Java如何实现List自定义排序

实体类

package com.whty.entity;

public class User {
private int id;
private String name;
private int age;

public User(int id, String name, int age) {
super();
this.id = id;
this.name = name;
this.age = age;
}

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}

@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}

测试类

package com.whty.test;

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

import com.whty.entity.User;

public class Test {
public static void main(String[] args) {
List<User> list = new ArrayList<>();
list.add(new User(1, "java", 20));
list.add(new User(2, "spark", 19));
list.add(new User(3, "hive", 21));

for(User user :list) {
System.out.println("排序前：" + user.toString());
}
//实现排序
Collections.sort(list, new Comparator<User>() {
@Override
public int compare(User u1, User u2) {
if(u1.getAge() > u2.getAge()) {
//return -1:即为正序排序
return -1;
}else if (u1.getAge() == u2.getAge()) {
return 0;
}else {
//return 1: 即为倒序排序
return 1;
}
}
});

for(User user :list) {
System.out.println("排序后：" + user.toString());
}
}
}

运行结果

排序前：User [id=1, name=java, age=20]
排序前：User [id=2, name=spark, age=19]
排序前：User [id=3, name=hive, age=21]
排序后：User [id=3, name=hive, age=21]
排序后：User [id=1, name=java, age=20]
排序后：User [id=2, name=spark, age=19]

来源：https://cloud.tencent.com/developer/article/1639912