import java.io.File;

import java.util.LinkedList;

public class FileSystem {

 

 public static int num;

 

    public static void main(String[] args) {

       

        long a = System.currentTimeMillis();

        //String path="c:";

        num=0;

        String[] lists={"c:","d:"};

        /*

        for(int i=0;i<lists.length;i++){

         File file=new File(lists[i]);

         scanDirRecursion(file);

        */

        for(int i=0;i<lists.length;i++){

            scanDirNoRecursion(lists[i]);

        }

       

        System.out.print("文件总数:"+num);

        System.out.print("总耗时:");

        System.out.println(System.currentTimeMillis() - a);

    }

//非递归

    public static void scanDirNoRecursion(String path){

     LinkedList list = new LinkedList();

        File dir = new File(path);

        File file[] = dir.listFiles();

        for (int i = 0; i < file.length; i++) {

            if (file[i].isDirectory())

                list.add(file[i]);

            else{

                System.out.println(file[i].getAbsolutePath());

                num++;

            }

        }

        File tmp;

        while (!list.isEmpty()) {

            tmp = (File)list.removeFirst();//首个目录

            if (tmp.isDirectory()) {

                file = tmp.listFiles(); 

                if (file == null)

                    continue;

                for (int i = 0; i < file.length; i++) {

                    if (file[i].isDirectory())

                        list.add(file[i]);//目录则加入目录列表，关键

                    else{

                        System.out.println(file[i]);

                        num++;

                    }

                }

            } else {

                System.out.println(tmp);

                num++;

            }

        }

    }

//递归  

 public static void scanDirRecursion(File file) {

   try {

    if (file.canRead()) {

     if (file.isDirectory()) {

      String[] files = file.list();

      if (files != null) {

       for (int i = 0; i < files.length; i++) {

        scanDirRecursion(new File(file, files[i]));

       }

      }

     } else {

      //if (file.getName().endsWith("ppt"))

       System.out.println(file);

       num++;

     }

    }

   } catch (Exception e) {

    e.printStackTrace();

   }

 }

}

测试:

(1)递归： 文件总数:189497  总耗时:39328

(2)非递归：文件总数:189432 总耗时:37469

非递归相对要好