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

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

2. 案例代码：

（1）Student.java：

 package cn.itcast_04;

 public class Student {
     private String name;
     private int age;

     public Student() {
         super();
     }

     public Student(String name, int age) {
         super();
         this.name = name;
         this.age = age;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }
 }

（2）测试类TreeMapDemo2，如下：

 package cn.itcast_04;

 import java.util.Comparator;
 import java.util.Set;
 import java.util.TreeMap;

 /*
  * TreeMap<Student,String>
  * 键:Student
  * 值：String
  */
 public class TreeMapDemo2 {
     public static void main(String[] args) {
         // 创建集合对象
         TreeMap<Student, String> tm = new TreeMap<Student, String>(
                 new Comparator<Student>() {
                     @Override
                     public int compare(Student s1, Student s2) {
                         // 主要条件
                         int num = s1.getAge() - s2.getAge();
                         // 次要条件
                         int num2 = num == 0 ? s1.getName().compareTo(
                                 s2.getName()) : num;
                         return num2;
                     }
                 });

         // 创建学生对象
         Student s1 = new Student("潘安", 30);
         Student s2 = new Student("柳下惠", 35);
         Student s3 = new Student("唐伯虎", 33);
         Student s4 = new Student("燕青", 32);
         Student s5 = new Student("唐伯虎", 33);

         // 存储元素
         tm.put(s1, "宋朝");
         tm.put(s2, "元朝");
         tm.put(s3, "明朝");
         tm.put(s4, "清朝");
         tm.put(s5, "汉朝");

         // 遍历
         Set<Student> set = tm.keySet();
         for (Student key : set) {
             String value = tm.get(key);
             System.out.println(key.getName() + "---" + key.getAge() + "---"
                     + value);
         }
     }
 }

运行效果，如下：