javax.servlet.http.HttpServletRequest.getServletContext()Ljavax/servlet/ServletContext

开发环境是tomcat7,放到服务器上的tomcat6上面报错

严重: Servlet.service() for servlet springDispatcherServlet threw exception
java.lang.NoSuchMethodError: javax.servlet.http.HttpServletRequest.getServletContext()Ljavax/servlet/ServletContext;
	at com.smxy.study.controller.ZhangFileController.download(ZhangFileController.java:71)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:214)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:748)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:931)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:822)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:807)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

在下载功能的地方出错，在获取文件类型时使用request.getServletContext()

        // 设置文件MIME类型  
        response.setContentType(request.getServletContext().getMimeType(  
                        filename));

ServletRequest的getServletContext方法是Servlet3.0添加的，本地的版本比较高，支持request.getServletContext()这种写法，而线上是Tomcat6.0，只支持到Servlet2.5，需要先用request拿到HttpSession或者通过Servlet自身拿到ServletConfig之后再获取ServletContext，即修改后如下:

        // 设置文件MIME类型  
        response.setContentType(request.getSession().getServletContext().getMimeType(  
                filename));