Map集合的两种迭代方法

直接上代码
 1     @Test
 2     public void test3(){
 3         
 4         Map<Integer, String> m = new HashMap<Integer, String>();
 5         m.put(1, "one");
 6         m.put(2, "two");
 7         m.put(3, "three");
 8         Set<Map.Entry<Integer, String>> set = m.entrySet();
 9         Iterator<Map.Entry<Integer, String>> i = set.iterator();
10         while(i.hasNext()){
11             Entry<Integer, String> entry = i.next();
12             int key = entry.getKey();
13             String value = entry.getValue();
14             System.out.println(key+"="+value);
15             
16         }
17         
18     }
19     
20     @Test
21     public void test4(){
22         
23         Map<Integer, String> m = new HashMap<Integer, String>();
24         m.put(1, "one");
25         m.put(2, "two");
26         m.put(3, "three");
27         Set<Integer> set = m.keySet();
28         Iterator<Integer> i = set.iterator();
29         while(i.hasNext()){
30             int key = i.next();
31             String value = m.get(key);
32             System.out.println(key+"="+value);
33         }
34     }