import java.io.*;

题目

import java.io.*;
public class FileFilterTest {
public static void main(String args[]){
File dir=new File("/dongl");
Filter filter=new Filter("htm");
System.out.println("list html files in directory"+dir);
String files[]=dir.list(filter);
for(int i=0;i

答案

File(String extent)
改为
Filter (String extent)