Spring 4 多部分“NullPointerException”问题

Question

我正在尝试使用分段上传文件。

使用 Spring 4.2.5 和 Google 应用引擎 1.9.34

jsp代码：

<form method="post" action="/fileUpload.htm" id="uploadForm"
                    enctype="multipart/form-data">
 <input id="uploadObj" type="file" class="filestyle"  data-buttonName="btn-primary" data-badge="false" data-input="false" data-buttonBefore="true"  data-buttonText="Choose File" multiple name="files" accept=".doc,.docx,.xls,.xlsx,.pdf,.ppt,.pptx">
</form>

控制器代码：

@RequestMapping(value="/fileUpload.htm",method=RequestMethod.POST)
        public String fileUpload(HttpServletRequest request,HttpServletResponse response,HttpSession session,@RequestParam("files") MultipartFile file) throws IOException{

      if(!file.isEmpty()){
              ****
       }
}

多部分 bean 配置：

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    </bean>

错误日志：

Uncaught exception from servlet
    java.lang.NullPointerException
        at java.io.File.<init>(File.java:312)
        at org.apache.commons.fileupload.disk.DiskFileItem.getTempFile(DiskFileItem.java:582)
        at org.apache.commons.fileupload.disk.DiskFileItem.getOutputStream(DiskFileItem.java:528)
        at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:347)
        at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:115)
        at org.springframework.web.multipart.commons.CommonsMultipartResolver.parseRequest(CommonsMultipartResolver.java:158)
        at org.springframework.web.multipart.commons.CommonsMultipartResolver.resolveMultipart(CommonsMultipartResolver.java:142)
        at org.springframework.web.servlet.DispatcherServlet.checkMultipart(DispatcherServlet.java:1089)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:928)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:870)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:844)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:316)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:122)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:169)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:48)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at com.security.GaeAuthenticationFilter.doFilter(GaeAuthenticationFilter.java:90)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176)
        at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
        at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:125)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:37)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.apphosting.utils.servlet.JdbcMySqlConnectionCleanupFilter.doFilter(JdbcMySqlConnectionCleanupFilter.java:60)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:50)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
        at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
        at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
        at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
        at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
        at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:260)
        at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
        at org.mortbay.jetty.Server.handle(Server.java:326)
        at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
        at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
        at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:78)
        at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
        at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:148)
        at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:468)
        at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:437)
        at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:444)
        at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:256)
        at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:308)
        at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:300)
        at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:441)
        at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:235)
        at java.lang.Thread.run(Thread.java:745)

我做错了什么？

因为如果我使用下面的代码一切正常：

final ServletFileUpload servletFileUpload=new ServletFileUpload();
 FileItemIterator fileItemIterator=servletFileUpload.getItemIterator(httpServletRequest);
 while(fileItemIterator.hasNext()){
    ****
}

Answer 1

我也有同样的问题。最后我通过设置系统的属性java.io.tmpdir解决了这个问题。

在 appengine-web.xml 中，添加：

<system-properties>
  <property name="java.io.tmpdir" value="/"/>
  ...
</system-properties>

希望有帮助

Answer 2

我在使用 FileItemsIterator 时遇到了同样的异常... List fileItemsList = uploader.parseRequest(request); Iterator fileItemsIterator = fileItemsList.iterator();...您可能想看看 systempuntoout 的解决方案using apache fileupload on GAE，它使用流媒体而不是我已经尝试过的，它可以工作。