java实现按照文件的修改时间排序文件夹下的文件

    public int compare(Object o1, Object o2) {        File file1 = (File)o1;        File file2 = (File)o2;        long diff = file1.lastModified() - file2.lastModified();        if (diff > 0)            return 1;        else if (diff == 0)            return 0;        else            return -1;    }    public boolean equals(Object obj){        return true; //简单做法    }