static Connection con = null;// 构造方法。如果数据库未打开，则通过创建连接打开数据库private DbOp() {try {// 如果当前未创建连接，则加载JDBC驱动程序，然后创建连接if (con == null) {Class.forName(driver);con = DriverManager.getConnection(url);}} catch (Exception e) {JOptionPane.showMessageDialog(null, "数据库未能打开！");}}// 执行数据库查询工作。如果出现异常，返回nullpublic static ResultSet executeQuery(String sql) {try {// 如果未创建数据库连接，则创建连接if (con == null)new DbOp();// 返回查询结果return con.createStatement().executeQuery(sql);} catch (SQLException e) {JOptionPane.showMessageDialog(null, "数据库不存在，或存在错误！");return null;}}// 执行数据库更新操作。如果有问题，则返回-1public static int executeUpdate(String sql) {try {// 如果未创建数据库连接，则创建连接if (con == null)new DbOp();// 返回操作结果return con.createStatement().executeUpdate(sql);} catch (SQLException e) {JOptionPane.showMessageDialog(null, "数据有误，记录无法正常保存或更新！");return -1;}}// 关闭数据库public static void Close() {try {// 如果数据库已打开，则关闭之if (con != null)con.close();} catch (SQLException e) {JOptionPane.showMessageDialog(null, "数据库未打开！");}}
}

二、BookSelect.java与ReaderSelect.java

 　这两个类分别用于按图书编号和读者编号查询记录，查询结果将分别保存在Book和Reader对象中。

// BookSelect.java
package PublicModule;import java.sql.*;import javax.swing.JOptionPane;public class BookSelect {// 按图书编号查询，查询结果保存在Book类的对象中public static Book SelectBookById(String id) {String sql = "select * from book where id='" + id + "'";ResultSet rs = DbOp.executeQuery(sql);Book book = null;try {if (rs.next()) {book = new Book();book.setId(rs.getString("id"));book.setBooktype(rs.getString("booktype"));book.setBookname(rs.getString("bookname"));book.setAuthor(rs.getString("author"));book.setTranslator(rs.getString("translator"));book.setPublisher(rs.getString("publisher"));book.setPublish_time(rs.getDate("publish_time"));book.setPrice(rs.getFloat("price"));book.setStock(rs.getInt("stock"));}} catch (SQLException e) {JOptionPane.showMessageDialog(null, "无法正常读取数据库！");}return book;}
}

// ReaderSelect.java
package PublicModule;import java.sql.*;
import javax.swing.JOptionPane;public class ReaderSelect {// 按读者编号查询，结果保存在Reader类的对象中public static Reader selectReaderById(String id) {String sql = "select * from reader where id='" + id + "'";ResultSet rs = DbOp.executeQuery(sql);Reader reader = null;try {if (rs.next()) {reader = new Reader();reader.setId(rs.getString("id"));reader.setReadername(rs.getString("readername"));reader.setReadertype(rs.getString("readertype"));reader.setSex(rs.getString("sex"));reader.setMax_num(rs.getInt("max_num"));reader.setDays_num(rs.getInt("days_num"));}} catch (SQLException e) {JOptionPane.showMessageDialog(null, "无法正常读取数据库！");}return reader;}
}

三、IfBorrowBack.java

 　该类中的findbook()方法用于查询指定读者是否借阅过指定图书。如果已经借阅且未归还，返回true，否则，返回false。

// IfBorrowBack.java
package PublicModule;import java.sql.ResultSet;
import java.sql.SQLException;import javax.swing.JOptionPane;public class IfBorrowBack {// 查指定读者是否借过指定图书且未归还public static boolean findbook(String bookid, String readerid) {String sql;sql = "select * from borrow where book_id='";sql = sql + bookid + "' and reader_id='" + readerid + "' and ";sql = sql + "if_back='否'";ResultSet rs = DbOp.executeQuery(sql);try {// 如果指定读者借阅了指定图书，且未归还，返回true，否则返回falseif (rs.next())return true;elsereturn false;} catch (SQLException e) {JOptionPane.showMessageDialog(null, "数据库查询失败！");}return true;}
}

四、公共模块中的其他类

 　（1）GlobalVar.java
 　（2）Book.java
 　（3）Reader.java

// GlobalVar.java
package PublicModule;
public class GlobalVar {// 该变量用来保存登录用户名public static String login_user;
}

// Book.java
package PublicModule;import java.sql.Date;public class Book {private String id;private String bookname;private String booktype;private String author;private String translator;private String publisher;private Date publish_time;private int stock;private float price;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getBookname() {return bookname;}public void setBookname(String name) {this.bookname = name;}public String getBooktype() {return booktype;}public void setBooktype(String type) {this.booktype = type;}public String getAuthor() {return author;}public void setAuthor(String author) {this.author = author;}public String getTranslator() {return translator;}public void setTranslator(String translator) {this.translator = translator;}public String getPublisher() {return publisher;}public void setPublisher(String publisher) {this.publisher = publisher;}public Date getPublish_time() {return publish_time;}public void setPublish_time(Date publish_time) {this.publish_time = publish_time;}public int getStock() {return stock;}public void setStock(int stock) {this.stock = stock;}public float getPrice() {return price;}public void setPrice(float price) {this.price = price;}}

// Reader.java
package PublicModule;public class Reader {private String id;private String readername;private String readertype;private String sex;private int max_num;private int days_num;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getReadername() {return readername;}public void setReadername(String name) {this.readername = name;}public String getReadertype() {return readertype;}public void setReadertype(String type) {this.readertype = type;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public int getMax_num() {return max_num;}public void setMax_num(int max_num) {this.max_num = max_num;}public int getDays_num() {return days_num;}public void setDays_num(int days_num) {this.days_num = days_num;}
}

12.3 主模块设计

一、Login.java

 　登录模块用于实现用户登录功能，也是进入系统的入口。进行系统登录时，需要输入用户名和密码，系统会查询数据库中的user表，验证用户名和密码是否正确。

// Login.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.sql.*;import javax.swing.JOptionPane;import PublicModule.*;public class Login extends Frame {private static final long serialVersionUID = -1758475247807861408L;TextField text_user;TextField text_pass;public Login() {this.setTitle("登录");this.setLayout(null);this.setSize(260, 170);/* 添加标签与文本框 */Label lbUser = new Label("用户名：");Label lbPass = new Label("密    码：");Button btn_ok = new Button("确定");Button btn_cancel = new Button("取消");text_pass = new TextField();text_user = new TextField();lbUser.setBounds(40, 53, 60, 20);lbPass.setBounds(40, 83, 60, 20);text_user.setBounds(100, 50, 120, 20);text_pass.setBounds(100, 80, 120, 20);btn_ok.setBounds(45, 120, 80, 25); // 确定按钮btn_ok.addActionListener((new ActionListener() {public void actionPerformed(ActionEvent e) {btn_okActionPerformed(e);}}));btn_cancel.setBounds(135, 120, 80, 25); // 取消按钮btn_cancel.addActionListener((new ActionListener() {public void actionPerformed(ActionEvent e) {DbOp.Close(); // 关闭数据库System.exit(0);}}));/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {DbOp.Close(); // 关闭数据库System.exit(0);}});add(lbUser);add(lbPass);add(text_user);add(text_pass);add(btn_ok);add(btn_cancel);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置this.setVisible(true); // 使窗体可见}public void btn_okActionPerformed(ActionEvent e) {String user = text_user.getText();String pass = text_pass.getText();String is_admin;// 如果用户名或密码任一为空，则终止后续操作if (user.equals("")||pass.equals("")) {JOptionPane.showMessageDialog(null, "用户名或密码不能为空！");return;}try {// 核对用户名和密码String sql = "select * from user where username=" + "'" + user+ "'and password=" + "'" + pass + "'";ResultSet rs = DbOp.executeQuery(sql);// 如果此用户存在，则记录其状态（否：不是管理员，是：是管理员）if (rs.next()) {is_admin = rs.getString("is_admin");} else {JOptionPane.showMessageDialog(null, "用户名或密码不正确！");return;}GlobalVar.login_user = user; // 记录登录的用户名ShowMain show = new ShowMain(); // 调用主程序// 只有管理员才能使用"基础管理"和"借阅管理"菜单show.setRights(is_admin);// 释放窗体及其全部组件的屏幕资源，即使释放登录窗体dispose(); // 释放当前窗体} catch (SQLException e1) {JOptionPane.showMessageDialog(null, "用户数据库有误！");}}public static void main(String[] args) {new Login();}
}

