【Java学习笔记】Map借口的子接口----HashMap

存储在HashMap集合中的元素，必须覆盖hashCode和equals方法（与HashSet类似）

 

 

import java.util.HashMap;
import java.util.Iterator;

import cn.itcast.p2.bean.Student;

public class HashMapDemo {

    public static void main(String[] args) {
        /*
         * 将学生对象和学生的归属地通过键与值存储到map集合中
         */
        HashMap<Student,String> hm = new HashMap<Student,String>();
        
        hm.put(new Student("lisi",38), "北京");
        hm.put(new Student("zhaoliu",24), "上海");
        hm.put(new Student("xiaoqiang",31), "沈阳");
        hm.put(new Student("wangcai",38), "大连");
        hm.put(new Student("zhaoliu",24), "铁岭");
        
        Iterator<Student> it = hm.keySet().iterator();
        while (it.hasNext())
        {
            Student key = it.next();
            String value = hm.get(key);
            System.out.println(key.getName()+":"+key.getAge()+"--"+value);
        }

    }

}