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