基础视频Day16练习3 - 黑马程序员技术交流社区

package fuxi1;
import java.util.HashMap;
import java.util.Iterator;
/**
* Map集合扩展知识：
* Map集合中可以嵌套Map。
*@author XiaLei
*/
public class Day16Test7 {
public static void main(String[] args) {
HashMap<String,HashMap<Integer,String>> school = new HashMap<String,HashMap<Integer,String>>();
HashMap<Integer,String> room_1 = new HashMap<Integer,String>();
HashMap<Integer,String> room_2 = new HashMap<Integer,String>();//学校里面有两个班级，每个班级里面有学生。
school.put("room_1", room_1);
school.put("room_2", room_2);
room_1.put(01, "zhansan");
room_1.put(02, "lisi");
room_2.put(01, "wangwu");
room_2.put(02, "zhaoliu");
Iterator<String> it = school.keySet().iterator();//遍历学校集合的键
while(it.hasNext()){
String roomName = it.next();//获得班级的名字
HashMap<Integer,String> room = school.get(roomName);//通过班级的名字获得班级位置
System.out.println(roomName);
getStudent(room);//通过班级位置获得每个学生的信息
}
}
private static void getStudent(HashMap<Integer, String> room) {
//获得学生信息方法
Iterator<Integer> it = room.keySet().iterator();
while(it.hasNext()){
Integer num = it.next();
String name = room.get(num);
System.out.println(num+":"+name);
}
}
}

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