【java编程】Map集合之hashMap两种取出方式练习

import java.util.*;
/*练习.HashMap两种取出方式
  条件：每一个学生都有对应的归属地。
	学生Student，地址String
  	学生属性:姓名，年龄
  注意：姓名和年龄相同的视为同一个学生。
 	保证学生的唯一性*/
class StuHashMapDemo 
{
	public static void main(String[] args) 
	{
		HashMap<Student,String> hm=new HashMap<Student,String>();
		hm.put(new Student("wangcong",25),"beijing");
		hm.put(new Student("wangming",23),"shanghai");
		hm.put(new Student("wangfan",25),"wuhan");
		hm.put(new Student("wangliang",22),"tianjing");
		hm.put(new Student("wangerxiao",26),"nanjing");
		//第一种取出方式keySet
		Set<Student> keySet=hm.keySet();
		Iterator<Student> it=keySet.iterator();
		while(it.hasNext())
		{
			Student stu=it.next();
			String addr=hm.get(stu);
			System.out.println(stu.getName()+":"+stu.getAge()+"........"+addr);
		}
		//第二种取出方式entrySet
		Set<Map.Entry<Student,String>> entrySet=hm.entrySet();
		Iterator<Map.Entry<Student,String>> iter=entrySet.iterator();
		while(iter.hasNext())
		{
			Map.Entry<Student,String> me=iter.next();
			Student stu=me.getKey();
			String addr=me.getValue();
			System.out.println(stu.getName()+":"+stu.getAge()+"........"+addr);
		}
		
		
	}
}
class Student implements Comparable<Student>//实现Comparable方法让Student具备比较性
{
	private String name;
	private int age;
	Student(String name,int age)
	{
		this.name=name;
		this.age=age;
	}
	public String getName()
	{
		return name;
	}
	public int getAge()
	{
		return age;
	}
	//复写hashCode方法为哈希表判断重复元素使用
	public int hashCode()
	{
		return this.name.hashCode()+age*20;
	}
	//复写equals方法
	public boolean equals(Object obj)
	{
		if(!(obj instanceof Student))
			throw new ClassCastException("类型不匹配！");
		Student s=(Student)obj;
		return this.name.equals(s.getName()) && this.age==s.getAge();
	}
	//复写compareTo方法
	public int compareTo(Student s)
	{
		int num=new Integer(this.age).compareTo(new Integer(s.getAge()));
		if(num==0)
			return this.name.compareTo(s.getName());
		return num;
	}
	
}