JSP增删改查及分页

我的界面大概是这个样子，简单版本，没美化，数据库用的sqlserver，建立三个表学生表、教员表、班级表

1.增加

1.1增加是个a标签，下面是增加界面

1.2确定按钮提交表单，增加成功存到数据库，否则回到主界面

1.3重置按钮可清空表格所填信息按钮属性type="reset" 即可做到

2.删除

2.1根据学生id删除

2.2删除时弹出一个提示框，可取消删除，用到js的comfirm提示框

2.3取消和删除后会回到主界面，并且删除后提示删除成功

3.修改

3.1修改界面与增加界面一致

3.2点击修改时需要把id传到servlet中查询对应的学生

3.3然后将查询到的学生传到界面显示信息

3.4复选框的回显：将爱好根据逗号切割（split（））成为一个数组，遍历该数组，对每个复选框进行判断，遍历的值与复选框的值一致则默认选中，具体操作看下面代码

servlet：

package com.Servlet;import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.dao.StudentDao;
import com.entity.student;
@WebServlet("/updshow.do")
public class UpdShowServlet extends HttpServlet{protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf-8");resp.setContentType("text/html;charset=utf-8");int sid = Integer.parseInt(req.getParameter("sid"));student s = new StudentDao().byids(sid);String sah = s.getSah();//切割String[] split = sah.split(",");req.setAttribute("s", s);req.setAttribute("split", split);req.getRequestDispatcher("upd.jsp").forward(req, resp);}}

jsp：

4.分页模糊查询

sqlserver的分页语句：

select * from (select *,row_number() over(order by sid) as rowid from student
)as b where rowid between 1 and 3

4.1模糊查询的关键字有三个：教员班级爱好

4.2教员和班级为下拉框默认选中第一个，爱好可勾选可不勾选不勾选时默认为空字符串，勾选时通过逗号拼接起来进行模糊查询

4.3查询后默认分页，我这里是两条一页，点下一页时将下一页的页数和模糊查询的关键字传到servlet中

4.4输入框分页：根据输入的页码跳转界面，我这里是用表单将输入框的GO按钮装起来，点击go提交表单，关键字通过隐藏的输入框带过去进行查询，具体操作看下面代码

4.5首页和尾页的跳转，就是将1和最大的页码数和关键字信息传到servlet中


<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style type="text/css">
#t1{
margin: auto;
text-align: center;
width: 600px;
height: 300px
}
table,tr,td{
border-collapse: collapse;
}
#inp{
text-align: center;
}
#p{
text-align: center;
}
#but{
background-color: orange;
}
#go{
border: none;
}
</style>
</head>
<body>
<form action="key.do">
<div id="inp"><button id="but">查询</button>&nbsp;<a href="add.jsp">新增</a></div>
<table border="" id="t1">
<tr>
<td colspan="6">
教员:
<select name="teacher">
<c:forEach var="i" items="${ allT }">
<option value="${ i.tname }" ${ i.tname==teacher?"selected":"" }>${ i.tname }</option>
</c:forEach>
</select>
班级:
<select name="sclass">
<c:forEach var="i" items="${ allC }">
<option value="${ i.sclazz }" ${ i.sclazz==sclass?"selected":"" }>${ i.sclazz }</option>
</c:forEach>
</select>
爱好:
<input type="checkbox" name="ah" value="篮球" <c:forEach var="i" items="${ split }">
<c:if test="${ i=='篮球' }"> checked
</c:if>
</c:forEach>
>篮球
<input type="checkbox" name="ah" value="唱歌" <c:forEach var="i" items="${ split }">
<c:if test="${ i=='唱歌' }"> checked
</c:if>
</c:forEach>
>唱歌
<input type="checkbox" name="ah" value="足球" <c:forEach var="i" items="${ split }">
<c:if test="${ i=='足球' }"> checked
</c:if>
</c:forEach>
>足球
<input type="checkbox" name="ah" value="跳舞" <c:forEach var="i" items="${ split }">
<c:if test="${ i=='跳舞' }"> checked
</c:if>
</c:forEach>
>跳舞
</td>
</tr>
</form>
<tr>
<td>学生ID</td>
<td>学生姓名</td>
<td>学生教员</td>
<td>班级</td>
<td>学生爱好</td>
<td>操作</td>
</tr>
<c:forEach var="i" items="${ list }">
<tr>
<td>${ i.sid }</td>
<td>${ i.sname }</td>
<td>${ i.tname }</td>
<td>${ i.sclass }</td>
<td>${ i.sah }</td>
<td><a href="del.do?sid=${ i.sid }">删除</a><a href="updshow.do?sid=${ i.sid }">修改</a></td>
</tr>
</c:forEach>
</table>
<div id="p">第${ pages }页，共${ max }页，总记录${ m }条，
<a href="key.do?aid=1&teacher=${ teacher }&sclass=${ sclass }&ah=${ ah }">首页</a>，
<a href="key.do?aid=${ pages-1<1?1:pages-1 }&teacher=${ teacher }&sclass=${ sclass }&ah=${ ah }">上一页</a>，
<form action="key.do"><input style="width: 20px" name="aid">
<input style="width: 20px" name="teacher" value="${ teacher }" type="hidden">
<input style="width: 20px" name="sclass" value="${ sclass }" type="hidden">
<input style="width: 20px" name="ah" value="${ ah }" type="hidden">
<button id="go">Go</button></form>,
<a href="key.do?aid=${ pages+1>max?max:pages+1 }&teacher=${ teacher }&sclass=${ sclass }&ah=${ ah }">下一页</a>，
<a href="key.do?aid=${ max }&teacher=${ teacher }&sclass=${ sclass }&ah=${ ah }">尾页</a></div>
</body>
</html>

