java map 遍历

 

1 package com.spring.test_B11_aop1;
 2 
 3 import java.util.HashMap;
 4 import java.util.Iterator;
 5 import java.util.Map;
 6 import java.util.Set;
 7 
 8 public class MapTest {
 9 
10     public static void main(String[] args) {
11         // java中遍历MAP的几种方法
12         // Java代码
13         Map<String, String> map = new HashMap<String, String>();
14         map.put("username", "qq");
15         map.put("passWord", "123");
16         map.put("userID", "1");
17         map.put("email", "[e-mail]");
18         
19         // 第一种用for循环
20         // Java代码
21         for (Map.Entry<String, String> entry : map.entrySet()) {
22             System.out.println(entry.getKey() + "--->" + entry.getValue());
23         }
24 
25         // 第二种用迭代
26         // Java代码
27         Set<?> set = map.entrySet();
28         Iterator<?> i = set.iterator();
29         while (i.hasNext()) {
30             @SuppressWarnings("unchecked")
31             Map.Entry<String, String> entry1 = (Map.Entry<String, String>) i.next();
32             System.out.println(entry1.getKey() + "==" + entry1.getValue());
33         }
34         
35 
36         // 用keySet()迭代
37         // Java代码
38         Iterator<String> it = map.keySet().iterator();
39         while (it.hasNext()) {
40             String key;
41             String value;
42             key = it.next().toString();
43             value = map.get(key);
44             System.out.println(key + "--" + value);
45         }
46 
47         // 用entrySet()迭代
48         // Java代码
49         Iterator<?> it2 = map.entrySet().iterator();
50         System.out.println(map.entrySet().size());
51         String key;
52         String value;
53         while (it2.hasNext()) {
54             @SuppressWarnings("rawtypes")
55             Map.Entry entry = (Map.Entry) it2.next();
56             key = entry.getKey().toString();
57             value = entry.getValue().toString();
58             System.out.println(key + "====" + value);
59         }
60     }
61 }