package?com.imooc.Map;


import?java.util.HashMap;
import?java.util.Map;
import?java.util.Map.Entry;
import?java.util.Scanner;
import?java.util.Set;

import?com.imooc.collection.Student;

public?class?MapTest?{
	public?Map<String,Student>students;
	/*
	?*?在構造器中初始化students屬性
	?*/
	public?MapTest(){
		this.students=new?HashMap();
	}
	/*
	?*?添加學生：
	?*?首先檢查是否被占用，如果被占用，輸出提示信息
	?*?如若沒有，將該學生信息輸入到學生的屬性中，并打印出學生信息
	?*/

	public?void?TestPut(){
		int?i=0;
		while(i<3){//此處用while循環更加合適?。。?		System.out.println("請輸入學號：");
		Scanner?input=new?Scanner(System.in);
		String?id=input.next();
		Student?newStudent=students.get(id);
		if(newStudent==null){
		System.out.println("請輸入姓名：");
		
		String?name=input.next();
		//創建學生對象
		Student?a=new?Student(id,name);
		students.put(id,?a);
		System.out.println("成功添加學生"+students.get(id).name);
		i++;
		}else{
			System.out.println("您的id已被占用！");
			continue;
		}??		
		}	
	}
	public?void?testKeySet(){
		//通過keySet方法，返回Map中的所有"鍵"的Set集合
		Set<String>?keySet=students.keySet();
		//遍歷keySet,取得每個key值，再調用get方法取得每個鍵對應的value
		for(String?stuID:keySet){
			Student?st=students.get(stuID);
			System.out.println(st.name);			
		}		
	}
	
	/*
	?*?刪除Map中的映射
	?*/
	public?void?testRemove(){
		System.out.println("請輸入要刪除的id：");
		while(true){
		Scanner?input=new?Scanner(System.in);
		String?id=input.next();
		Student?st=students.get(id);
		if(st==null){
			System.out.println("您輸入的id不存在，請重新輸入：");
			continue;
		}
		students.remove(id);
		System.out.println("已經成功刪除"+st.name);
		break;
		}
	}
	/*
	?*?通過entrySet方法遍歷Map
	?*/
	public?void?testEntrySet(){
		//通過entrySet方法返回所有的鍵值對
		Set<Entry<String,?Student>>?entrySet=students.entrySet();
		for(Entry?es:entrySet){
			System.out.println("key值："+es.getKey());
			System.out.println("Value值："+es.getValue());	
		}
		
	}
	
	

	
	public?static?void?main(String[]?args){
?????????MapTest?mt=new?MapTest();
?????????mt.TestPut();
?????????mt.testKeySet();	
?????????mt.testRemove();
?????????mt.testEntrySet();
	}
}

Student代碼：

package?com.imooc.collection;

import?java.util.HashSet;
import?java.util.Set;

public?class?Student?{
	?public?String?id;
	?public?String?name;?
	?public?Set<Course>?courses;
	?
	?public?Student(String?id,String?name){
		?this.id=id;
		?this.name=name;
		?this.courses=new?HashSet<Course>();
		?
	?}
	

}