以文件最后修改时间顺序复制文件

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Date;

public class aa {
 /**
  * 复制整个文件夹内容,并替换所有文件中的";"
  *
  * @param oldPath
  *            String 原文件路径 如：e:/b/
  * @param newPath
  *            String 复制后路径 如：e:/a/
  */
 public void copyFolder(String oldPath, String newPath) {

  try {
   File filePath = new File(oldPath);
   String[] file = filePath.list();
            int len =file.length;
   for (int i = 0; i < len; i++) {

    File temp = this.getLastTimeFile(oldPath, newPath);
    System.out.println("**********");
    if (temp.isFile()) {
     this.writeFile(this.readerFile(temp.toString()), newPath
       + "/" + (temp.getName()).toString());
     temp.delete();
    }    
   }
   System.out.println("复制文件夹操作 成功执行");
  } catch (Exception e) {
   System.out.println("复制整个文件夹内容操作出错");
   e.printStackTrace();

  }
 }

 public String readerFile(String filePath) {
  String a = "";
  File f = new File(filePath);
  if (f.exists()) {
   try {
    // 下为读取文件
    BufferedReader raf = new BufferedReader(
      new FileReader(filePath));
    char[] buf = new char[1024*5];
    int len = raf.read(buf);
    a = new String(buf, 0, len);
    raf.close();
   } catch (Exception e) {
    e.printStackTrace();
   }
  }
  return a.replaceAll(";", " ");
 }

 public static void writeFile(String content, String filePath) {
  BufferedWriter bw = null;
  try {
   bw = new BufferedWriter(new FileWriter(filePath));
   bw.write(content);
   bw.flush();
  } catch (Exception e) {
   e.printStackTrace();

  } finally {
   if (bw != null) {
    try {
     bw.close();
    } catch (Exception ex) {

    }
    bw = null;
   }
  }
 }

 public File getLastTimeFile(String oldPath, String newPath) {

  File temp0 = null;
  File temp1 = null;
  try {
//   (new File(newPath)).mkdirs();
   File filePath = new File(oldPath);
   String[] file = filePath.list();

   for (int i = 0; i < file.length; i++) {
    for (int j = 0; j <file.length; j++) {
     if (oldPath.endsWith(File.separator)) {
      temp0 = new File(oldPath + file[i]);
      temp1 = new File(oldPath + file[j]);
     } else {
      temp0 = new File(oldPath + File.separator + file[i]);
      temp1 = new File(oldPath + File.separator + file[j]);
     }

     
      if (temp1.isFile()) {
       Date date0 = new Date(temp0.lastModified());
       Date date1 = new Date(temp1.lastModified());
       if (date0.after(date1)) {
        temp0 = temp1;
        
       }
      }
    

    
    }
    if (temp0.isDirectory()) {// 如果是子文件夹
     copyFolder(oldPath + "/" + file[i], newPath + "/"
       + file[i]);
    }
   }
   System.out.println("得到修改时间最晚的文件");
  } catch (Exception e) {
   System.out.println("复制整个文件夹内容操作出错");
   e.printStackTrace();
  }
       
  return temp0;
 }

 public static void main(String[] args) {
  aa a = new aa();
  a.copyFolder("e:/b/", "e:/a/");
 }
}