testEntrySet應該這樣寫

你少了一行代碼foreach循環

	public?void?testEntrySet()	
	{		
	Set<Entry<String,Student>>entrySet=students.entrySet();		
	for?(Entry<String,?Student>?entry?:?entrySet)?		
	{			
	System.out.println("取得鍵值"+entry.getKey());			
	System.out.println("對應的值為："+entry.getValue().id);		
	}	
	}