二、ShowMain.java

 　 成功登录系统后即进入系统的主界面。需要注意的是，系统会根据登录的用户类型（普通用户和管理员），决定“系统维护”和“借阅管理”菜单是否可用。

// ShowMain.java
package MainPro;import java.awt.*;
import java.awt.event.*;import PublicModule.DbOp;public class ShowMain extends Frame {private static final long serialVersionUID = 5003296786441785470L;MenuBar menuBar1;Menu menu1, menu2, menu3, menu4, menu5, menu6, menu7;MenuItem mi_book_add, mi_book_update, mi_book_delete, mi_reader_add,mi_reader_update, mi_reader_delete, mi_borrow, mi_back,mi_query_book, mi_query_reader, mi_update_pass, mi_exit;public void setRights(String rights) {// 如果不是管理员，则禁止用户维护图书信息和读者信息// 以及禁止进行借阅管理，即只能查询if (rights.equals("否")) {menu1.setEnabled(false);menu5.setEnabled(false);}}public ShowMain() {setTitle("图书管理系统");setLayout(new BorderLayout());setSize(640, 480);menuBar1 = new MenuBar();menu5 = new Menu("基础维护");// 基础维护菜单menu6 = new Menu("图书维护");// 图书维护菜单mi_book_add = new MenuItem("添加");// 添加图书菜单mi_book_update = new MenuItem("修改");// 修改图书菜单mi_book_delete = new MenuItem("删除");// 删除图书菜单menu7 = new Menu("读者维护");// 读者维护菜单mi_reader_add = new MenuItem("添加读者");// 添加读者菜单mi_reader_update = new MenuItem("修改读者");mi_reader_delete = new MenuItem("删除读者");menu1 = new Menu("借阅管理");mi_borrow = new MenuItem("借书管理");mi_back = new MenuItem("还书管理");menu2 = new Menu("查询管理");mi_query_book = new MenuItem("图书查询");mi_query_reader = new MenuItem("读者查询");menu3 = new Menu("系统管理");mi_update_pass = new MenuItem("修改密码");mi_exit = new MenuItem("退出系统");// 添加图书菜单mi_book_add.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new BookAdd();}});mi_book_update.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new BookUpdate();}});mi_book_delete.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new BookDelete();}});mi_reader_add.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new ReaderAdd();}});mi_reader_update.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new ReaderUpdate();}});mi_reader_delete.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new ReaderDelete();}});mi_borrow.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new Borrow();}});mi_back.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new Back();}});mi_query_book.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new BookQuery();}});mi_query_reader.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new ReaderQuery();}});mi_update_pass.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {new UpdatePassword();}});mi_exit.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {DbOp.Close(); // 关闭数据库System.exit(0);}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {DbOp.Close(); // 关闭数据库System.exit(0);}});menu5.add(menu6);menu6.add(mi_book_add);menu6.add(mi_book_update);menu6.add(mi_book_delete);menu5.add(menu7);menu7.add(mi_reader_add);menu7.add(mi_reader_update);menu7.add(mi_reader_delete);menu5.add(menu1);menu1.add(mi_borrow);menu1.add(mi_back);menu5.add(menu2);menu2.add(mi_query_book);menu2.add(mi_query_reader);menu5.add(menu3);menu3.add(mi_update_pass);menu3.add(mi_exit);menuBar1.add(menu5);menuBar1.add(menu1);menuBar1.add(menu2);menuBar1.add(menu3);setMenuBar(menuBar1);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new ShowMain();}
}

三、 BookAdd.java

 　该模块用于输入图书信息。其设计要点主要有：① 为确保图书编号的唯一性，图书编号不能重复；② 当出版时间、定价、库存数量无效时，可通过捕捉异常来处理；③ 正常输入并保存记录后，要给出提示信息；④ 输入并保存一个记录后，应清空文本框，让用户能够继续输入下一个记录。

// BookAdd.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import javax.swing.JOptionPane;import PublicModule.*;public class BookAdd extends Frame {private static final long serialVersionUID = 377287301994613384L;Label lbbookid = new Label("图书编号");Label lbbookname = new Label("图书名称");Label lbbooktype = new Label("图书类别");Label lbauthor = new Label("作者");Label lbtranslator = new Label("译者");Label lbpublisher = new Label("出版社");Label lbpublish_time = new Label("出版时间");Label lbprice = new Label("定价");Label lbstock = new Label("库存数量");Button saveBtn = new Button("保存");Button closeBtn = new Button("关闭");TextField tf_bookid = new TextField();TextField tf_bookname = new TextField();TextField tf_author = new TextField();TextField tf_translator = new TextField();TextField tf_publisher = new TextField();TextField tf_publish_time = new TextField();TextField tf_price = new TextField();TextField tf_stock = new TextField();Choice tf_booktype = new Choice();BookAdd() {setLayout(null);setTitle("添加图书");setSize(500, 250);lbbookid.setBounds(50, 50, 50, 20); // 图书编号tf_bookid.setBounds(110, 50, 100, 20);lbbookname.setBounds(240, 50, 50, 20); // 图书名称tf_bookname.setBounds(300, 50, 100, 20);lbbooktype.setBounds(50, 80, 50, 20); // 图书类别tf_booktype.setBounds(110, 80, 100, 20);tf_booktype.add("科技");tf_booktype.add("文学");tf_booktype.add("社科");tf_booktype.add("其他");lbauthor.setBounds(240, 80, 50, 20); // 作者tf_author.setBounds(300, 80, 100, 20);lbtranslator.setBounds(50, 110, 50, 20); // 设置译者tf_translator.setBounds(110, 110, 100, 20);lbpublisher.setBounds(240, 110, 50, 20); // 出版社tf_publisher.setBounds(300, 110, 100, 20);lbpublish_time.setBounds(50, 140, 50, 20); // 出版时间tf_publish_time.setBounds(110, 140, 100, 20);lbprice.setBounds(240, 140, 50, 20); // 定价tf_price.setBounds(300, 140, 100, 20);lbstock.setBounds(50, 170, 50, 20); // 库存数量tf_stock.setBounds(110, 170, 100, 20);saveBtn.setBounds(150, 210, 80, 25); // 保存按钮saveBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_saveActionPerformed(e);}});closeBtn.setBounds(280, 210, 80, 25);// 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) { // 关闭当前窗口dispose(); // 释放当前窗体}});add(lbbookid);add(lbbookname);add(lbbooktype);add(lbauthor);add(lbtranslator);add(lbpublisher);add(lbpublish_time);add(lbprice);add(lbstock);add(saveBtn);add(closeBtn);add(tf_bookid);add(tf_bookname);add(tf_author);add(tf_translator);add(tf_publisher);add(tf_publish_time);add(tf_price);add(tf_stock);add(tf_booktype);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}// 保存记录private void btn_saveActionPerformed(ActionEvent e) {String id = tf_bookid.getText();String bookname = tf_bookname.getText();String booktype = tf_booktype.getSelectedItem().toString();String author = tf_author.getText();String translator = tf_translator.getText();String publisher = tf_publisher.getText();String publish_time = tf_publish_time.getText();// 如果图书编号为空，则终止保存记录操作if (id.equals("")) {JOptionPane.showMessageDialog(null, "图书编号不能为空！");return;}// 如果图书编号重复，则记录无效，需修改图书编号if (IfBookIdExit(id)) {JOptionPane.showMessageDialog(null, "图书编号重复！");return;}try {// -------------------------------------------------// 以下程序用于检查日期是否有效。如果日期无效，则会// 产生ParseException异常// 创建一个简单日期格式对象，注意：MM一定要用大写// 这是用户输入日期的格式：年-月，如2010-7、2009-10等SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");// 将字符串转换为日期。如果日期无效，将抛出ParseException异常// 因此，本语句主要用来判断日期格式是否有效sdf.parse(tf_publish_time.getText());// -------------------------------------------------float price = Float.parseFloat(tf_price.getText());int stock = Integer.parseInt(tf_stock.getText());// 将记录保存到book表中String sql = "insert into book(id,bookname,booktype,"+ "author,translator,"+ "publisher,publish_time,price,stock) values('" + id+ "','" + bookname + "','" + booktype + "','" + author+ "','" + translator + "','" + publisher + "','"+ publish_time + "','" + price + "','" + stock + "')";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "图书添加成功！");// 清空全部文本框clearAllTextfield();}} catch (ParseException e2) {JOptionPane.showMessageDialog(null, "出版时间格式错误（年—月）！");} catch (NumberFormatException e1) {JOptionPane.showMessageDialog(null, "库存数量和价格错误，应为数字！");}}// 判断Book表中是否存在指定编号的图书，如果存在，返回true，否则，返回falseprivate boolean IfBookIdExit(String id) {String sql = "select * from book where id='" + id + "'";ResultSet rs = DbOp.executeQuery(sql);try {if (rs.next())return true;elsereturn false;} catch (SQLException e) {JOptionPane.showMessageDialog(null, "无法正常读取数据库！");}return false;}// 清空全部文本框private void clearAllTextfield() {tf_bookid.setText("");tf_bookname.setText("");tf_author.setText("");tf_translator.setText("");tf_publisher.setText("");tf_publish_time.setText("");tf_price.setText("");tf_stock.setText("");}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new BookAdd();}
}

四、BookUpdate.java

 　该模块用来修改图书信息。使用该功能模块时，用户应首先在“图书编号”编辑框中输入要修改图书的图书编号，然后单击“查询”按钮，将所选图书的其他数据显示出来，接下来就可以对这些数据进行修改了。

