import java.io.File;

import java.io.FilenameFilter;

public class FileByJava implements FilenameFilter{

    public boolean accept(File dir, String name) {

        //System.out.println("dir....."+name);//先全部遍历，然后再过滤

        return name.endsWith(".java");//表示过滤.java的文件

    }

}

import java.io.File;

public class ListDemo {

    public static void main(String[] args) {

        listDemo();

    }

    public static void listDemo() {

        File dir = new File("F:\\");

        String[] name = dir.list(new FileByJava());

        for(String names : name){

            System.out.println(names);

        }

    }

}