JavaSE-Map的三种循环

 1 public class Foreach {
 2     public static void main(String[] args) {
 3         Map<String, String> map = new HashMap<String, String>();
 4         
 5         //循环map的key的Set集合-->不推荐
 6         for (String key : map.keySet()) {
 7             //key
 8             String val = map.get(key);
 9         }
10         
11         //循环map的entry的Set集合-->最推荐的方式
12         for (Entry<String, String> entry : map.entrySet()) {
13             String key = entry.getKey();
14             String val = entry.getValue();
15         }
16         
17         //循环map的值-->只取值的推荐方式
18         for (String val : map.values()) {
19             String valOld = val;
20         }
21     }
22 }