有几个方法可以实现：让 Student 实现Comparable接口，或是实例化一

个比较器，

现在用 Comparator 比较器实例来做一个：ComparableTest.java

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

public class ComparableTest {

public static void main(String[] args) {

  Comparator<Student> comparator = new Comparator<Student>(){

   public int compare(Student s1, Student s2) {

    //先排年龄

    if(s1.age!=s2.age){

     return s1.age-s2.age;

    }

    else{

     //年龄相同则按姓名排序

     if(!s1.name.equals(s2.name)){

      return s1.name.compareTo(s2.name);

     }

     else{

      //姓名也相同则按学号排序

      return s1.id-s2.id;

     }

    }

   }

  };

  Student stu1 = new Student (1,"zhangsan","male",28,"cs");

  Student stu2 = new Student (2,"lisi","female",19,"cs");

  Student stu3 = new Student (3,"wangwu","male",22,"cs");

  Student stu4 = new Student (4,"zhaoliu","female",17,"cs");

  Student stu5 = new Student (5,"jiaoming","male",22,"cs");

  ArrayList<Student> List = new ArrayList<Student>();

  List.add(stu1);

  List.add(stu2);

  List.add(stu3);

  List.add(stu4);

  List.add(stu5); 

  //这里就会自动根据规则进行排序

  Collections.sort(List,comparator);

  display(List);

}

static void display(ArrayList<Student> lst){

  for(Student s:lst)

   System.out.println(s);

}

}

class Student{

int age;

int id;

String gender;

String name;

String cs;

Student(int id,String name,String gender,int age,String cs){

  this.age=age;

  this.name=name;

  this.gender=gender;

  this.id=id;

  this.cs=cs;

}

public String toString(){

  return id+"  "+name+"  "+gender+"  "+age+"  "+cs;

}