1 import java.io.*;
  2 public class WRDemo
  3 {
  4     public static void main(String[] args) throws IOException
  5     {
  6         //实例化WriterFile和ReaderFile对象
  7         WriterFile w=new WriterFile();
  8         ReaderFile r=new ReaderFile();
  9         //声明两个文件读入流
 10         FileInputStream in1=null,in2=null;
 11         File inputFile=null;
 12         try {
 13                 String [] filename={"d:\\java_test\\1.txt","d:\\java_test\\2.txt","d:\\java_test\\12.txt"};
 14                 for(int i=0;i<filename.length-1;i++)
 15                 {
 16                     inputFile=new File(filename[i]);
 17                     if(inputFile.exists())
 18                     {
 19                         System.out.println(inputFile.getName()+"文件存在！删除重新建立文件");
 20                         inputFile.delete();
 21                         w.run(inputFile,i+1);
 22                         if(i==0)
 23                             in1=r.run(inputFile);
 24                         if(i==1)
 25                             in2=r.run(inputFile);
 26                     }
 27                     else {
 28                         System.out.println(inputFile.getName()+"文件不存在！创建文件");
 29                         w.run(inputFile,i+1);
 30                         if(i==0)
 31                             in1=r.run(inputFile);
 32                         if(i==1)
 33                             in2=r.run(inputFile);
 34                     }
 35                 }
 36                 //构造一个输出文件
 37                 File outputfile=new File(filename[2]);
 38                 //将两个文件合为一个输入流
 39                 w.run1(in1,in2,outputfile);
 40                 System.out.println("ok...");
 41                 in1.close();
 42                 in2.close();
 43
 44             }
 45             catch (IOException ex) {
 46                 ex.printStackTrace();
 47             }
 48             finally{
 49                 if(in1!=null)
 50                     try
 51                     {
 52                         in1.close();
 53                     }
 54                     catch (IOException ex)
 55                     {
 56                         ex.printStackTrace();
 57                     }
 58                     if(in2!=null)
 59                     try
 60                     {
 61                         in2.close();
 62                     }
 63                     catch (IOException ex)
 64                     {
 65                         ex.printStackTrace();
 66                     }
 67             }
 68     }
 69 }
 70 class WriterFile
 71 {
 72     public FileOutputStream run(File f,int i)
 73     {
 74         //构造一个输出流
 75         FileOutputStream out=null;
 76         try {
 77             out=new FileOutputStream(f);
 78         }
 79         catch (IOException ex) {
 80             ex.printStackTrace();
 81         }
 82         String str="我是第"+i+"个文件"+i+".txt"+"\r\n"; //这两个转义字符在Windows系统中代表换行"\r\n"
 83         System.out.println("向第"+i+"个文件写入:\r\n"+str);
 84         byte[] f1=str.getBytes();
 85         try {
 86                 //将str写入文件
 87                 out.write(f1);
 88                 out.close();
 89         }
 90         catch (IOException ex) {
 91                 ex.printStackTrace();
 92         }
 93          94     }
 95     public void run1(FileInputStream in1,FileInputStream in2,File outputFile)
 96     {
 97         SequenceInputStream s=null;
 98         FileOutputStream out=null;
 99         try
100         {
101             s=new SequenceInputStream(in1,in2);
102             out=new FileOutputStream(outputFile);
103             int c;
104             while((c=s.read())!=-1)
105                 out.write(c);
106             s.close();
107             out.close();
108         }
109         catch (IOException ex)
110         {
111             ex.printStackTrace();
112         }
113         finally {
114             if(s!=null)
115             try
116             {
117                 s.close();
118             }
119             catch (IOException ex)
120             {
121                 ex.printStackTrace();
122             }
123             if(out!=null)
124             try
125             {
126                 out.close();
127             }
128             catch (IOException ex)
129             {
130                 ex.printStackTrace();
131             }
132         }
133     }
134 }
135
136 class ReaderFile
137 {
138     public FileInputStream  run(File f)
139     {
140         //声明一个文件读入流
141         FileInputStream in =null;
142         try {
143             in=new FileInputStream(f);
144             in.close();
145         }
146         catch (IOException ex) {
147             ex.printStackTrace();
148         }
149         finally{
150             if(in!=null)
151                 try {
152                  in.close();
153                 }
154                 catch (IOException ex) {
155                 ex.printStackTrace();
156                 }
157         }
158         return in;
159     }
160 }