Java基础知识强化之集合框架笔记60：Map集合之TreeMap（TreeMap<Student，String>）的案例

1. TreeMap（TreeMap<Student，String>）的案例

2. 案例代码：

（1）Student.java：

 1 package cn.itcast_04;
 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 }

（2）测试类TreeMapDemo2，如下：

 1 package cn.itcast_04;
 2
 3 import java.util.Comparator;
 4 import java.util.Set;
 5 import java.util.TreeMap;
 6
 7 /*
 8  * TreeMap<Student,String>
 9  * 键:Student
10  * 值：String
11  */
12 public class TreeMapDemo2 {
13     public static void main(String[] args) {
14         // 创建集合对象
15         TreeMap<Student, String> tm = new TreeMap<Student, String>(
16                 new Comparator<Student>() {
17                     @Override
18                     public int compare(Student s1, Student s2) {
19                         // 主要条件
20                         int num = s1.getAge() - s2.getAge();
21                         // 次要条件
22                         int num2 = num == 0 ? s1.getName().compareTo(
23                                 s2.getName()) : num;
24                         return num2;
25                     }
26                 });
27
28         // 创建学生对象
29         Student s1 = new Student("潘安", 30);
30         Student s2 = new Student("柳下惠", 35);
31         Student s3 = new Student("唐伯虎", 33);
32         Student s4 = new Student("燕青", 32);
33         Student s5 = new Student("唐伯虎", 33);
34
35         // 存储元素
36         tm.put(s1, "宋朝");
37         tm.put(s2, "元朝");
38         tm.put(s3, "明朝");
39         tm.put(s4, "清朝");
40         tm.put(s5, "汉朝");
41
42         // 遍历
43         Set<Student> set = tm.keySet();
44         for (Student key : set) {
45             String value = tm.get(key);
46             System.out.println(key.getName() + "---" + key.getAge() + "---"
47                     + value);
48         }
49     }
50 }

运行效果，如下：