FileFilter文件过滤器

引入：将E:java目录下的所有.java文件复制到E:jad目录下，并将原来的文件的扩展名从.java改为.jad
 1 package com_2;
 2 
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.FileOutputStream;
 6 import java.io.FilenameFilter;
 7 import java.io.IOException;
 8 import java.io.InputStream;
 9 import java.io.OutputStream;
10 
11 public class Jad2Java {
12 
13     public static void main(String[] args) throws Exception {
14         // TODO Auto-generated method stub
15 
16         File srcDir = new File("E:\java");
17         if(!(srcDir.exists() && srcDir.isDirectory())){
18             throw new Exception("目录不存在");
19         }
20         File[] files = srcDir.listFiles(new FilenameFilter(){
21 
22             @Override
23             public boolean accept(File dir, String name) {
24                 
25                 return name.endsWith(".java");
26             }
27             
28         });
29         System.out.println(files.length);
30         File destDir = new File("E:\jad");
31         if(!destDir.exists()){
32             destDir.mkdir();
33         }
34         for(File f : files){
35             FileInputStream fis = new FileInputStream(f);
36             String destFileName = f.getName().replaceAll("\.java$", ".jad");
37             FileOutputStream fos = new FileOutputStream(new File(destDir,destFileName));
38             copy(fis,fos);
39             fis.close();
40             fos.close();
41         }
42 
43     }
44 
45     private static void copy(InputStream ips, OutputStream ops) throws IOException {
46         
47         int len = 0;
48         byte[] buf = new byte[1024];
49         while((len = ips.read(buf)) != -1){
50             ops.write(buf,0,len);
51         }
52         
53     }
54     
55 }