jf.setUndecorated(true); // 去掉視窗的裝飾
        jf.getRootPane().setWindowDecorationStyle(JRootPane.NONE);

        jf.addWindowStateListener(new WindowStateListener() {

            @Override
            public void windowStateChanged(WindowEvent e) {
                if(e.getOldState()==JFrame.ICONIFIED&&!jf.isActive
 
()){
                    jf.setExtendedState(Frame.MAXIMIZED_BOTH);//最大化
                    jf.toFront();
                }
            }
        });