// BookUpdate.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;import javax.swing.JOptionPane;import PublicModule.*;public class BookUpdate extends Frame {private static final long serialVersionUID = -7074630570516408587L;Label lbbookid_1 = new Label("图书编号");Label lbbookid = new Label("图书编号");Label lbbookname = new Label("图书名称");Label lbbooktype = new Label("图书类别");Label lbauthor = new Label("作者");Label lbtranslator = new Label("译者");Label lbpublisher = new Label("出版社");Label lbpublish_time = new Label("出版时间");Label lbprice = new Label("定价");Label lbstock = new Label("库存数量");Button saveBtn = new Button("保存");Button closeBtn = new Button("关闭");Button queryBtn = new Button("查询");TextField tf_bookid_1 = new TextField();TextField tf_bookid = new TextField();TextField tf_bookname = new TextField();TextField tf_author = new TextField();TextField tf_translator = new TextField();TextField tf_publisher = new TextField();TextField tf_publish_time = new TextField();TextField tf_price = new TextField();TextField tf_stock = new TextField();Choice tf_booktype = new Choice();public BookUpdate() {setLayout(null);setTitle("修改图书");setSize(500, 280);lbbookid_1.setBounds(100, 40, 50, 20); // 图书编号tf_bookid_1.setBounds(160, 40, 100, 20);queryBtn.setBounds(280, 40, 80, 20); // 查询按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_queryActionPerformed(e);}});lbbookid.setBounds(50, 80, 50, 20); // 图书编号tf_bookid.setBounds(110, 80, 100, 20);tf_bookid.setEditable(false); // 禁止修改图书编号lbbookname.setBounds(240, 80, 50, 20); // 图书名称tf_bookname.setBounds(300, 80, 100, 20);lbbooktype.setBounds(50, 110, 50, 20); // 图书类别tf_booktype.setBounds(110, 110, 100, 20);tf_booktype.add("科技");tf_booktype.add("文学");tf_booktype.add("社科");tf_booktype.add("其他");lbauthor.setBounds(240, 110, 50, 20); // 作者tf_author.setBounds(300, 110, 100, 20);lbtranslator.setBounds(50, 140, 50, 20); // 译者tf_translator.setBounds(110, 140, 100, 20);lbpublisher.setBounds(240, 140, 50, 20); // 出版社tf_publisher.setBounds(300, 140, 100, 20);lbpublish_time.setBounds(50, 170, 50, 20); // 出版时间tf_publish_time.setBounds(110, 170, 100, 20);lbprice.setBounds(240, 170, 50, 20); // 价格tf_price.setBounds(300, 170, 100, 20);lbstock.setBounds(50, 200, 50, 20); // 库存数量tf_stock.setBounds(110, 200, 100, 20);saveBtn.setBounds(150, 240, 80, 25); // 保存按钮saveBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_saveActionPerformed(e);}});closeBtn.setBounds(280, 240, 80, 25); // 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbbookid);add(lbbookid_1);add(lbbookname);add(lbbooktype);add(lbauthor);add(lbtranslator);add(lbpublisher);add(lbpublish_time);add(lbprice);add(lbstock);add(saveBtn);add(closeBtn);add(queryBtn);add(tf_bookid);add(tf_bookname);add(tf_author);add(tf_translator);add(tf_publisher);add(tf_publish_time);add(tf_price);add(tf_stock);add(tf_bookid_1);add(tf_booktype);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}// 按图书编号查询图书记录public void btn_queryActionPerformed(ActionEvent e)  {String id = tf_bookid_1.getText();// 如果图书编号为空，则查询操作终止if (id.equals("")) {JOptionPane.showMessageDialog(null, "图书编号不能为空！");return;}// 按编号查询图书，结果存入book对象中Book book = BookSelect.SelectBookById(id);// 如果查询到结果，将其显示在各文本框中if (book != null) {tf_bookid.setText(book.getId());tf_bookname.setText(book.getBookname());// 将Choice的选定项设置为其名称等于指定字符串的项tf_booktype.select(book.getBooktype());tf_author.setText(book.getAuthor());tf_translator.setText(book.getTranslator());tf_publisher.setText(book.getPublisher());tf_publish_time.setText(book.getPublish_time().toString());tf_price.setText(String.valueOf(book.getPrice()));tf_stock.setText(String.valueOf(book.getStock()));} elseJOptionPane.showMessageDialog(null, "图书编号有误，查无此书！");}// 保存修改的记录private void btn_saveActionPerformed(ActionEvent e) {String id = tf_bookid.getText();String bookname = tf_bookname.getText();String booktype = tf_booktype.getSelectedItem().toString();String author = tf_author.getText();String translator = tf_translator.getText();String publisher = tf_publisher.getText();String publish_time = tf_publish_time.getText();// 如果图书编号为空，则终止保存记录操作if (id.equals("")) {JOptionPane.showMessageDialog(null, "图书编号不能为空！");return;}try {// -------------------------------------------------// 以下程序用于检查日期是否有效。如果日期无效，则会// 产生ParseException异常// 创建一个简单日期格式对象，注意：MM一定要用大写// 这是用户输入日期的格式：年-月，如2010-7、2009-10等SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");// 将字符串转换为日期sdf.parse(tf_publish_time.getText());// -------------------------------------------------float price = Float.parseFloat(tf_price.getText());int stock = Integer.parseInt(tf_stock.getText());String sql = "update book set bookname='" + bookname+ "',booktype='" + booktype + "',author='" + author+ "',translator='" + translator + "',publisher='"+ publisher + "',publish_time='" + publish_time+ "',price='" + price + "',stock='" + stock+ "' where id='" + id + "'";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "图书信息修改成功！");// 清空全部文本框clearAllTextfield();} elseJOptionPane.showMessageDialog(null, "数据有误，图书信息修改失败！");} catch (ParseException e2) {JOptionPane.showMessageDialog(null, "出版时间格式错误（年—月）！");} catch (NumberFormatException e1) {JOptionPane.showMessageDialog(null, "价格或库存数量错误，应为数字！");}}// 清空全部文本框private void clearAllTextfield() {tf_bookid_1.setText("");tf_bookid.setText("");tf_bookname.setText("");tf_author.setText("");tf_translator.setText("");tf_publisher.setText("");tf_publish_time.setText("");tf_price.setText("");tf_stock.setText("");}public static void main(String[] args) {new BookUpdate();}
}

五、BookDelete.java

 　该模块用于根据图书编号删除所选图书。执行删除操作时，用户应首先在“图书编号”编辑框中输入要删除的图书编号，然后单击“查询”按钮，调出该图书的相关信息，供用户进行确认。如果确认无误，即可单击“删除”按钮删除所选图书。

// BookDelete.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import javax.swing.JOptionPane;import PublicModule.*;public class BookDelete extends Frame {private static final long serialVersionUID = 7451605980497182697L;Label lbbookid_1 = new Label("图书编号");Label lbbookid = new Label("图书编号");Label lbbookname = new Label("图书名称");Label lbbooktype = new Label("图书类别");Label lbauthor = new Label("作者");Label lbtranslator = new Label("译者");Label lbpublisher = new Label("出版社");Label lbpublish_time = new Label("出版时间");Label lbprice = new Label("定价");Label lbstock = new Label("库存数量");Button saveBtn = new Button("删除");Button closeBtn = new Button("关闭");Button queryBtn = new Button("查询");TextField tf_bookid = new TextField();TextField tf_bookname = new TextField();TextField tf_author = new TextField();TextField tf_translator = new TextField();TextField tf_publisher = new TextField();TextField tf_publish_time = new TextField();TextField tf_price = new TextField();TextField tf_stock = new TextField();TextField tf_bookid1 = new TextField();Choice tf_booktype = new Choice();public BookDelete() {setLayout(null);setTitle("删除图书");setSize(500, 280);lbbookid_1.setBounds(100, 40, 50, 20);// 图书编号tf_bookid1.setBounds(160, 40, 100, 20);queryBtn.setBounds(280, 40, 80, 20); // 查询按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_queryActionPerformed(e);}});lbbookid.setBounds(50, 80, 50, 20); // 图书编号tf_bookid.setBounds(110, 80, 100, 20);lbbookname.setBounds(240, 80, 50, 20); // 图书名称tf_bookname.setBounds(300, 80, 100, 20);lbbooktype.setBounds(50, 110, 50, 20); // 图书类别tf_booktype.setBounds(110, 110, 100, 20);tf_booktype.add("科技");tf_booktype.add("文学");tf_booktype.add("社科");tf_booktype.add("其他");lbauthor.setBounds(240, 110, 50, 20); // 作者tf_author.setBounds(300, 110, 100, 20);lbtranslator.setBounds(50, 140, 50, 20); // 译者tf_translator.setBounds(110, 140, 100, 20);lbpublisher.setBounds(240, 140, 50, 20); // 出版社tf_publisher.setBounds(300, 140, 100, 20);lbpublish_time.setBounds(50, 170, 50, 20); // 出版时间tf_publish_time.setBounds(110, 170, 100, 20);lbprice.setBounds(240, 170, 50, 20); // 价格tf_price.setBounds(300, 170, 100, 20);lbstock.setBounds(50, 200, 50, 20);// 库存数量tf_stock.setBounds(110, 200, 100, 20);saveBtn.setBounds(150, 240, 80, 25); // 删除按钮saveBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_delActionPerformed(e);}});closeBtn.setBounds(280, 240, 80, 25); // 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbbookid); // 将各组件增加到窗体中add(lbbookid_1);add(lbbookname);add(lbbooktype);add(lbauthor);add(lbtranslator);add(lbpublisher);add(lbpublish_time);add(lbprice);add(lbstock);add(saveBtn);add(closeBtn);add(queryBtn);add(tf_bookid);add(tf_bookname);add(tf_author);add(tf_translator);add(tf_publisher);add(tf_publish_time);add(tf_price);add(tf_stock);add(tf_bookid1);add(tf_booktype);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void btn_delActionPerformed(ActionEvent e) {String id = tf_bookid.getText();// 如果图书编号为空，则删除操作终止if (id.equals("")) {JOptionPane.showMessageDialog(null, "图书编号不能为空！");return;}String sql = "delete from book where id='" + id + "'";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "图书信息删除成功!");// 清空全部文本框clearAllTextfield();} elseJOptionPane.showMessageDialog(null, "图书信息删除失败！");}private void btn_queryActionPerformed(ActionEvent e) {String id = tf_bookid1.getText();// 如果图书编号为空，则查询操作终止if (id.equals("")) {JOptionPane.showMessageDialog(null, "图书编号不能为空！");return;}// 按编号查询图书，结果存入book对象中Book book = BookSelect.SelectBookById(id);// 如果查询到结果，将其显示在各文本框中if (book != null) {tf_bookid.setText(book.getId());tf_bookid.setEditable(false);tf_bookname.setText(book.getBookname());// 将Choice的选定项设置为其名称等于指定字符串的项tf_booktype.select(book.getBooktype());tf_author.setText(book.getAuthor());tf_translator.setText(book.getTranslator());tf_publisher.setText(book.getPublisher());tf_publish_time.setText(book.getPublish_time().toString());tf_price.setText(String.valueOf((book.getPrice())));tf_stock.setText(String.valueOf(book.getStock()));} elseJOptionPane.showMessageDialog(null, "图书编号有误，查无此书！");}// 清空全部文本框private void clearAllTextfield() {tf_bookid1.setText("");tf_bookid.setText("");tf_bookname.setText("");tf_author.setText("");tf_translator.setText("");tf_publisher.setText("");tf_publish_time.setText("");tf_price.setText("");tf_stock.setText("");}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new BookDelete();}
}

