Arraylist判断重复用equals方法,HashSet用HashCode和equals方法。

如果姓名和年龄相同则重复,不打印

import java.util.*;
class h 
{
	public static void main(String[] args) 
	{
		HashSet sh = new HashSet();
		sh.add(new person("a1",11));
		sh.add(new person("a2",12));
		sh.add(new person("a2",12));
		sh.add(new person("a3",13));

		for(Iterator it = sh.iterator();it.hasNext();)//循环读元素
		{
			person p  = (person)it.next();
			sop(p.getName()+","+p.getAge());
		}
	}
	public static void sop(Object obj)
	{
		System.out.println(obj);
	}
}
class person
{
	private String name;
	private int age;
	person(String name,int age)
	{
		this.name = name;
		this.age = age;
	}
	public int hashCode()//增加HASH值
	{
		return name.hashCode()+age;
	}
	public boolean equals(Object obj)//判断是否重复,equals方法
	{
		if(!(obj instanceof person))
			return false;
		person p = (person)obj;
		return this.name.equals(p.name)&&this.age==p.age;
	}
	public String getName()
	{
		return name;
	}
	public int getAge()
	{
		return age;
	}
}


posted on 2015-10-22 15:10  超宇  阅读(145)  评论(0编辑  收藏  举报