【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);
         }

     }

 }