public String[] list(FilenameFilter filter):
public File[] listFiles(FilenameFilter filter):
FilenameFilter是接口，所以需要找他的实现类

//指定文件目录
		File f=new File("E:\\");
		
		//public String[] list(FilenameFilter filter):
		String[] strarray=f.list(new FilenameFilter(){

			@Override
			public boolean accept(File dir, String name) {
				// TODO Auto-generated method stub

				//System.out.println(dir+"---"+name);//返回的是目录和文件名
				File file=new File(dir,name);
				boolean flag=file.isFile();//如果是文件
				boolean flag2=name.endsWith(".txt");
				return flag && flag2;
			}
			
		});
		
		for(String s:strarray){
			System.out.println(s);
		}