编程实现文件复制和重命名

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。

package com.alex.test3;import java.io.File;import java.io.FileFilter;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;public class Java2Jad {/** * @param args * @throws Exception  */public static void main(String[] args) throws Exception {File javaFile = new File("D:\\java");File[] javaFiles=null;if(javaFile.exists()&&javaFile.isDirectory()){javaFiles=javaFile.listFiles(new FileFilter(){public boolean accept(File pathname) {return pathname.getName().endsWith(".java");}});copyAndRenameFiles(javaFiles,"D:\\jad","\\.java",".jad");System.out.println("copy successful...");}else{throw new Exception("there are not such directroy");}}public static void copyAndRenameFiles(File[] sourceFiles,String targetFilePath,String originalSuffix,String targetSuffix){File targetFile = new File(targetFilePath);FileWriter fw = null;FileReader fr = null;if(!targetFile.isDirectory()){targetFile.mkdir();}try {for(File file:sourceFiles){fw = new FileWriter(targetFilePath+"\\"+file.getName().replaceAll(originalSuffix, targetSuffix));int len=0;char[] cbuf=new char[(int)file.length()];fr = new FileReader(file);while((len=fr.read(cbuf))!=-1){fw.write(cbuf,0,len);}}fw.close();} catch (IOException e) {e.printStackTrace();}}}