swt为关闭窗口添加确认事件

shell.addShellListener(new ShellAdapter() {
            public void shellClosed(ShellEvent e) {
                MessageBox messagebox = new MessageBox(shell, SWT.ICON_QUESTION
                        | SWT.YES | SWT.NO);
                messagebox.setText("messageBox范例");
                messagebox.setMessage("您确定要退出吗?") ;
                int message = messagebox.open();
                e.doit = message == SWT.YES;
            }

});