ServletContextListener的实现类中怎么获取Spring配置中的bean

ServletContextListener的实现类中如何获取Spring配置中的bean

示例代码如下：

?

public class Test implements ServletContextListener {

? public IMessageService messageService;

? public void setMessageService(IMessageService messageService) {
????? this.messageService = messageService;
? }

? public void contextInitialized(ServletContextEvent sce) {
????? ApplicationContext ac = null;

????? ac = WebApplicationContextUtils.getRequiredWebApplicationContext(sce.getServletContext ());

????? setMessageService ((IMessageService) ac.getBean ("MessageServiceImpl"));
? }

}