七种遍历HashMap的方法

最新推荐文章于 2024-05-09 09:28:14 发布

weixin_44287819

最新推荐文章于 2024-05-09 09:28:14 发布

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文章标签： java servlet 开发语言

本文链接：https://blog.youkuaiyun.com/weixin_44287819/article/details/126261954

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//7种遍历hashMap的方法
public class HashMapCurrent {
    public static void main(String[] args) {
        HashMap<Integer,String> hashMap = new HashMap<>();
        hashMap.put(1,"xiaoming");
        hashMap.put(2,"xiaobai");
        hashMap.put(3,"xiaohong");
        //迭代器遍历  entrySet
        final Iterator<Map.Entry<Integer, String>> iterator = hashMap.entrySet().iterator();
        while (iterator.hasNext()){
            final Map.Entry<Integer, String> next = iterator.next();
            System.out.println(next.getKey());
            System.out.println(next.getValue());
        }
        // 迭代器遍历  keySet
        final Iterator<Integer> iterator1 =hashMap.keySet().iterator();
        while (iterator1.hasNext()){
            final Integer next = iterator1.next();
            System.out.println(next);
            System.out.println(hashMap.get(next));
        }
        //for循环便利 entrySet
        for(Map.Entry<Integer,String> entry:hashMap.entrySet()){
            System.out.println(entry.getKey());
            System.out.println(entry.getValue());
        }
        //for循环便利keySet
        for(Integer key:hashMap.keySet()){
            System.out.print(key);
            System.out.print(hashMap.get(key));
        }
        //lambda表达式遍历
        hashMap.forEach((key,value)->{
            System.out.println(key);
            System.out.println(value);
        });
        //Stream流遍历  单线程
        hashMap.entrySet().stream().forEach((entry)->{
            System.out.println(entry.getValue());
            System.out.println(entry.getKey());
        });
        //Stream流遍历  多线程
        hashMap.entrySet().parallelStream().forEach((entry)->{
            System.out.println(entry.getKey());
            System.out.println(entry.getValue());
        });
    }
}