注意：模糊查询的分页和进入主界面的没有模糊查询的分页参数不能相同，不然会分页错误哦！我用的是pid和aid

5.dao包所有方法

每个方法都有注释

package com.dao;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;import com.entity.clazz;
import com.entity.student;
import com.entity.teacher;
import com.util.DBHelper;/*** 方法类* @author zjjt**/
public class StudentDao {/*** 查询全部学生* @return*/public List<student> getAll(){List<student> list = new ArrayList<student>();Connection con=DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("select * from student");rs = ps.executeQuery();while (rs.next()) {student s=new student();s.setSid(rs.getInt(1));s.setSname(rs.getString(2));s.setSah(rs.getString(3));s.setSclass(rs.getString(4));s.setTname(rs.getString(5));list.add(s);}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return list;}/*** 查询所有教员*/public List<teacher> getAllT(){List<teacher> list = new ArrayList<teacher>();Connection con=DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("select * from teacher");rs = ps.executeQuery();while (rs.next()) {teacher t=new teacher();t.setTid(rs.getInt(1));t.setTname(rs.getString(2));list.add(t);}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return list;}/*** 查询所有班级*/public List<clazz> getAllC(){List<clazz> list = new ArrayList<clazz>();Connection con=DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("select * from clazz");rs = ps.executeQuery();while (rs.next()) {clazz c=new clazz();c.setCid(rs.getInt(1));c.setSclazz(rs.getString(2));list.add(c);}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return list;}/*** 主界面的分页* @param pages* @param pagesize* @return*/public List<student> getpage(int pages,int pagesize){List<student> list = new ArrayList<student>();Connection con=DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("select * from (select *,row_number() over(order by sid) as rowid from student)as b where rowid between ? and ?");ps.setInt(1, pages);ps.setInt(2, pagesize);rs = ps.executeQuery();while (rs.next()) {student s=new student();s.setSid(rs.getInt(1));s.setSname(rs.getString(2));s.setSah(rs.getString(3));s.setSclass(rs.getString(4));s.setTname(rs.getString(5));list.add(s);}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return list;}/*** 模糊查询的分页* @param pages* @param pagesize* @param key1* @param key2* @param key3* @return*///爱好  班级  教员public List<student> getpage(int pages,int pagesize,String key1,String key2,String key3){List<student> list = new ArrayList<student>();Connection con=DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("\r\n" + "select * from (select *,row_number() over(order by sid) as rowid from student\r\n" + "where sah like ? \r\n" + "and sclass like ? and tname like ?\r\n" + ")as b where rowid between ? and ?");ps.setInt(4, pages);ps.setInt(5, pagesize);ps.setString(1, "%"+key1+"%");ps.setString(2, "%"+key2+"%");ps.setString(3, "%"+key3+"%");rs = ps.executeQuery();while (rs.next()) {student s=new student();s.setSid(rs.getInt(1));s.setSname(rs.getString(2));s.setSah(rs.getString(3));s.setSclass(rs.getString(4));s.setTname(rs.getString(5));list.add(s);}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return list;}/*** 删除学生* @param sid* @return*/public int del(int sid) {Connection con=DBHelper.getCon();PreparedStatement ps=null;try {ps=con.prepareStatement("delete from student where sid=?");ps.setInt(1, sid);return ps.executeUpdate();} catch (Exception e) {e.printStackTrace();}finally {DBHelper.myClose(con, ps, null);}return 0;}/*** 增加学生* @param