六、BookQuery.java

 　该模块用于根据图书名称、作者、出版社、出版时间等信息进行图书查询。这四个条件之间的关系为逻辑与关系。如果在某个编辑框中不输入内容，则忽略该条件。如果在四个编辑框中均不输入任何内容，表示显示全部图书信息。

// BookQuery.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.text.*;
import java.util.*;
import java.util.Date;import javax.swing.*;import PublicModule.*;public class BookQuery extends JFrame {private static final long serialVersionUID = -3045513015088987091L;JTable table;JScrollPane scrollPane;Label lbbookname = new Label("图书名称");Label lbauthor = new Label("作        者");Label lbpublisher = new Label("出  版  社");Label lbpublish_time = new Label("出版时间");Label lbnotes = new Label("（年—月）");TextField tf_bookname = new TextField("");TextField tf_author = new TextField("");TextField tf_publisher = new TextField("");TextField tf_publish_time = new TextField("");Button queryBtn = new Button("查询");Button closeBtn = new Button("关闭");String[] heads = { "图书编号", "图书名称", "图书类别", "作者", "译者", "出版社", "出版日期", "定价","库存数量" };// 构造方法public BookQuery() {setTitle("图书查询"); // 设置窗体标题setSize(800, 500); // 设置窗体尺寸setLayout(null); // 取消窗体布局lbbookname.setBounds(170, 20, 50, 20); // 书名tf_bookname.setBounds(230, 20, 160, 20);lbauthor.setBounds(410, 20, 50, 20); // 作者tf_author.setBounds(470, 20, 160, 20);lbpublisher.setBounds(170, 50, 50, 20); // 出版社tf_publisher.setBounds(230, 50, 160, 20);lbpublish_time.setBounds(410, 40, 50, 20); // 出版时间lbnotes.setBounds(405, 60, 60, 20);tf_publish_time.setBounds(470, 50, 160, 20);queryBtn.setBounds(300, 90, 80, 25); // 查询按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_queryActionPerformed(e);}});closeBtn.setBounds(420, 90, 80, 25);// 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbbookname); // 将各组件添加到窗体中add(tf_bookname);add(lbauthor);add(tf_author);add(lbpublisher);add(tf_publisher);add(lbpublish_time);add(lbnotes);add(tf_publish_time);add(queryBtn);add(closeBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void btn_queryActionPerformed(ActionEvent e) {try {String bookname, author, publisher, publishtime;String sql, sql1, sql2, sql3, sql4, sql5;String pubyear, pubmonth;bookname = tf_bookname.getText();author = tf_author.getText();publisher = tf_publisher.getText();publishtime = tf_publish_time.getText();// 创建一条基本的SQL语句，表示选出表中全部记录sql = "select * from book ";// 如果书名不空，生成sql1字句if (bookname.equals(""))sql1 = "";elsesql1 = " bookname like '" + bookname + "%' ";// 如果作者不空，生成sql2字句if (author.equals(""))sql2 = "";else {sql2 = " author like '" + author + "%' ";if (!bookname.equals("")) // 如果书名不为空sql2 = " and " + sql2;}// 如果出版社不空，生成sql3字句if (publisher.equals(""))sql3 = "";else {sql3 = "publisher like '" + publisher + "%' ";// 如果书名和作者有一项不为空if (!(bookname.equals("") && author.equals("")))sql3 = " and " + sql3;}// 如果出版日期不空，生成sql4字句if (publishtime.equals("")) {sql4 = "";} else {// 创建一个简单日期格式对象，注意：MM一定要用大写// 这是用户输入日期的格式：年-月，如2010-7、2009-10等SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");// 创建一个Calendar对象Calendar cal = new GregorianCalendar();// 将字符串转换为日期Date pubtime = sdf.parse(tf_publish_time.getText());// 使用给定日期设置cal的时间cal.setTime(pubtime);// 获取年pubyear = String.valueOf(cal.get(Calendar.YEAR));// 获取月pubmonth = String.valueOf(cal.get(Calendar.MONTH) + 1);sql4 = " year(publish_time)=" + pubyear + " and ";sql4 = sql4 + "month(publish_time)=" + pubmonth;// 如果书名、作者或出版社有一项不为空if (!(bookname.equals("") && author.equals("") && publisher.equals("")))sql4 = " and " + sql4;}sql5 = sql1 + sql2 + sql3 + sql4;// 如果已设置任意一项条件，则修改SQL语句if (!sql5.equals("")) {sql = sql + " where " + sql5;}// 执行查询ResultSet rs = DbOp.executeQuery(sql);// 创建一个对象二维数组Object[][] bookq = new Object[30][heads.length];int i = 0; // 定义一个变量while (rs.next()) { // 将查询结果赋予Book数组bookq[i][0] = rs.getString("id");bookq[i][1] = rs.getString("bookname");bookq[i][2] = rs.getString("booktype");bookq[i][3] = rs.getString("author");bookq[i][4] = rs.getString("translator");bookq[i][5] = rs.getString("publisher");bookq[i][6] = rs.getDate("publish_time");bookq[i][7] = rs.getFloat("price");bookq[i][8] = rs.getInt("stock");i++;}table = new JTable(bookq, heads); // 创建一个表格// 创建一个显示表格的JScrollPanescrollPane = new JScrollPane(table);// 设置JScrollPane的位置和尺寸scrollPane.setBounds(20, 140, 760, 300);// 将JScrollPane添加到窗体中add(scrollPane);} catch (ParseException e2) {JOptionPane.showMessageDialog(null, "出版时间格式错误（年—月）！");} catch (SQLException e1) {JOptionPane.showMessageDialog(null, "数据库不存在，或存在错误！");}}// 为了便于调试程序，特别创建main方法public static void main(String[] args) {new BookQuery();}
}

