Java排序之集合排序 Java排序之集合排序

集合排序

要么让集合的对象具有比较性也就是让集合中的对象实现Comparable接口
自定义比较器实现Comparator

举例：按人的年龄排序 【Java排序之集合排序】代码如下

UserBean对象

/** * Created by yuandl on 2016-10-10. */ public class UserBean implements Comparable { private String name; private int age; public UserBean(String name, int age) { this.name = name; this.age = age; }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 "UserBean{" + "name='" + name + '\'' + ", age=" + age + '}'; }@Override public int compareTo(UserBean o) { return this.age-o.age; } }

主要代码

import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; /** * Created by yuandl on 2016-10-10. */ public class ListTest { public static void main(String args[]) { List list = new ArrayList<>(); list.add(new UserBean("张三", 56)); list.add(new UserBean("张2", 5)); list.add(new UserBean("张6", 34)); list.add(new UserBean("张5", 6)); list.add(new UserBean("张9", 76)); Collections.sort(list); //让list中的对象具有比较性即UserBean implements Comparable Collections.sort(list, new Comparator() {//自定义比较器 @Override public int compare(UserBean o1, UserBean o2) { return o1.getAge()-o2.getAge(); } }); System.out.println(list); } }