1 //: SpringDetector2.java
2 package cn.skyfffire;
3
4 import java.util.Enumeration;
5 import java.util.Hashtable;
6
7 /**
8 * @user: skyfffire
9 * @data: 2017年3月14日
10 * @time: 下午6:31:13
11 */
12 class Groundhog2 {
13 int ghNumber;
14
15 Groundhog2(int n) {
16 ghNumber = n;
17 }
18
19 // Hashtable的get方法要使用这个方法
20 @Override
21 public int hashCode() {
22 return ghNumber;
23 }
24
25 // HashTable的containsKey要使用
26 @Override
27 public boolean equals(Object o) {
28 return (o instanceof Groundhog2)
29 && (ghNumber == ((Groundhog2)o).ghNumber);
30 }
31 }
32
33 public class SpringDetector2 {
34 public static void main(String[] args) {
35 // 为了方便查看其中的键值对，复写了Hashtable的toString
36 Hashtable<Groundhog2, Prediction> ht =
37 new Hashtable<Groundhog2, Prediction>() {
38 private static final long serialVersionUID = -8222553412985239408L;
39
40 @Override
41 public String toString() {
42 String str = "";
43 Enumeration<Groundhog2> ge = this.keys();
44
45 while (ge.hasMoreElements()) {
46 Groundhog2 gh2 = ge.nextElement();
47
48 str += (gh2 + " = " + this.get(gh2) + "\n");
49 }
50
51 return str;
52 }
53 };
54
55 // 添加十个键值对
56 for (int i = 0; i < 10; i++) {
57 ht.put(new Groundhog2(i), new Prediction());
58 }
59
60 // 查看键值对中的内容
61 System.out.println(ht.toString());
62 System.out.println(
63 "Looking up prediction for groundhog #3:");
64
65 // 复写了hashCode之后可以方便地比较ghNumber相同的键
66 Groundhog2 hg = new Groundhog2(3);
67
68 if (ht.containsKey(hg)) {
69 System.out.println((Prediction)ht.get(hg));
70 }
71 }
72 }
73
74 ///:~