七、读者信息的录入、修改、删除和查询模块

 　读者信息的录入、修改、删除和查询模块与图书相关模块在功能和设计上完全类似。

// ReaderAdd.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.sql.ResultSet;
import java.sql.SQLException;import javax.swing.JOptionPane;import PublicModule.*;public class ReaderAdd extends Frame {private static final long serialVersionUID = -2399939451497711745L;Label lbreaderid = new Label("读者编号");Label lbreadername = new Label("读者姓名");Label lbreadertype = new Label("读者类别");Label lbsex = new Label("性别");Label lbmax_num = new Label("可借数量");Label lbdays_num = new Label("可借天数");TextField tf_readerid = new TextField();TextField tf_readername = new TextField();TextField tf_max_num = new TextField();TextField tf_days_num = new TextField();Choice tf_readertype = new Choice();Choice tf_sex = new Choice();Button saveBtn = new Button("保存");Button closeBtn = new Button("关闭");public ReaderAdd() {setLayout(null);setTitle("添加读者信息");setSize(500, 200);lbreaderid.setBounds(50, 50, 50, 20); // 读者编号tf_readerid.setBounds(110, 50, 100, 20);lbreadername.setBounds(240, 50, 50, 20); // 读者姓名tf_readername.setBounds(300, 50, 100, 20);lbreadertype.setBounds(50, 80, 50, 20); // 读者类别tf_readertype.setBounds(110, 80, 100, 20);tf_readertype.add("教师");tf_readertype.add("学生");tf_readertype.add("职工");lbsex.setBounds(240, 80, 50, 20); // 性别tf_sex.setBounds(300, 80, 100, 20);tf_sex.add("男");tf_sex.add("女");lbmax_num.setBounds(50, 110, 50, 20); // 最大可借数tf_max_num.setBounds(110, 110, 100, 20);lbdays_num.setBounds(240, 110, 50, 20); // 最大可借天数tf_days_num.setBounds(300, 110, 100, 20);saveBtn.setBounds(150, 150, 80, 25); // 保存按钮saveBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_saveActionPerformed(e);}});closeBtn.setBounds(280, 150, 80, 25);// 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbreaderid);add(lbreadername);add(lbreadertype);add(lbsex);add(lbmax_num);add(lbdays_num);add(tf_readerid);add(tf_readername);add(tf_max_num);add(tf_days_num);add(tf_readertype);add(tf_sex);add(saveBtn);add(closeBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void btn_saveActionPerformed(ActionEvent e) {String id = tf_readerid.getText();String name = tf_readername.getName();String type = tf_readertype.getSelectedItem().toString();String sex = tf_sex.getSelectedItem().toString();// 如果读者编号为空，则终止保存记录操作if (id.equals("")) {JOptionPane.showMessageDialog(null, "读者编号不能为空！");return;}// 如果读者编号重复，则记录无效，需修改读者编号if (IfReaderIdExit(id)) {JOptionPane.showMessageDialog(null, "读者编号重复！");return;}try {int max_num = Integer.parseInt(tf_max_num.getText());int days_num = Integer.parseInt(tf_days_num.getText());String sql = "insert into reader(id,name,type,sex,"+ "max_num,days_num) values('" + id + "','" + name + "','"+ type + "','" + sex + "','" + max_num + "','" + days_num+ "')";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "读者添加成功！");// 清空全部文本框clearAllTextfield();}} catch (NumberFormatException e1) {JOptionPane.showMessageDialog(null, "最大可借数或"+ "最大可借天数错误，应为整数！");}}// 判断Reader表中是否存在指定编号的读者，如果存在，返回true，否则，返回falseprivate boolean IfReaderIdExit(String id) {String sql = "select * from reader where id='" + id + "'";ResultSet rs = DbOp.executeQuery(sql);try {if (rs.next())return true;elsereturn false;} catch (SQLException e) {JOptionPane.showMessageDialog(null, "无法正常读取数据库！");}return false;}// 清空全部文本框private void clearAllTextfield() {tf_readerid.setText("");tf_readername.setText("");tf_max_num.setText("");tf_days_num.setText("");}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new ReaderAdd();}
}

// ReaderUpdate.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import javax.swing.JOptionPane;import PublicModule.*;public class ReaderUpdate extends Frame {private static final long serialVersionUID = -4657058729583467505L;Label lbreaderid_1 = new Label("读者编号");Label lbreaderid = new Label("读者编号");Label lbreadername = new Label("读者姓名");Label lbreadertype = new Label("读者类别");Label lbsex = new Label("性别");Label lbmax_num = new Label("可借数量");Label lbdays_num = new Label("可借天数");TextField tf_readerid1 = new TextField();TextField tf_readerid = new TextField();TextField tf_readername = new TextField();TextField tf_max_num = new TextField();TextField tf_days_num = new TextField();Choice tf_readertype = new Choice();Choice tf_sex = new Choice();Button queryBtn = new Button("查询");Button saveBtn = new Button("保存");Button closeBtn = new Button("关闭");public ReaderUpdate() {setLayout(null);setTitle("修改读者信息");setSize(500, 240);lbreaderid_1.setBounds(100, 40, 50, 20); // 读者编号tf_readerid1.setBounds(160, 40, 100, 20);queryBtn.setBounds(290, 40, 80, 20); // 查询按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_queryActionPerformed(e);}});lbreaderid.setBounds(50, 80, 50, 20); // 读者编号tf_readerid.setBounds(110, 80, 100, 20);tf_readerid.setEditable(false); // 禁止修改读者编号lbreadername.setBounds(240, 80, 50, 20); // 读者姓名tf_readername.setBounds(300, 80, 100, 20);lbreadertype.setBounds(50, 110, 50, 20); // 读者类别tf_readertype.setBounds(110, 110, 100, 20);tf_readertype.add("教师");tf_readertype.add("学生");tf_readertype.add("职工");lbsex.setBounds(240, 110, 50, 20); // 性别tf_sex.setBounds(300, 110, 100, 20);tf_sex.add("男");tf_sex.add("女");lbmax_num.setBounds(50, 140, 50, 20); // 最大可借数tf_max_num.setBounds(110, 140, 100, 20);lbdays_num.setBounds(240, 140, 50, 20); // 最大可借天数tf_days_num.setBounds(300, 140, 100, 20);saveBtn.setBounds(150, 180, 80, 25); // 保存按钮saveBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_saveActionPerformed(e);}});closeBtn.setBounds(280, 180, 80, 25);// 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbreaderid_1);add(lbreaderid);add(lbreadername);add(lbreadertype);add(lbsex);add(lbmax_num);add(lbdays_num);add(tf_readerid1);add(tf_readerid);add(tf_readername);add(tf_max_num);add(tf_days_num);add(tf_readertype);add(tf_sex);add(saveBtn);add(closeBtn);add(queryBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void btn_queryActionPerformed(ActionEvent e) {String id = tf_readerid1.getText();// 如果读者编号为空，则终止查询操作if (id.equals("")) {JOptionPane.showMessageDialog(null, "读者编号不能为空！");return;}// 按编号查询读者，结果存入reader对象中Reader reader = ReaderSelect.selectReaderById(id);// 如果查询到结果，将其显示在各文本框中if (reader != null) {tf_readerid.setText(reader.getId());tf_readername.setText(reader.getReadername());// 将Choice的选定项设置为其名称等于指定字符串的项tf_readertype.select(reader.getReadertype());tf_sex.select(reader.getSex());tf_days_num.setText(String.valueOf(reader.getDays_num()));tf_max_num.setText(String.valueOf(reader.getMax_num()));} elseJOptionPane.showMessageDialog(null, "读者编号有误，查无此人！");}private void btn_saveActionPerformed(ActionEvent e) {String id = tf_readerid.getText();String readername = tf_readername.getText();String readertype = tf_readertype.getSelectedItem().toString();// 如果读者编号为空，则终止保存记录操作if (id.equals("")) {JOptionPane.showMessageDialog(null, "读者编号不能为空！");return;}try {int max_num = Integer.parseInt(tf_max_num.getText());int days_num = Integer.parseInt(tf_days_num.getText());String sex = tf_sex.getSelectedItem().toString();String sql = "update reader set readername='" + readername+ "',readertype='" + readertype + "',days_num='" + days_num+ "',sex='" + sex + "',max_num='" + max_num+ "' where id='" + id + "'";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "读者信息修改成功！");// 清空全部文本框clearAllTextfield();} elseJOptionPane.showMessageDialog(null, "读者信息修改失败！");} catch (NumberFormatException e1) {JOptionPane.showMessageDialog(null, "最大可借数或最大可借" + "天数错误，应为整数！");}}// 清空全部文本框private void clearAllTextfield() {tf_readerid1.setText("");tf_readerid.setText("");tf_readername.setText("");tf_max_num.setText("");tf_days_num.setText("");}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new ReaderUpdate();}
}

