java map扩展知识

小鱼儿 2022-05-19 03:40 122阅读 0赞

/*
    map扩展知识。
    
    map集合被使用是因为具备映射关系。
    
    "yureban"   Student("01" "zhangsan");
    
    "yureban" Student("02" "lisi");
    
    "jiuyeban" "01" "wangwu";
    "jiuyeban" "02" "zhaoliu";
    
    一个学校有多个教室。每一个教室都有名称。
    
    
    */
    
    import java.util.*;
    
    class Student
    {
    	private String id;
    	private String name;
    	Student(String id,String name)
    	{
    		this.id = id;
    		this.name = name;
    	}
    	public String toString()
    	{
    		return id+":::"+name;
    	}
    }
    
    class MapTest7 
    {
    	public static void main(String[] args) 
    	{
    		demo2();
    	}
    
    	public static void demo2()
    	{
    		HashMap<String, List<Student>> czbk = new HashMap<String, List<Student>>();
    		List<Student> yure = new ArrayList<Student>();
    		List<Student> jiuye = new ArrayList<Student>();
    
    		czbk.put("yureban", yure);
    		czbk.put("jiuyeban", jiuye);
    
    		yure.add(new Student("01","zhagnsa"));
    		yure.add(new Student("04","wangwu"));
    		jiuye.add(new Student("01","zhouqi"));
    		jiuye.add(new Student("02","zhaoli"));
    
    		for(Iterator<String> it = czbk.keySet().iterator(); it.hasNext(); )
    		{
    			String roomName = it.next();
    			List<Student> room = czbk.get(roomName);
    			System.out.println(roomName);
    			getInfos(room);
    		}	
    	}
    
    	public static void getInfos(List<Student> list)
    	{
    		for(Iterator<Student> it = list.iterator(); it.hasNext(); )
    		{
    			Student stu = it.next();
    			System.out.println(stu);
    		}
    	}
    
    	public static void demo()
    	{
    		HashMap<String, HashMap<String, String>> czbk = new HashMap<String, HashMap<String, String>>();
    
    		HashMap<String, String> yure = new HashMap<String, String>();
    
    		HashMap<String, String> jiuye = new HashMap<String, String>();
    
    		czbk.put("yureban", yure);
    		czbk.put("jiuyeban", jiuye);
    
    		yure.put("01","zhagnsan");
    		yure.put("02","lisi");
    
    		jiuye.put("01","zhaoliu");
    		jiuye.put("02","wangwu");
    		
    		for(Iterator<String> it = czbk.keySet().iterator(); it.hasNext(); )
    		{
    			String roomName = it.next();
    			HashMap<String, String> room = czbk.get(roomName);
    			System.out.println(roomName);
    			getStudentInfo(room);
    
    		}
    		//getStudentInfo(jiuye);
    
    	}
    
    	public static void getStudentInfo(HashMap<String, String> roomMap) 
    	{
    		for(Iterator<String> it = roomMap.keySet().iterator(); it.hasNext(); )
    		{
    			String id = it.next();
    			String name = roomMap.get(id);
    			System.out.println(id+":"+name);
    		}
    	}
    }