编写一个程序，将d:\java目录下的所有.java文件复制到d:\jad目录下，并将原来文件的扩展名从.java改为. jad

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.FilenameFilter;

import java.io.IOException;

public class CopyFolderTest {

    public static void main(String[] args) throws IOException {

      // 封装数据源和目的地

      File file1 = new File("d:\\Java");

      File file2 = new File("d:\\jad");

     // 文件过滤器封装目录下String数组对象,匿名对象

     String[] strArr = file1.list(new  FilenameFilter() {

        @Override

        public boolean  accept(File dir, String name) {

        // 判断条件文件和后缀

          return new File(dir, name).isFile() && name. endsWith(".java");

       }

      });

      // 遍历

      for (String str : strArr) {

        // 输入流,封装符合条件的数据源

        BufferedReader br = new BufferedReader(new FileReader(

                                    new File(file1, str)));

        // 输出流,改名并封装要装入的目的地

        BufferedWriter bw = new BufferedWriter(new FileWriter(

        new File(file2, str. replace(".java", ".jad"))));

        // 遍历读写文件

        String line = null;

        while ((line = br.readLine()) != null) {

               bw.write(line);

               bw.newLine();

               bw.flush();

          }

          br.close();

          bw.close();

     }

   }

}