常常遇到数组排序的问题.比如我有一个Person类,它的实例对象存储在ArrayList数组中,现在要把ArrayList数组中的Person对象按照年龄排序. 其实这种情况经常遇到. 下面给出源代码: 1:Person.java文件:------------------------------- public class Person{ String name; int age; public Person(String name,int age){ this.name = name; this.age = age; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } } 2:Mycomparator.java------------------------------- //实现Comparator接口,也就是定义排序规则,你几乎可以定义任何规则 package com.infoearth; import java.util.*; public class Mycomparator implements Comparator{
public int compare(Object o1,Object o2) { Person p1=(Person)o1; Person p2=(Person)o2; if(p1.age<p2.age) return 1; else return 0; } } 3:ListSort.java------------------------------------ package com.infoearth; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; public class ListSort { public static void main(String[] args){ ArrayList list = new ArrayList(); list.add(new Person("lcl",28)); list.add(new Person("fx",23)); list.add(new Person("wqx",29)); Comparator comp = new Mycomparator(); Collections.sort(list,comp); for(int i = 0;i<list.size();i++){ Person p = (Person)list.get(i); System.out.println(p.getName()); } } } |