jdialog的问题

[viva2002]

请问怎样让弹出的dialog居中显示，且一直居于父窗口的前面？谢谢！！

[geyf]

Rectangle frameRect = frame.getBounds();
Dimension dialogSize = _dialog.getSize();
dialog.setLocation((frameRect.width-dialogSize.width) / 2 +frameRect.x ,
(frameRect.height-dialogSize.height) / 2 +frameRect.y);
dialog.setVisible(true);