本篇文章为大家展示了List集合中的对象如何实现按属性大小排序，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
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 ><span >用collection.sort（）方法对list集合排序</span><br /></p><p ><span ><span ></span></span></p><p >第一种是list中的对象实现Comparable接口，如下：<span > </span></p><pre class="java" >/**
* 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;
}上述内容就是List集合中的对象如何实现按属性大小排序，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注亿速云行业资讯频道。
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