List集合对象中按照不同属性大小排序的实例
作者:jingxian 时间:2023-06-07 14:27:41
实例如下:
package com.huad.luck;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class Test {
public static void main(String[] args) {
Person p = new Person();
p.setName("tom");
p.setAge(11);
Person p1 = new Person();
p1.setName("lilei");
p1.setAge(19);
Person p2 = new Person();
p2.setName("json");
p2.setAge(15);
List<Person> list =new ArrayList<Person>();
list.add(p);
list.add(p1);
list.add(p2);
Collections.sort(list,new Comparator<Person>() {
//这里可以再Person中实现 Comparator<T>接口,重写compare方法
@Override
public int compare(Person o1, Person o2) {
//这里按照名字排序
return o1.getName().compareTo(o2.getName());
//这里按照age排序
//return (o1.getAge()+"").compareTo(o2.getAge()+"");
//。。。根据不同属性值排序
}
});
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i).getName());
}
}
}
//Person类
package com.huad.luck;
public class Person{
private String name ;
private int age;
public Person(String name , int age) {
this.name = name;
this.age = age;
}
public Person( ) {
}
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;
}
}
<p style="padding-top: 0px; padding-bottom: 0px; margin-top: 8px; margin-bottom: 8px; line-height: 22.5px; letter-spacing: 0.5px; font-size: 12.5px; word-wrap: break-word; word-break: break-all; color: rgb(51, 51, 51); font-family: 'Microsoft YaHei', Verdana, sans-serif, 宋体;"><span style="padding: 0px; margin: 0px; letter-spacing: normal; font-stretch: normal; font-size: 14px; line-height: 24px; font-family: Tahoma; color: rgb(0, 0, 0);">用collection.sort()方法对list集合排序</span><br style="padding: 0px; margin: 0px;" /></p><p style="padding-top: 0px; padding-bottom: 0px; margin-top: 0px; margin-bottom: 0px; line-height: 24px; font-size: 14px; word-wrap: break-word; word-break: break-all; font-stretch: normal; font-family: Tahoma;"><span style="padding: 0px; margin: 0px; list-style: none outside none; word-wrap: break-word; word-break: normal;"><span style="padding: 0px; margin: 0px; list-style: none outside none; line-height: 21px; word-wrap: break-word; word-break: normal;"></span></span></p><p style="padding-top: 0px; padding-bottom: 0px; margin-top: 1em; margin-bottom: 0.5em; line-height: 24px; font-size: 14px; word-wrap: break-word; word-break: break-all; font-stretch: normal; font-family: Tahoma;">第一种是list中的对象实现Comparable接口,如下:<span style="padding: 0px; margin: 0px; list-style: none outside none; word-wrap: break-word; word-break: normal;"> </span></p><pre class="java" style="padding: 5px; margin-top: 0px; margin-bottom: 0px; line-height: 18px; font-size: 9pt; font-family: 'Courier New', Arial; border: 1px solid rgb(221, 221, 221); color: rgb(51, 51, 51); background: rgb(246, 246, 246);">/**
* 根据order对User排序
*/
public class User implements Comparable<User>{
private String name;
private Integer order;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getOrder() {
return order;
}
public void setOrder(Integer order) {
this.order = order;
}
public int compareTo(User arg0) {
return this.getOrder().compareTo(arg0.getOrder());
}
}
测试一下:
public class Test{
public static void main(String[] args) {
User user1 = new User();
user1.setName("a");
user1.setOrder(1);
User user2 = new User();
user2.setName("b");
user2.setOrder(2);
List<User> list = new ArrayList<User>();
//此处add user2再add user1
list.add(user2);
list.add(user1);
Collections.sort(list);
for(User u : list){
System.out.println(u.getName());
}
}
}
输出结果如下
a
b
第二种方法是根据Collections.sort重载方法来实现,例如:
/**
* 根据order对User排序
*/
public class User { //此处无需实现Comparable接口
