Java基础知识强化之集合框架笔记57：Map集合之HashMap集合（HashMap<Student，String>）的案例

 1 package cn.itcast_02;
 2 
 3 public class Student {
 4     private String name;
 5     private int age;
 6 
 7     public Student() {
 8         super();
 9     }
10 
11     public Student(String name, int age) {
12         super();
13         this.name = name;
14         this.age = age;
15     }
16 
17     public String getName() {
18         return name;
19     }
20 
21     public void setName(String name) {
22         this.name = name;
23     }
24 
25     public int getAge() {
26         return age;
27     }
28 
29     public void setAge(int age) {
30         this.age = age;
31     }
32 
33     @Override
34     public int hashCode() {
35         final int prime = 31;
36         int result = 1;
37         result = prime * result + age;
38         result = prime * result + ((name == null) ? 0 : name.hashCode());
39         return result;
40     }
41 
42     @Override
43     public boolean equals(Object obj) {
44         if (this == obj)
45             return true;
46         if (obj == null)
47             return false;
48         if (getClass() != obj.getClass())
49             return false;
50         Student other = (Student) obj;
51         if (age != other.age)
52             return false;
53         if (name == null) {
54             if (other.name != null)
55                 return false;
56         } else if (!name.equals(other.name))
57             return false;
58         return true;
59     }
60 
61 }

 1 package cn.itcast_02;
 2 
 3 import java.util.HashMap;
 4 import java.util.Set;
 5 
 6 /*
 7  * HashMap<Student,String>
 8  * 键：Student
 9  *         要求：如果两个对象的成员变量值都相同，则为同一个对象。
10  * 值：String
11  */
12 public class HashMapDemo4 {
13     public static void main(String[] args) {
14         // 创建集合对象
15         HashMap<Student, String> hm = new HashMap<Student, String>();
16 
17         // 创建学生对象
18         Student s1 = new Student("貂蝉", 27);
19         Student s2 = new Student("王昭君", 30);
20         Student s3 = new Student("西施", 33);
21         Student s4 = new Student("杨玉环", 35);
22         Student s5 = new Student("貂蝉", 27);
23 
24         // 添加元素
25         hm.put(s1, "8888");
26         hm.put(s2, "6666");
27         hm.put(s3, "5555");
28         hm.put(s4, "7777");
29         hm.put(s5, "9999");
30 
31         // 遍历
32         Set<Student> set = hm.keySet();
33         for (Student key : set) {
34             String value = hm.get(key);
35             System.out.println(key.getName() + "---" + key.getAge() + "---"
36                     + value);
37         }
38     }
39 }