使用java 如何实现一个文件夹拷贝功能

import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;public class CopyFile {  public static void copy(String sourceFile , String targetFile) throws Exception{    FileInputStream in = null;    FileOutputStream out = null;    try{      in = new FileInputStream(new File(sourceFile));      out = new FileOutputStream(new File(targetFile));      int c;      while ((c = in.read()) != -1 ){        out.write(c);      }    }    finally{      if (in != null){        in.close();      }      if(out != null){        out.close();      }    }  }  public static void main(String[] agrs) throws Exception{    String filedir = "./tupu0";    String targetDir = "./MovieList/";    File directory = new File(filedir);    File[] fileList = directory.listFiles();    for(int i=0; i<fileList.length; i++){      String sourceFile = "./tupu0/" + fileList[i].getName() + "/" + fileList[i].getName() +".txt";      String targetFile = targetDir + fileList[i].getName();      System.out.println(fileList[i].getName());      copy(sourceFile, targetFile);    }  }}