1 public static void main(String[] args) {
2
3
4 Map<String, String> map = new HashMap<String, String>();
5 map.put("1", "value1");
6 map.put("2", "value2");
7 map.put("3", "value3");
8
9 //第一种：普遍使用，二次取值
10 System.out.println("通过Map.keySet遍历key和value：");
11 for (String key : map.keySet()) {
12 System.out.println("key= "+ key + " and value= " + map.get(key));
13 }
14
15 //第二种
16 System.out.println("通过Map.entrySet使用iterator遍历key和value：");
17 Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
18 while (it.hasNext()) {
19 Map.Entry<String, String> entry = it.next();
20 System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
21 }
22
23 //第三种：推荐，尤其是容量大时
24 System.out.println("通过Map.entrySet遍历key和value");
25 for (Map.Entry<String, String> entry : map.entrySet()) {
26 System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
27 }
28
29 //第四种
30 System.out.println("通过Map.values()遍历所有的value，但不能遍历key");
31 for (String v : map.values()) {
32 System.out.println("value= " + v);
33 }
34 }
