list排序

package test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class TestSort {
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.getAge() != s2.getAge()) {
                return s1.getAge() - s2.getAge();
            } else if (!s1.getStudentName().equals(s2.getStudentName())) {
                // 年龄相同则按姓名排序
                return s1.getStudentName().compareTo(s2.getStudentName());
            } else {
                // 姓名也相同则按学号排序
                return s1.getStudentId() - s2.getStudentId();
            }
        }
    };
     Student stu1 = new Student (1,"zhangsan",28);
     Student stu2 = new Student (2,"zhagnsan",19);
     Student stu3 = new Student (3,"wangwu",19);
     Student stu4 = new Student (4,"wangwu",19);
     Student stu5 = new Student (5,"zhaoliu",18);

      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);
      for(int i=0;i<list.size();i++){
          Student stu=list.get(i);
          System.out.println("年龄:"+stu.getAge()+"   姓名:"+stu.getStudentName()+"   学号:"+stu.getStudentId());
      }

}
}