Java NullPointerException在春季重定向

我在使用WebLogic服务器的Spring框架MVC（3.2.8）应用程序中工作 我有这段代码

@RequestMapping(value = {"/accounts/saveaccount.do"}, method = { RequestMethod.POST})
    private String saveAccount  (   @Valid @ModelAttribute("dataAccountCommand") final DataAccountCommand dataAccountCommand, 
                                    Errors errors,
                                    final HttpServletRequest request, 
                                    final Model model) throws Exception {

        if (isBackAction(request)) {

            return request.getContextPath() + "redirect:/welcome/welcome.do";
        }

但我有一个空指针

java.lang.NullPointerException
        at org.springframework.web.servlet.view.UrlBasedViewResolver.loadView(UrlBasedViewResolver.java:438)
        at org.springframework.web.servlet.view.AbstractCachingViewResolver.createView(AbstractCachingViewResolver.java:241)
        at org.springframework.web.servlet.view.UrlBasedViewResolver.createView(UrlBasedViewResolver.java:401)
        at org.springframework.web.servlet.view.AbstractCachingViewResolver.resolveViewName(AbstractCachingViewResolver.java:153)
        at org.springframework.web.servlet.DispatcherServlet.resolveViewName(DispatcherServlet.java:1239)
        at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1188)
        at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:751)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:844)
        at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
        at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
        at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
        at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:341)
        at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:25)
        at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)

---

删除

request.getContextPath（）

，它应该是

返回“重定向：/welcome/welcome.do”

删除请求.getContextPath（），它应该是

返回“重定向：/welcome/welcome.do”

@请转换为答案