// ReaderDelete.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import javax.swing.JOptionPane;import PublicModule.*;public class ReaderDelete extends Frame {private static final long serialVersionUID = 8992814149454286463L;Label lbreaderid = new Label("读者编号");Label lbreaderid_1 = new Label("读者编号");Label lbreadername = new Label("读者姓名");Label lbreadertype = new Label("读者类别");Label lbsex = new Label("性别");Label lbmax_num = new Label("可借数量");Label lbdays_num = new Label("可借天数");TextField tf_readerid = new TextField();TextField tf_readername = new TextField();TextField tf_max_num = new TextField();TextField tf_days_num = new TextField();TextField tf_readerid1 = new TextField();Choice tf_readertype = new Choice();Choice tf_sex = new Choice();Button queryBtn = new Button("查询");Button delBtn = new Button("删除");Button closeBtn = new Button("关闭");public ReaderDelete() {setLayout(null);setTitle("删除读者信息");setSize(500, 240);lbreaderid_1.setBounds(100, 40, 50, 20); // 读者编号tf_readerid1.setBounds(160, 40, 100, 20);queryBtn.setBounds(290, 40, 80, 20); // 查询按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_queryActionPerformed(e);}});lbreaderid.setBounds(50, 80, 50, 20); // 读者编号tf_readerid.setBounds(110, 80, 100, 20);lbreadername.setBounds(240, 80, 50, 20); // 读者姓名tf_readername.setBounds(300, 80, 100, 20);lbreadertype.setBounds(50, 110, 50, 20); // 读者类别tf_readertype.setBounds(110, 110, 100, 20);tf_readertype.add("教师");tf_readertype.add("学生");tf_readertype.add("职工");lbsex.setBounds(240, 110, 50, 20); // 性别tf_sex.setBounds(300, 110, 100, 20);tf_sex.add("男");tf_sex.add("女");lbmax_num.setBounds(50, 140, 50, 20); // 最大可借数tf_max_num.setBounds(110, 140, 100, 20);lbdays_num.setBounds(240, 140, 50, 20); // 最大可借天数tf_days_num.setBounds(300, 140, 100, 20);delBtn.setBounds(150, 180, 80, 25); // 删除按钮delBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_delActionPerformed(e);}});closeBtn.setBounds(280, 180, 80, 25); // 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbreaderid); // 将各组件添加到窗体中add(lbreaderid_1);add(lbreadername);add(lbreadertype);add(lbsex);add(lbmax_num);add(lbdays_num);add(tf_readerid);add(tf_readername);add(tf_max_num);add(tf_days_num);add(tf_readerid1);add(tf_readertype);add(tf_sex);add(delBtn);add(closeBtn);add(queryBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void btn_delActionPerformed(ActionEvent e) {String id = tf_readerid.getText();// 如果读者编号为空，则终止删除操作if (id.equals("")) {JOptionPane.showMessageDialog(null, "读者编号不能为空！");return;}String sql = "delete from reader where id='" + id + "'";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "读者信息删除成功！");// 清空全部文本框clearAllTextfield();} elseJOptionPane.showMessageDialog(null, "读者编号有误，查无此人！");}private void btn_queryActionPerformed(ActionEvent e) {String id = tf_readerid1.getText();if (id.equals("")) {JOptionPane.showMessageDialog(null, "读者编号不能为空！");return;}// 按编号查询读者，结果存入reader对象中Reader reader = ReaderSelect.selectReaderById(id);// 如果查询到结果，将其显示在各文本框中if (reader != null) {tf_readerid.setText(reader.getId());tf_readerid.setEditable(false);tf_readername.setText(reader.getReadername());// 将Choice的选定项设置为其名称等于指定字符串的项tf_readertype.select(reader.getReadertype());tf_sex.select(reader.getSex());tf_max_num.setText(String.valueOf(reader.getMax_num()));tf_days_num.setText(String.valueOf(reader.getDays_num()));} elseJOptionPane.showMessageDialog(null, "读者编号有误，查无此人！");}// 清空全部文本框private void clearAllTextfield() {tf_readerid1.setText("");tf_readerid.setText("");tf_readername.setText("");tf_max_num.setText("");tf_days_num.setText("");}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new ReaderDelete();}
}

// ReaderQuery.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;
import PublicModule.*;public class ReaderQuery extends JFrame {private static final long serialVersionUID = -7717113202745852409L;JTable table;JScrollPane scrollPane;Label lbreadername = new Label("读者姓名");Label lbreadertype = new Label("读者类型");TextField tf_readername = new TextField("");TextField tf_readertype = new TextField("");Button queryBtn = new Button("查询");Button closeBtn = new Button("关闭");String[] heads = { "读者编号", "读者姓名", "读者类型", "读者性别", "最大可借数", "可借天数" };// 构造方法public ReaderQuery() {setTitle("读者查询"); // 设置窗体标题setSize(600, 500); // 设置窗体尺寸setLayout(null); // 取消窗体布局lbreadername.setBounds(70, 20, 50, 20); // 读者姓名tf_readername.setBounds(130, 20, 160, 20);lbreadertype.setBounds(310, 20, 50, 20); // 读者类别tf_readertype.setBounds(370, 20, 160, 20);queryBtn.setBounds(200, 60, 80, 25); // 查询按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_queryActionPerformed(e);}});closeBtn.setBounds(320, 60, 80, 25); // 关闭按钮closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放当前窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放当前窗体}});add(lbreadername); // 将各组件添加到窗体中add(tf_readername);add(lbreadertype);add(tf_readertype);add(queryBtn);add(closeBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void btn_queryActionPerformed(ActionEvent e) {try {String readername, readertype;String sql, sql1, sql2, sql3;readername = tf_readername.getText();readertype = tf_readertype.getText();// 创建一条基本的SQL语句，表示选出表中全部记录sql = "select * from reader ";// 如果读者姓名不空，生成sql1字句if (readername.equals(""))sql1 = "";elsesql1 = " readername like '" + readername + "%' ";// 如果作者不空，生成sql2字句if (readertype.equals(""))sql2 = "";else {sql2 = " readertype like '" + readertype + "%' ";if (!readername.equals("")) // 如果书名不为空sql2 = " and " + sql2;}sql3 = sql1 + sql2;// 如果已设置任意一项条件，则修改SQL语句if (!sql3.equals("")) {sql = sql + " where " + sql3;}// 执行查询ResultSet rs = DbOp.executeQuery(sql);// 创建一个对象二维数组Object[][] readerq = new Object[30][heads.length];int i = 0; // 定义一个变量while (rs.next()) { // 将查询结果赋予Book数组readerq[i][0] = rs.getString("id");readerq[i][1] = rs.getString("readername");readerq[i][2] = rs.getString("readertype");readerq[i][3] = rs.getString("sex");readerq[i][4] = rs.getString("max_num");readerq[i][5] = rs.getString("days_num");i++;}table = new JTable(readerq, heads); // 创建一个表格// 创建一个显示表格的JScrollPanescrollPane = new JScrollPane(table);// 设置JScrollPane的位置和尺寸scrollPane.setBounds(20, 120, 560, 300);// 将JScrollPane添加到窗体中add(scrollPane);} catch (SQLException e1) {JOptionPane.showMessageDialog(null, "数据库不存在，或存在错误！");}}// 为了便于调试程序，特别创建main方法public static void main(String[] args) {new ReaderQuery();}
}

八、Borrow.java

 　该模块用于执行借书操作。用户应首先输入图书编号和读者编号，然后做如下几个判断：① 所选图书是否存在，是否有库存；② 读者是否借过此书且未归还；③ 读者当前已借且未归还的图书是否超出了允许其最大可借数。如果上述条件都满足，“借出”按钮才有效，单击之可由程序填写借书记录 。