s* @return*/public int add(student s) {Connection con=DBHelper.getCon();PreparedStatement ps=null;try {ps=con.prepareStatement("insert into student values(?,?,?,?)");ps.setString(1, s.getSname());ps.setString(2, s.getSah());ps.setString(3, s.getSclass());ps.setString(4, s.getTname());return ps.executeUpdate();} catch (Exception e) {e.printStackTrace();}finally {DBHelper.myClose(con, ps, null);}return 0;}/*** 根据ID查询学生* @param sid* @return*/public student byids(int sid) {Connection con = DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("select * from student where sid=?");ps.setInt(1, sid);rs = ps.executeQuery();while (rs.next()) {student s=new student();s.setSid(rs.getInt(1));s.setSname(rs.getString(2));s.setSah(rs.getString(3));s.setSclass(rs.getString(4));s.setTname(rs.getString(5));return s;}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return null;}/*** 修改学生信息* @param s* @return*/public int upd(student s) {Connection con=DBHelper.getCon();PreparedStatement ps=null;try {ps=con.prepareStatement("update student set sname=?,sah=?,sclass=?,tname=? where sid=?");ps.setString(1, s.getSname());ps.setString(2, s.getSah());ps.setString(3, s.getSclass());ps.setString(4, s.getTname());ps.setInt(5, s.getSid());return ps.executeUpdate();} catch (Exception e) {e.printStackTrace();}finally {DBHelper.myClose(con, ps, null);}return 0;}/*** 模糊查询* @param key1* @param key2* @param key3* @return*/public List<student> getkey(String key1,String key2,String key3){List<student> list = new ArrayList<student>();Connection con=DBHelper.getCon();PreparedStatement ps = null;ResultSet rs = null;try {ps = con.prepareStatement("select * from student where tname like ? and sclass like ? and sah like ?");ps.setString(1, "%"+key1+"%");ps.setString(2, "%"+key2+"%");ps.setString(3, "%"+key3+"%");rs = ps.executeQuery();while (rs.next()) {student s=new student();s.setSid(rs.getInt(1));s.setSname(rs.getString(2));s.setSah(rs.getString(3));s.setSclass(rs.getString(4));s.setTname(rs.getString(5));list.add(s);}} catch (Exception e) {e.printStackTrace();} finally {DBHelper.myClose(con, ps, rs);}return list;}}

模糊查询的servlet

package com.Servlet;import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.dao.StudentDao;
import com.entity.student;
@WebServlet("/key.do")
public class KeyServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);
}
@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf-8");resp.setContentType("text/html;charset=utf-8");String teacher= req.getParameter("teacher");String sah="";String[] ah = req.getParameterValues("ah");if(ah==null) {sah="";}else {for (String s : ah) {sah+=s+",";}}String[] split = sah.split(",");String sclass = req.getParameter("sclass");String aid = req.getParameter("aid");int pages=1;if(aid!=null) {pages=Integer.parseInt(aid);}int pagesize=2;int begin=(pages-1)*pagesize+1;int end=pages*pagesize;int m=new StudentDao().getkey(teacher, sclass, sah).size();List<student> list2 = new StudentDao().getkey(teacher,sclass,sah);List<student> list = new StudentDao().getpage(begin,end,sah,sclass,teacher);//最大页码数int max=(int)Math.ceil(m*1.0/pagesize);req.setAttribute("list", list);req.setAttribute("max", max);req.setAttribute("pages", pages);req.setAttribute("teacher", teacher);req.setAttribute("sah", sah);req.setAttribute("m", m);req.setAttribute("split", split);req.setAttribute("sclass", sclass);req.getRequestDispatcher("mohu.jsp").forward(req, resp);
}
}

JSP增删改查大概就涉及到这些内容，不懂的可私信哦！