java Map遍历，entitySet方法

public class TestMap {

    public static void main(String[] args) {
        Map<String, String> map = new HashMap<String, String>();
        map.put("1","a");
        map.put("2","s");
        map.put("3","d");
        map.put("4","f");

        System.out.println("取出所有key----------");
        for (String key :map.keySet()){
            System.out.println(key +"---" + map.get(key));
        }

        System.out.println("取出所有value----------");
        for (String value : map.values()) {
            System.out.println("值：" + value);
        }

        System.out.println("取出所有key和value----------");
//        取出对应的 key，value 键值对,容量大时推荐使用
        for (Map.Entry<String,String> entry : map.entrySet()){
            System.out.println("key:" + entry.getKey());
            System.out.println("value:" + entry.getValue());
        }
    }

}