小编cod*_*123的帖子

我想根据id和标记对对数据进行排序.ID应按升序排列,标记应按降序排列,这是我的代码:

ArrayList<Student> al=new ArrayList<Student>();
    al.add(new Student(1,"dg",58));
    al.add(new Student(2,"dg",48));
    al.add(new Student(1,"dg",98));
    al.add(new Student(2,"dg",68));
    al.add(new Student(1,"dg",38));
    al.add(new Student(2,"dg",28));
    al.add(new Student(2,"dg",90));    

输出如:

1 dg 98  
1 dg 58  
1 dg 38  
2 dg 90  
2 dg 68  
2 dg 48  
2 dg 28