1 package com.test;
2
3 import java.util.HashMap;
4 import java.util.Iterator;
5 import java.util.Map;
6 import java.util.Set;
7
8 /**
9 * Created by Donge on 2017/2/6.
10 */
11 public class TestMap {
12 public static void main(String[] args) {
13 Map<Integer, String> map = new HashMap<>();
14 map.put(1, "v1");
15 map.put(2, "v2");
16 map.put(3, "v3");
17 // 方法一 推荐
18 for (Map.Entry e : map.entrySet()) {
19 System.out.println(e.getKey() + " : " + e.getValue());
20 }
21 System.out.println("*************************");
22 // 方法二
23 Set<Integer> keys = map.keySet();
24 for (Integer k : keys){
25 System.out.println(k+" : "+map.get(k));
26 }
27 System.out.println("*************************");
28 // 方法三
29 Iterator<Integer> iterator = map.keySet().iterator();
30 while (iterator.hasNext()){
31 Integer key = iterator.next();
32 System.out.println(key+" : "+map.get(key));
33 }
34 System.out.println("*************************");
35 // 方法四 此方法不能获取key值
36 for (String v : map.values()){
37 System.out.println(v);
38 }
39 }
40 }
