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