// Borrow.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.Date;import javax.swing.JOptionPane;import PublicModule.*;public class Borrow extends Frame {private static final long serialVersionUID = -1036076990599464079L;String SepLine = "-------------------------------------------------";Label lbbookid = new Label("图书编号");Label lbreaderid = new Label("读者编号");TextField tf_bookid = new TextField();TextField tf_readerid = new TextField();Button queryBtn = new Button("查询");Label lbbookinfo = new Label(SepLine + "图书信息" + SepLine);Label lbbookname = new Label("图书名称：");Label tf_bookname = new Label("xx");Label lbauthor = new Label("作者：");Label tf_author = new Label("xx");Label lbpublisher = new Label("出版社：");Label tf_publisher = new Label("xx");Label lbpublish_time = new Label("出版时间：");Label tf_publish_time = new Label("xx");Label lbprice = new Label("定价：");Label tf_price = new Label("xx");Label lbstock = new Label("库存数量：");Label tf_stock = new Label("xx");Label lbreaderinfo = new Label(SepLine + "读者信息" + SepLine);Label lbreadername = new Label("读者姓名：");Label tf_readername = new Label("xx");Label lbreadertype = new Label("读者类型：");Label tf_readertype = new Label("xx");Label lbmax_num = new Label("最大可借数：");Label tf_max_num = new Label("xx");Label lbdays_num = new Label("最大可借天数：");Label tf_days_num = new Label("xx");Label lbborrowinfo = new Label(SepLine + "借阅信息" + SepLine);Label lbborrowednum = new Label("该读者已借图书数量：");Label tf_borrowednum = new Label("xx");Label lbif_borrow = new Label("该读者是否可借所选图书：");Label tf_if_borrow = new Label("xx");Label lbborrow_date = new Label("借阅日期：");Label tf_borrow_date = new Label("xx");Button borrowBtn = new Button("借出");Button closeBtn = new Button("关闭");public Borrow() {setLayout(null);setTitle("借阅图书");setSize(500, 420);this.setForeground(Color.BLACK); // 设置前景色为黑色lbbookid.setBounds(30, 40, 50, 25); // 图书编号tf_bookid.setBounds(90, 40, 90, 20);lbreaderid.setBounds(200, 40, 50, 25); // 读者编号tf_readerid.setBounds(260, 40, 90, 20);queryBtn.setBounds(370, 40, 80, 25); // 查询按钮lbbookinfo.setBounds(30, 70, 440, 25); // 图书信息提示条lbbookname.setBounds(30, 100, 60, 25); // 图书名称tf_bookname.setBounds(90, 100, 200, 25);lbauthor.setBounds(310, 100, 60, 25); // 作者tf_author.setBounds(370, 100, 90, 25);lbpublisher.setBounds(30, 125, 60, 25); // 出版社tf_publisher.setBounds(90, 125, 200, 25);lbpublish_time.setBounds(310, 125, 60, 25); // 出版时间tf_publish_time.setBounds(370, 125, 90, 25);lbprice.setBounds(30, 150, 60, 25); // 定价tf_price.setBounds(90, 150, 200, 25);lbstock.setBounds(310, 150, 60, 25); // 库存数量tf_stock.setBounds(370, 150, 90, 25);lbreaderinfo.setBounds(30, 180, 440, 25); // 读者信息提示条lbreadername.setBounds(30, 205, 60, 25); // 读者姓名tf_readername.setBounds(90, 205, 90, 25);lbreadertype.setBounds(310, 205, 60, 25); // 读者类型tf_readertype.setBounds(370, 205, 90, 25);lbmax_num.setBounds(30, 230, 75, 25); // 最大可借数tf_max_num.setBounds(105, 230, 90, 25);lbdays_num.setBounds(310, 230, 85, 25); // 最大可借天数tf_days_num.setBounds(395, 230, 70, 25);lbborrowinfo.setBounds(30, 260, 440, 25); // 借阅信息提示条lbborrowednum.setBounds(30, 285, 120, 25);// 已借图书数量tf_borrowednum.setBounds(150, 285, 50, 25);lbif_borrow.setBounds(30, 310, 145, 25); // 是否可借tf_if_borrow.setBounds(175, 310, 50, 25);lbborrow_date.setBounds(30, 335, 60, 25);// 借书日期tf_borrow_date.setBounds(90, 335, 100, 25);borrowBtn.setBounds(160, 365, 80, 25);// 借出按钮borrowBtn.setEnabled(false); // 开始时禁用借出按钮closeBtn.setBounds(260, 365, 80, 25);// 关闭按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_querywActionPerformed(e);}});borrowBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_borrowActionPerformed(e);}});closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {setForeground(Color.BLACK); // 设置前景色为黑色dispose(); // 关闭窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {setForeground(Color.BLACK); // 设置前景色为黑色dispose(); // 关闭窗体}});add(lbbookid);add(lbreaderid);add(queryBtn);add(lbbookinfo);add(lbbookname);add(lbauthor);add(lbpublisher);add(lbpublish_time);add(lbprice);add(lbstock);add(lbreaderinfo);add(lbreadername);add(lbreadertype);add(lbmax_num);add(lbdays_num);add(lbborrowinfo);add(lbborrowednum);add(lbif_borrow);add(lbborrow_date);add(borrowBtn);add(closeBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见setForeground(Color.RED); // 设置前景色为红色add(tf_bookid);add(tf_readerid);add(tf_bookname);add(tf_author);add(tf_publisher);add(tf_publish_time);add(tf_price);add(tf_stock);add(tf_readername);add(tf_readertype);add(tf_max_num);add(tf_days_num);add(tf_borrowednum);add(tf_if_borrow);add(tf_borrow_date);}// 图书和读者查询private void btn_querywActionPerformed(ActionEvent e) {String bookid = tf_bookid.getText();String readerid = tf_readerid.getText();// 如果图书编号或读者编号两者均为空，或者有一个为空，则返回if (bookid.equals("") || readerid.equals("")) {JOptionPane.showMessageDialog(null, "图书编号和读者编号均不能为空！");init(); // 重新初始化各参数并禁止借出按钮return;}// 按编号查询图书，结果存入book对象中Book book = BookSelect.SelectBookById(bookid);// 如果查询到结果，将其显示在各文本框中if (book != null) {tf_bookname.setText(book.getBookname());tf_author.setText(book.getAuthor());tf_publisher.setText(book.getPublisher());tf_publish_time.setText(book.getPublish_time().toString());tf_price.setText(String.valueOf((book.getPrice())));tf_stock.setText(String.valueOf(book.getStock()));} else {JOptionPane.showMessageDialog(null, "图书编号有误，查无此书！");init(); // 重新初始化各参数并禁止借出按钮return;}if (book.getStock() == 0) {JOptionPane.showMessageDialog(null, "图书已无库存，无法借阅！");init(); // 重新初始化各参数并禁止借出按钮return;}// 按编号查询读者，结果存入reader对象中Reader reader = ReaderSelect.selectReaderById(readerid);// 如果查询到结果，将其显示在各文本框中if (reader != null) {tf_readername.setText(reader.getReadername());tf_readertype.setText(reader.getReadertype());tf_max_num.setText(String.valueOf(reader.getMax_num()));tf_days_num.setText(String.valueOf(reader.getDays_num()));} else {JOptionPane.showMessageDialog(null, "读者编号有误，查无此人！");init(); // 重新初始化各参数并禁止借出按钮return;}// 查询指定读者是否已借过指定图书且未归还if (IfBorrowBack.findbook(bookid, readerid)) {JOptionPane.showMessageDialog(null, "该读者已借阅所选图书，且未归还！");init(); // 重新初始化各参数并禁止借出按钮return;}// 统计读者所借图书数量int borrowednum = statborrowednum(readerid);tf_borrowednum.setText(String.valueOf(borrowednum));// 如果读者已借图书尚未超出其允许最大借书量，则允许其继续借阅所选图书if (borrowednum < reader.getMax_num()) {tf_if_borrow.setText("是");// 创建一个简单日期格式对象，注意：MM一定要用大写SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");// 创建日期变量，其内容为当前日期Date currentdate = new Date();// 将日期按指定格式输出String borrowdate = sdf.format(currentdate);tf_borrow_date.setText(borrowdate);borrowBtn.setEnabled(true); // 使借出按钮有效} else {JOptionPane.showMessageDialog(null, "该读者借书过多，无法继续借阅！");init(); // 重新初始化各参数并禁止借出按钮return;}}// 填写借出图书记录private void btn_borrowActionPerformed(ActionEvent e) {String sql;String bookid = tf_bookid.getText();String readerid = tf_readerid.getText();String borrowdate = tf_borrow_date.getText();// 为borrow表增加借书记录sql = "insert into borrow (book_id,reader_id,"+ "borrow_date,if_back) values('" + bookid + "','" + readerid+ "','" + borrowdate + "','否')";DbOp.executeUpdate(sql);// 将该读者所借图书数量加1int iborrowednum = Integer.parseInt(tf_borrowednum.getText()) + 1;String cborrowednum = String.valueOf(iborrowednum);tf_borrowednum.setText(cborrowednum);// 将图书库存数量减1int istock = Integer.parseInt(tf_stock.getText()) - 1;String cstock = String.valueOf(istock);// 更新画面中的图书库存数量tf_stock.setText(cstock);// 更新数据库中的图书库存数量sql = "update book set stock='" + cstock;sql = sql + "' where id='" + bookid + "'";DbOp.executeUpdate(sql);JOptionPane.showMessageDialog(null, "借书成功！");init(); // 重新初始化各参数并禁止借出按钮}// 统计某个读者当前已借图书且未归还的数量private int statborrowednum(String readerid) {int borrowednum = 0;String reader_id, if_back;// 读取数据库中记录String sql = "select * from borrow";ResultSet rs = DbOp.executeQuery(sql);// 执行查询统计操作try {while (rs.next()) {reader_id = rs.getString("reader_id");if_back = rs.getString("if_back");if (reader_id.equals(readerid) && if_back.equals("否")) {borrowednum++;}}} catch (SQLException e) {JOptionPane.showMessageDialog(null, "数据库统计失败！");}return borrowednum;}// 初始化各参数项并禁止借出按钮private void init() {tf_bookname.setText("xx");tf_author.setText("xx");tf_publisher.setText("xx");tf_publish_time.setText("xx");tf_price.setText("xx");tf_stock.setText("xx");tf_readername.setText("xx");tf_readertype.setText("xx");tf_max_num.setText("xx");tf_days_num.setText("xx");tf_borrowednum.setText("xx");tf_if_borrow.setText("xx");tf_borrow_date.setText("xx");borrowBtn.setEnabled(false); // 禁止借出按钮}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new Borrow();}
}

