/**
     * 设置窗口位于屏幕中间
     * @param shell 要调整位置的窗口对象
     */
    public static void center(Shell shell)
    {
        //获取屏幕高度和宽度
        int screenH = Toolkit.getDefaultToolkit().getScreenSize().height;
        int screenW = Toolkit.getDefaultToolkit().getScreenSize().width;
        //获取对象窗口高度和宽度
        int shellH = shell.getBounds().height;
        int shellW = shell.getBounds().width;
        
        //如果对象窗口高度超出屏幕高度，则强制其与屏幕等高
        if(shellH > screenH)
            shellH = screenH;
        
        //如果对象窗口宽度超出屏幕宽度，则强制其与屏幕等宽
        if(shellW > screenW)
            shellW = screenW;
        
        //定位对象窗口坐标
        shell.setLocation(((screenW - shellW) / 2), ((screenH - shellH) / 2));
    }
    
    /**
     * 设置窗口位于屏幕中间
     * @param display 设备
     * @param shell 要调整位置的窗口对象
     */
    public static void center(Display display, Shell shell)
    {
        Rectangle bounds = display.getPrimaryMonitor().getBounds();
        Rectangle rect = shell.getBounds();
        int x = bounds.x + (bounds.width - rect.width) / 2;
        int y = bounds.y + (bounds.height - rect.height) / 2;
        shell.setLocation(x, y);
    }