【java编程】Collection类之HashSet存储自定义对象元素

/*SET集合是无序的，判断无序的方法是先比较hashcode值，如果相同
  再比较equals方法*/
import java.util.*;
class hashCodeDemo
{
	public static void main(String[] args) 
	{
		HashSet hs = new HashSet();
		hs.add(new Person("lisi",33));
		hs.add(new Person("lisi",34));
		hs.add(new Person("lisi",35));
		hs.add(new Person("lisi",35));
		hs.add(new Person("lisi",36));
		hs.add(new Person("lisi",36));		
		Iterator it = hs.iterator();
		while(it.hasNext())
		{
			//因为ArrayList里面添加对象时都被强制转换成Object类型
			Person p=(Person)it.next();
			System.out.println(p.getName()+"::"+p.getAge());
		}
	}

}
class Person
{
	private String name;
	private int age;
	Person(String name,int age)
	{
		this.name=name;
		this.age=age;
	}
	public String getName()
	{
		return this.name;
	}
	public int getAge()
	{
		return this.age;
	}
	//复写equals方法
	public boolean equals(Object obj)
	{
		Person p = (Person)obj;
		System.out.println(this.name+"......equals......"+p.getName());
		return this.name.equals(p.getName()) && this.age==p.getAge();
	}
	//复写hashCode方法
	public int hashCode()
	{
		System.out.println(this.name+"......hashCode");
		return name.hashCode()+age*39;
	}

}