获取Map的key值的几种方式

1. 调用keySet方法：

   @Test
   public void getKeys1(){
       Map<String, Object> map = new HashMap<>();
       ("name","曹操");
       ("sex","男");
       ("age","21");
       ("():"+());
       Iterator<String> iterator = ().iterator();
       while (()){
           ("iterator:"+());
       }
       Set<String> keySet = ();
       // 遍历keySet，并输出key的值
       for(String key : keySet){
           (key+":"+(key).toString());
       }
   }
   

输出：

():[sex, name, age]
iterator:sex
iterator:name
iterator:age
sex:男
name:曹操
age:21

2. entrySet()

   @Test
   public void getKeys2(){
       Map<String, Object> map = new HashMap<>();
       ("name","曹操");
       ("sex","男");
       ("age","21");
       //第二种
       ("():"+());
       Iterator<<String, Object>> iterator = ().iterator();
       while (()){
           ("iterator:"+());
       }
       for (<String, Object> entry : ()){
           ("key:"+()+";value:"+());
       }
   }
   

输出：

():[sex=男, name=曹操, age=21]
iterator:sex=男
iterator:name=曹操
iterator:age=21
key:sex;value:男
key:name;value:曹操
key:age;value:21

参考链接：
/cailijuan/p/