Java_單例模式

1. 懶漢式單例模式：在真正用到的時候纔去創建這個單例對象

class Single {
	private static Single instance = null;
	private Single(){	//將構造方法私有化，防止外部創建類實例		
	}
	synchronized public static Single getInstance(){
		if (instance == null)
			instance = new Single();
		return instance;
	}
}

2. 餓漢式單例模式：不管你用得上用不上，一開始就創建這個單利對象

class Single {
	private static Single instance = new Single();
	private Single(){	//將構造方法私有化，防止外部創建類實例		
	}
	synchronized public static Single getInstance(){
		return instance;
	}
}