JAVA窗口居中

		Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();    //屏幕的大小
		Dimension frameSize = this.getSize();                                   //此窗口的大小
		
		if (frameSize.height > screenSize.height){
			frameSize.height = screenSize.height;
		}
		if (frameSize.width > screenSize.width){
			frameSize.width = screenSize.width;
		}
		this.setLocation((screenSize.width - frameSize.width) / 2  ,(screenSize.height - frameSize.height ) / 2);
		setVisible(true);