九、Back.java

 　该模块用于完成还书操作，此时只需判断该读者是否曾经借过此书且未归还就可以了。

// Back.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import java.text.SimpleDateFormat;
import java.util.Date;import javax.swing.JOptionPane;import PublicModule.*;public class Back extends Frame {private static final long serialVersionUID = -1036076990599464079L;String SepLine = "-------------------------------------------------";Label lbbookid = new Label("图书编号");Label lbreaderid = new Label("读者编号");TextField tf_bookid = new TextField();TextField tf_readerid = new TextField();Button queryBtn = new Button("查询");Label lbbookinfo = new Label(SepLine + "图书信息" + SepLine);Label lbbookname = new Label("图书名称：");Label tf_bookname = new Label("xx");Label lbauthor = new Label("作者：");Label tf_author = new Label("xx");Label lbpublisher = new Label("出版社：");Label tf_publisher = new Label("xx");Label lbpublish_time = new Label("出版时间：");Label tf_publish_time = new Label("xx");Label lbprice = new Label("定价：");Label tf_price = new Label("xx");Label lbstock = new Label("库存数量：");Label tf_stock = new Label("xx");Label lbreaderinfo = new Label(SepLine + "读者信息" + SepLine);Label lbreadername = new Label("读者姓名：");Label tf_readername = new Label("xx");Label lbreadertype = new Label("读者类型：");Label tf_readertype = new Label("xx");Label lbmax_num = new Label("最大可借数：");Label tf_max_num = new Label("xx");Label lbdays_num = new Label("最大可借天数：");Label tf_days_num = new Label("xx");Label lbbackinfo = new Label(SepLine + "还书信息" + SepLine);Label lbback_date = new Label("还书日期：");Label tf_back_date = new Label("xx");Button backBtn = new Button("还书");Button closeBtn = new Button("关闭");public Back() {setLayout(null);setTitle("还回图书");setSize(500, 310);this.setForeground(Color.BLACK); // 设置前景色为黑色lbbookid.setBounds(30, 40, 50, 20);// 图书编号tf_bookid.setBounds(90, 40, 90, 20);lbreaderid.setBounds(200, 40, 50, 20);// 读者编号tf_readerid.setBounds(260, 40, 90, 20);queryBtn.setBounds(370, 40, 80, 20); // 查询按钮lbbookinfo.setBounds(30, 70, 440, 20); // 图书信息提示条lbbookname.setBounds(30, 90, 60, 20); // 图书名称tf_bookname.setBounds(90, 90, 200, 20);lbauthor.setBounds(310, 90, 60, 20); // 作者tf_author.setBounds(370, 90, 90, 20);lbpublisher.setBounds(30, 110, 60, 20);// 出版社tf_publisher.setBounds(90, 110, 200, 20);lbpublish_time.setBounds(310, 110, 60, 20);// 出版时间tf_publish_time.setBounds(370, 110, 90, 20);lbprice.setBounds(30, 130, 60, 20); // 定价tf_price.setBounds(90, 130, 200, 20);lbstock.setBounds(310, 130, 60, 20); // 库存数量tf_stock.setBounds(370, 130, 90, 20);lbreaderinfo.setBounds(30, 150, 440, 20); // 读者信息提示条lbreadername.setBounds(30, 170, 60, 20); // 读者姓名tf_readername.setBounds(90, 170, 90, 20);lbreadertype.setBounds(310, 170, 60, 20); // 读者类型tf_readertype.setBounds(370, 170, 90, 20);lbmax_num.setBounds(30, 190, 75, 20); // 最大可借数tf_max_num.setBounds(105, 190, 90, 20);lbdays_num.setBounds(310, 190, 85, 20); // 最大可借天数tf_days_num.setBounds(395, 190, 70, 20);lbbackinfo.setBounds(30, 210, 440, 20); // 还书信息提示条lbback_date.setBounds(30, 230, 60, 20);// 还书日期tf_back_date.setBounds(90, 230, 100, 20);backBtn.setBounds(160, 260, 80, 25);// 还书按钮backBtn.setEnabled(false); // 开始时禁用还书按钮closeBtn.setBounds(260, 260, 80, 25);// 关闭按钮queryBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_querywActionPerformed(e);}});backBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {btn_backActionPerformed(e);}});closeBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {setForeground(Color.BLACK); // 设置前景色为黑色dispose(); // 关闭窗体}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {setForeground(Color.BLACK); // 设置前景色为黑色dispose(); // 关闭窗体}});add(lbbookid);add(lbreaderid);add(queryBtn);add(lbbookinfo);add(lbbookname);add(lbauthor);add(lbpublisher);add(lbpublish_time);add(lbprice);add(lbstock);add(lbreaderinfo);add(lbreadername);add(lbreadertype);add(lbmax_num);add(lbdays_num);add(lbbackinfo);add(lbback_date);add(backBtn);add(closeBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见setForeground(Color.RED); // 设置前景色为红色add(tf_bookid);add(tf_readerid);add(tf_bookname);add(tf_author);add(tf_publisher);add(tf_publish_time);add(tf_price);add(tf_stock);add(tf_readername);add(tf_readertype);add(tf_max_num);add(tf_days_num);add(tf_back_date);}// 图书和读者查询private void btn_querywActionPerformed(ActionEvent e) {String bookid = tf_bookid.getText();String readerid = tf_readerid.getText();// 如果图书编号或读者编号两者均为空，或者有一个为空，则返回if (bookid.equals("") || readerid.equals("")) {JOptionPane.showMessageDialog(null, "图书编号和读者编号均不能为空！");init(); // 重新初始化各参数并禁止还书按钮return;}// 按编号查询图书，结果存入book对象中Book book = BookSelect.SelectBookById(bookid);// 如果查询到结果，将其显示在各文本框中if (book != null) {tf_bookname.setText(book.getBookname());tf_author.setText(book.getAuthor());tf_publisher.setText(book.getPublisher());tf_publish_time.setText(book.getPublish_time().toString());tf_price.setText(String.valueOf((book.getPrice())));tf_stock.setText(String.valueOf(book.getStock()));} else {JOptionPane.showMessageDialog(null, "图书编号有误，查无此书！");init(); // 重新初始化各参数并禁止还书按钮return;}// 按编号查询读者，结果存入reader对象中Reader reader = ReaderSelect.selectReaderById(readerid);// 如果查询到结果，将其显示在各文本框中if (reader != null) {tf_readername.setText(reader.getReadername());tf_readertype.setText(reader.getReadertype());tf_max_num.setText(String.valueOf(reader.getMax_num()));tf_days_num.setText(String.valueOf(reader.getDays_num()));} else {JOptionPane.showMessageDialog(null, "读者编号有误，查无此人！");init(); // 重新初始化各参数并禁止还书按钮return;}// 查询指定读者是否借阅过指定图书，且未归还if (!IfBorrowBack.findbook(bookid,readerid)){JOptionPane.showMessageDialog(null, "该读者没有借过此种图书！");init(); // 重新初始化各参数并禁止还书按钮return;}SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");// 创建日期变量，其内容为当前日期Date currentdate = new Date();// 将日期按指定格式输出String borrowdate = sdf.format(currentdate);tf_back_date.setText(borrowdate);backBtn.setEnabled(true); // 使还书按钮有效}// 填写还书记录private void btn_backActionPerformed(ActionEvent e) {String sql;String bookid = tf_bookid.getText();String readerid = tf_readerid.getText();String backdate = tf_back_date.getText();// 更新borrow表记录sql = "update borrow set if_back='是',back_date='";sql = sql + backdate + "' where ";sql = sql + " book_id='" + bookid + "' and ";sql = sql + "reader_id='" + readerid + "' and ";sql = sql + "if_back='否'";DbOp.executeUpdate(sql);// 将图书库存数量加1int istock = Integer.parseInt(tf_stock.getText()) + 1;String cstock = String.valueOf(istock);// 更新画面中的图书库存数量tf_stock.setText(cstock);// 更新数据库中的图书库存数量sql = "update book set stock='" + cstock;sql = sql + "' where id='" + bookid + "'";DbOp.executeUpdate(sql);JOptionPane.showMessageDialog(null, "还书成功！");init(); // 重新初始化各参数并禁止还书按钮}// 初始化各参数项并禁止还书按钮private void init() {tf_bookname.setText("xx");tf_author.setText("xx");tf_publisher.setText("xx");tf_publish_time.setText("xx");tf_price.setText("xx");tf_stock.setText("xx");tf_readername.setText("xx");tf_readertype.setText("xx");tf_max_num.setText("xx");tf_days_num.setText("xx");tf_back_date.setText("xx");backBtn.setEnabled(false); // 禁止还书按钮}// 增加main()方法，主要为了调试程序界面public static void main(String[] args) {new Back();}
}

十、UpdatePassword.java

 　该模块用来更该当前用户的密码 。

// UpdatePassword.java
package MainPro;import java.awt.*;
import java.awt.event.*;
import javax.swing.JOptionPane;import PublicModule.*;public class UpdatePassword extends Frame {private static final long serialVersionUID = -6540483851542957663L;Label newPassword = new Label("请输入新密码");Label confirmPass = new Label("再次确认新密码");TextField text_1 = new TextField();TextField text_2 = new TextField();Button confirmBtn = new Button("确定");Button cancelBtn = new Button("取消");public UpdatePassword() {setLayout(null);setTitle("修改密码");setSize(300, 170);newPassword.setBounds(30, 50, 90, 30);text_1.setBounds(125, 53, 120, 20);confirmPass.setBounds(30, 80, 90, 30);text_2.setBounds(125, 83, 120, 20);confirmBtn.setBounds(70, 120, 70, 25); // 确定按钮confirmBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {confirmButtonPerformed(e);}});cancelBtn.setBounds(160, 120, 70, 25); // 关闭按钮cancelBtn.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {dispose(); // 释放窗体资源}});/* 关闭窗口 */this.addWindowListener(new WindowAdapter() {// 重写windowClosing()方法public void windowClosing(WindowEvent e) {dispose(); // 释放窗体资源}});add(newPassword);add(confirmPass);add(text_1);add(text_2);add(confirmBtn);add(cancelBtn);setLocationRelativeTo(null); // 使窗体在屏幕上居中放置setVisible(true); // 使窗体可见}private void confirmButtonPerformed(ActionEvent e) {System.out.println(GlobalVar.login_user);String pass1 = text_1.getText();String pass2 = text_2.getText();// 如果两个密码输入框中有一个为空，则显示错误提示信息并返回if (pass1.equals("") || pass1.equals("")) {JOptionPane.showMessageDialog(null, "密码不能为空，请重新输入！");return;}// 如果两个密码输入框中输入的内容不一致，则显示错误提示信息并返回if (!pass1.equals(pass2)) {JOptionPane.showMessageDialog(null, "两次输入的密码不一致，请重新输入！");text_1.setText("");text_2.setText("");return;}String sql = "update user set password='" + pass1+ "' where username='" + GlobalVar.login_user + "'";int i = DbOp.executeUpdate(sql);if (i == 1) {JOptionPane.showMessageDialog(null, "修改密码成功！");} elseJOptionPane.showMessageDialog(null, "用户数据库有误或不存在，修改密码失败！");}// 为了便于调试程序，特别创建main方法public static void main(String[] args) {new UpdatePassword();}
}

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