java中遍历map的三种方式

    public static void main(String[] args) {
        HashMap<String,String> map = new HashMap<>();
        map.put("1","A");
        map.put("2","B");
        map.put("3","C");
        map.put("4","D");
        map.put("5","E");
        map.put("6","F");
        //遍历的方式1
        Set<String> keys = map.keySet();
        for (String key : keys) {
            System.out.println(key+"-->"+map.get(key));
        }
        //遍历的方式2
        Set<Map.Entry<String, String>> entries = map.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            String key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key+"-->"+value);
        }
        //遍历的方式3  jdk8.0以后开始的新技术
        map.forEach((k,v)->{
            System.out.println(k+"-->"+v);
        });
    }