查找一个目录下的所有文件

package test1;

import java.io.File;
import java.util.LinkedList;

public class FileSystem {
public static void main(String[] args) {
long a = System.currentTimeMillis();
LinkedList list = new LinkedList();
File dir = new File("file");
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());
}
File tmp;
while (!list.isEmpty()) {
tmp = (File) list.removeFirst();
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]);
else
System.out.println(file[i].getAbsolutePath());
}
} else {
System.out.println(tmp.getAbsolutePath());
}
}

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