Java_基础—集合嵌套之HashMap嵌套HashMap

女爷i 2022-06-12 07:23 264阅读 0赞

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
    
                    */
                }
            }
        }
    
    }