1
/**
2 * MapTest.java
3 *
4 * Provider: CoderDream's Studio
5 *
6 * History
7 * Date(DD/MM/YYYY) Author Description
8 * ----------------------
9 * Oct 31, 2007 CoderDream Created
10 */
11 package com.coderdream;
12
13 import java.util.HashMap;
14 import java.util.Iterator;
15 import java.util.Map;
16 import java.util.TreeMap;
17
18 /**
19 * @author CoderDream
20 */
21 public class MapTest {
22
23 /**
24 * <pre>
25 * 使用HashMap使用1：
26 * 用迭代器得到map.entrySet(),
27 * 然后通过迭代得到Map.Entry对象，最后打印。
28 * 打印结果未排序
29 * </pre>
30 *
31 */
32 public void f1() {
33 Map map = new HashMap();
34 map.put("1", "Level 1");
35 map.put("2", "Level 2");
36 map.put("3", "Level 3");
37 map.put("4", "Level 4");
38 map.put("F", "Level F");
39 map.put("Q", "Level Q");
40 Iterator it = map.entrySet().iterator();
41 while (it.hasNext()) {
42 Map.Entry e = (Map.Entry) it.next();
43 System.out.println("Key: " + e.getKey() + "; Value: "
44 + e.getValue());
45 }
46 }
47
48 /**
49 * <pre>
50 * 使用泛型模式说明Map中存储的对象类型
51 * </pre>
52 */
53 public void f2() {
54 Map<String, String> map = new HashMap<String, String>();
55 map.put("1", "Mon.");
56 map.put("1", "Monday");
57 map.put("one", "Monday");
58 Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
59
60 while (it.hasNext()) {
61 Map.Entry entry = it.next();
62 System.out.println(entry.getKey() + ":" + entry.getValue());
63 }
64 }
65
66 /**
67 * <pre>
68 * 通过集合Set来得到HashMap中的对象
69 * </pre>
70 *
71 */
72 public void f3() {
73 Map map = new HashMap();
74 map.put("1", "Mon.");
75 map.put("1", "Monday");
76 map.put("one", "Monday");
77 Iterator it = map.keySet().iterator();
78 String tmpKey = null;
79 while (it.hasNext()) {
80 tmpKey = (String) it.next();
81 System.out.println("Key: " + tmpKey
82 + "; Value: " + map.get(tmpKey));
83 }
84 }
85
86 /**
87 * <pre>
88 * 使用TreeMap代替HashMap，取得结果是排序后的结果
89 * </pre>
90 */
91 public void f4() {
92 Map map = new TreeMap();
93 map.put("1", "Level 1");
94 map.put("2", "Level 2");
95 map.put("3", "Level 3");
96 map.put("4", "Level 4");
97 map.put("F", "Level F");
98 map.put("Q", "Level Q");
99 Iterator it = map.entrySet().iterator();
100 while (it.hasNext()) {
101 Map.Entry e = (Map.Entry) it.next();
102 System.out.println("Key: " + e.getKey()
103 + "; Value: " + e.getValue());
104 }
105 }
106
107 /**
108 * @param args
109 */
110 public static void main(String[] args) {
111
112 MapTest mt = new MapTest();
113 System.out.println("----------f1()----------");
114 mt.f1();
115 System.out.println("----------f2()----------");
116 mt.f2();
117 System.out.println("----------f3()----------");
118 mt.f3();
119 System.out.println("----------f4()----------");
120 mt.f4();
121 }
122 }
输出结果：
----------f1()----------
Key: 3; Value: Level 3
Key: 2; Value: Level 2
Key: F; Value: Level F
Key: 1; Value: Level 1
Key: Q; Value: Level Q
Key: 4; Value: Level 4
----------f2()----------
1:Monday
one:Monday
----------f3()----------
Key: 1; Value: Monday
Key: one; Value: Monday
----------f4()----------
Key: 1; Value: Level 1
Key: 2; Value: Level 2
Key: 3; Value: Level 3
Key: 4; Value: Level 4
Key: F; Value: Level F
Key: Q; Value: Level Q