Java_基础—集合嵌套之HashMap嵌套HashMap

package com.soar.map;

import java.util.HashMap;

import com.soar.bean.Student;

public class Demo8_HashMapHashMap {
    /*
     * * A:案例演示
     * 集合嵌套之HashMap嵌套HashMap
     * 
     * 需求：
     * 一班键是学生，值是学生的归属地
     * 二班键是学生，值是学生的归属地
     * 
     * 将班级对象添加到双列集合中
     */
    public static void main(String[] args) {
        //定义一班
        HashMap<Student,String> hm1 = new HashMap<>();
        hm1.put(new Student("张三",23),"北京");
        hm1.put(new Student("李四",24),"北京");
        hm1.put(new Student("王五",25),"上海");
        hm1.put(new Student("赵六",26),"广州");

        //定义二班
        HashMap<Student,String> hm2 = new HashMap<>();
        hm2.put(new Student("唐僧",123),"北京");
        hm2.put(new Student("孙悟空",1024),"北京");
        hm2.put(new Student("猪八戒",1025),"上海");
        hm2.put(new Student("沙和尚",269),"广州");

        //定义大集合
        HashMap<HashMap<Student,String>,String> hm = new HashMap<>();
        hm.put(hm1, "一班");
        hm.put(hm2, "二班");

        //遍历双列集合
        for (HashMap<Student,String> h : hm.keySet()) { //hm.keySet()代表的是双列集合中键的集合
            String value = hm.get(h);                   //get(h)根据键对象获取值对象
            //遍历键的双列集合对象
            for (Student key : h.keySet()) {        //h.keySet()获取集合中所有的学生键对象
                String value2 = h.get(key);
                System.out.println(key + "=" + value2 + value);
                /*

Student [name=孙悟空, age=1024]=北京二班
Student [name=猪八戒, age=1025]=上海二班
Student [name=沙和尚, age=269]=广州二班
Student [name=唐僧, age=123]=北京二班
Student [name=张三, age=23]=北京一班
Student [name=李四, age=24]=北京一班
Student [name=王五, age=25]=上海一班
Student [name=赵六, age=26]=广州一班

                */
            }
        }
    }

}