1 FileReader  fr =new FileReader("b.txt");//绑定源文件
 2 FileWriter  fw= new FileWriter("a.txt");
 3 char[]  c= new char[1024];
 4 int  len=0;
 5 //循环读取
 6 while((len=fr.read(c))!=-1){   
 7     fw.write(c,0,len);
 8                 
 9 }
10 //关流
11 fw.close();
12 fr.close();