Servlet 调用 Spring 容器的 service

自定义（继承自 javax.servlet.http.HttpServlet）的 Servlet 如何像 Struts1/2 中那样调用 Spring 容器的 service 呢？
如同 Struts1/2 的配置一样，Spring 在 web.xml 中的配置及其 application*.xml 配置不变：
web.xml 中：

<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/applicationContext*.xml</param-value>
</context-param>

	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>/WEB-INF/applicationContext*.xml</param-value>
	</context-param>

applicationContext-service.xml 中：

<beanid="operationService"
class="com.defonds.cds.service.operation.impl.OperationServiceImpl"scope="singleton">
</bean>

	<bean id="operationService"
		class="com.defonds.cds.service.operation.impl.OperationServiceImpl" scope="singleton">
	</bean>

如同一般的 Servlet 的配置一样，Servlet 在 web.xml 中的配置不变：

<servlet>
<servlet-name>downloadServlet</servlet-name>
<servlet-class>com.defonds.cds.common.ArcSyncDownloadServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>downloadServlet</servlet-name>
<url-pattern>/file</url-pattern>
</servlet-mapping>

	<servlet>
		<servlet-name>downloadServlet</servlet-name>
		<servlet-class>com.defonds.cds.common.ArcSyncDownloadServlet</servlet-class>
	</servlet>	
	<servlet-mapping>
		<servlet-name>downloadServlet</servlet-name>
		<url-pattern>/file</url-pattern>
	</servlet-mapping>	

如同一般的 Struts1/2 的 action 一样注入 service：

privateOperationServiceoperationService=null;
publicOperationServicegetOperationService(){
returnoperationService;
}

publicvoidsetOperationService(OperationServiceoperationService){
this.operationService=operationService;
}

	private OperationService operationService = null;
	public OperationService getOperationService() {
		return operationService;
	}

	public void setOperationService(OperationService operationService) {
		this.operationService = operationService;
	}

在 Servlet 中如同一般的Struts1/2 的 action 一样调用 service：

FileInfofileInfo=this.getOperationService().getFileByFidAndSecret(Long.parseLong(fileId),secret);

	FileInfo fileInfo = this.getOperationService().getFileByFidAndSecret(Long.parseLong(fileId), secret);

唯一需要修改的是 Servlet 的 init 方法：

publicvoidinit(ServletConfigconfig)throwsServletException{
super.init(config);
ServletContextservletContext=this.getServletContext();
WebApplicationContextwac=null;
wac=WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
this.setOperationService((OperationService)wac.getBean("operationService"));//Spring配置中的beanid
}