java如何对ArrayList中对象按照该对象某属性排序

来源：互联网发布：php判断是不是正整数编辑：程序博客网时间：2024/05/18 13:24

以下是一个student类的一个例子，用的是Collections.sort();方法，可以自己贴过去运行一下就清楚了

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; }}

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