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

package com_2;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class Jad2Java {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub

        File srcDir = new File("E:\java");
        if(!(srcDir.exists() && srcDir.isDirectory())){
            throw new Exception("目录不存在");
        }
        File[] files = srcDir.listFiles(new FilenameFilter(){

            @Override
            public boolean accept(File dir, String name) {
                
                return name.endsWith(".java");
            }
            
        });
        System.out.println(files.length);
        File destDir = new File("E:\jad");
        if(!destDir.exists()){
            destDir.mkdir();
        }
        for(File f : files){
            FileInputStream fis = new FileInputStream(f);
            String destFileName = f.getName().replaceAll("\.java$", ".jad");
            FileOutputStream fos = new FileOutputStream(new File(destDir,destFileName));
            copy(fis,fos);
            fis.close();
            fos.close();
        }

    }

    private static void copy(InputStream ips, OutputStream ops) throws IOException {
        
        int len = 0;
        byte[] buf = new byte[1024];
        while((len = ips.read(buf)) != -1){
            ops.write(buf,0,len);
        }
        
    }
    
}