Map集合的三种遍历方法

63 阅读 0 评论 42 点赞

我是靠谱客的博主高兴夏天，最近开发中收集的这篇文章主要介绍Map集合的三种遍历方法，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

package exercise;

import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class MapTest {
   public static void main(String[] args) {
       Map map = new HashMap();

       Student s1 = new Student(1,"zhangsan",88);
       Student s2 = new Student(2,"lisi",87);
       Student s3 = new Student(3,"wangwu",99);
       Student s4 = new Student(4,"zhaoliu",77);

       map.put(s1, 1);
       map.put(s2, 1);
       map.put(s3, 1);
       map.put(s4, 1);

       System.out.println("map中元素个数是："+map.size());
       System.out.println("key为10的value值："+map.get(10));
       System.out.println(map.containsKey(true));
       map.remove("hello");
       map.remove(true,false);
       System.out.println("map中元素个数："+map.size());

       //遍历map(1)
       Set set = map.keySet();
       Iterator site = set.iterator();
       while (site.hasNext()) {
           Object key = site.next();
           Object value = map.get(key);
           System.out.println(key+" = "+value);
       }
       System.out.println("----------------------------");
       //遍历map(2)
       Set kvs =map.entrySet();
       Iterator kvite = kvs.iterator();
       while (kvite.hasNext()) {
           Map.Entry kv = (Map.Entry) kvite.next();
           Object key = kv.getKey();
           Object value = kv.getValue();
           System.out.println(key+" = "+value);
       }
       System.out.println("--------------------------");
        //遍历map(3)
       Collection values = map.values();
       for(Object value:values){
           System.out.println("value:"+value);
       }
   }

}