private String name;
private Integer order;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getOrder() {
return order;
}
public void setOrder(Integer order) {
this.order = order;
}
}
主类中这样写即可:
public class Test{
public static void main(String[] args) {
User user1 = new User();
user1.setName("a");
user1.setOrder(1);
User user2 = new User();
user2.setName("b");
user2.setOrder(2);
List<User> list = new ArrayList<User>();
list.add(user2);
list.add(user1);
Collections.sort(list,new Comparator<User>(){
public int compare(User arg0, User arg1) {
return arg0.getOrder().compareTo(arg1.getOrder());
}
});
for(User u : list){
System.out.println(u.getName());
}
}
}
输出结果如下
a
b
前者代码结构简单,但是只能根据固定的属性排序,后者灵活,可以临时指定排序项,但是代码不够简洁
多字段的场合:
Collections.sort(list,new Comparator<User>(){
public int compare(User arg0, User arg1) {
// 第一次比较专业
int i = arg0.getOrder().compareTo(arg1.getOrder());
// 如果专业相同则进行第二次比较
if(i==0){
// 第二次比较
int j=arg0.getXXX().compareTo(arg1.getXXX());
// 如果学制相同则返回按年龄排序
if(j==0){
return arg0.getCCC().compareTo(arg1.getCCC());
}
return j;
}
return i;
}
});
以下是另外一个例子
package test;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
public class ArrayListTest {
public static void main(String[] args) {
ArrayList<Exmployee> arrayList = new ArrayList<Exmployee>() ;
arrayList.add(new Exmployee("zengqiang",new Integer(5000))) ;
arrayList.add(new Exmployee("zengmin",new Integer(4000))) ;
arrayList.add(new Exmployee("liuxiaojuan",new Integer(4200))) ;
arrayList.add(new Exmployee("giuming",new Integer(2200))) ;
Collections.sort(arrayList, new Comparator<Exmployee>(){
public int compare(Exmployee arg0, Exmployee arg1) {
return arg1.getSalary()-arg0.getSalary() ; //按照工资升序
//return arg0.getSalary()-arg1.getSalary() ; 按照工资降序
//return arg0.getName().compareTo(arg1.getName()) ; 按照姓名升序
}
});
for(Exmployee e:arrayList)
System.out.println(e.getName()+"'s salary is "+e.getSalary()) ;
}
}
class Exmployee {
public Exmployee(String name, int salary) {
this.name = name ;
this.salary = salary ;
}
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
private int salary;
}
标签:list,集合,对象,排序
![](/images/zang.png)
![](/images/jiucuo.png)
猜你喜欢
Java 8 Stream操作类型及peek示例解析
2021-07-17 20:42:08
C#获取本地IP的四种方式示例详解
2023-04-16 00:52:50
JAVA Future类的使用详解
2023-11-04 22:51:20
![](https://img.aspxhome.com/file/2023/5/88515_0s.jpg)
Android自定义播放器控件VideoView
2023-06-25 03:29:00
基于StreamRead和StreamWriter的使用(实例讲解)
2022-09-11 22:12:36
JDK源码之PriorityQueue解析
2022-05-15 17:17:15
![](https://img.aspxhome.com/file/2023/1/63741_0s.png)
springboot集成shiro详细总结
2022-07-12 14:56:17
![](https://img.aspxhome.com/file/2023/1/105911_0s.png)
Java线程池ThreadPoolExecutor原理及使用实例
2022-04-30 05:53:00
![](https://img.aspxhome.com/file/2023/9/64769_0s.png)
C#异步编程之async/await详解
2022-10-08 02:50:07
![](https://img.aspxhome.com/file/2023/7/85667_0s.png)
Android 13新功能及适配工作详解
2022-04-13 11:05:33
一篇文章弄懂kotlin的扩展方法
2022-06-05 08:06:20
Java中关于字符串的编码方式
2023-01-30 04:59:45
![](https://img.aspxhome.com/file/2023/3/110823_0s.png)
基于C#中XmlWriter写入Xml的深入分析
2021-06-29 10:00:54
Java 图表类库详解
2021-11-09 00:25:11
![](https://img.aspxhome.com/file/2023/0/85540_0s.png)
SpringSecurity添加图形验证码认证实现
2023-07-08 01:37:52
Java对XML文件增删改查操作示例
2021-10-28 08:46:29
Android App中实现可以双击放大和缩小图片功能的实例
2023-04-01 16:41:17
unity通过Mesh网格绘制图形球体
2023-12-12 08:08:21
![](https://img.aspxhome.com/file/2023/3/82233_0s.jpg)
C# 操作符之三元操作符浅析
2022-12-18 16:50:47
WPF中鼠标/键盘/拖拽事件以及用行为封装事件详解
2021-05-24 00:22:38
![](https://img.aspxhome.com/file/2023/2/126052_0s.gif)