JDialog居中

int windowWidth = this.getWidth(); //获得窗口宽

int windowHeight = this.getHeight(); //获得窗口高

Toolkit kit = Toolkit.getDefaultToolkit(); //定义工具包

Dimension screenSize = kit.getScreenSize(); //获取屏幕的尺寸

int screenWidth = screenSize.width; //获取屏幕的宽

int screenHeight = screenSize.height; //获取屏幕的高

this.setLocation(screenWidth / 2 - windowWidth / 2, screenHeight / 2 - windowHeight / 2);//设置窗口居中显示

JDialog居中

原文：http://www.cnblogs.com/softidea/p/4530918.html