Java 带多部分文件上载的Spring REST API不适用于可选参数

我正在使用Spring框架，但对它不太熟悉。我正在编写一个RESTAPI，特别是一个POST方法，用于处理可选文件的文件上载

我试图简化这个方法，但仍然有问题。这是我的

@RequestMapping(method = RequestMethod.POST, value="/items")
public String create(@RequestParam(value="file", required=false) MultipartFile file) {
    return "Create";
}

当我在表单请求中包含一个文件时，该方法工作正常，但是当我没有文件时（因为我希望它是可选的）。我已经尝试用

HttpServletRequest

参数替换

@RequestParam

，得到了相同的结果

我在以下堆栈跟踪中得到一个500错误：

java.io.IOException: org.apache.tomcat.util.http.fileupload.FileUploadException: Stream ended unexpectedly
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:973)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
</pre></p><p><b>root cause</b> <pre>org.springframework.web.multipart.MultipartException: Could not parse multipart servlet request; nested exception is java.io.IOException: org.apache.tomcat.util.http.fileupload.FileUploadException: Stream ended unexpectedly
    org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.parseRequest(StandardMultipartHttpServletRequest.java:99)
    org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.&lt;init&gt;(StandardMultipartHttpServletRequest.java:77)
    org.springframework.web.multipart.support.StandardServletMultipartResolver.resolveMultipart(StandardServletMultipartResolver.java:76)
    org.springframework.web.servlet.DispatcherServlet.checkMultipart(DispatcherServlet.java:1067)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:906)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
</pre></p><p><b>root cause</b> <pre>java.io.IOException: org.apache.tomcat.util.http.fileupload.FileUploadException: Stream ended unexpectedly
    org.apache.catalina.connector.Request.parseParts(Request.java:2806)
    org.apache.catalina.connector.Request.parseParameters(Request.java:3096)
    org.apache.catalina.connector.Request.getParameter(Request.java:1145)
    org.apache.catalina.connector.RequestFacade.getParameter(RequestFacade.java:382)
    org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:70)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
</pre></p><p><b>root cause</b> <pre>org.apache.tomcat.util.http.fileupload.FileUploadException: Stream ended unexpectedly
    org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:311)
    org.apache.catalina.connector.Request.parseParts(Request.java:2737)
    org.apache.catalina.connector.Request.parseParameters(Request.java:3096)
    org.apache.catalina.connector.Request.getParameter(Request.java:1145)
    org.apache.catalina.connector.RequestFacade.getParameter(RequestFacade.java:382)
    org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:70)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
</pre></p><p><b>root cause</b> <pre>org.apache.tomcat.util.http.fileupload.MultipartStream$MalformedStreamException: Stream ended unexpectedly
    org.apache.tomcat.util.http.fileupload.MultipartStream.readHeaders(MultipartStream.java:480)
    org.apache.tomcat.util.http.fileupload.FileUploadBase$FileItemIteratorImpl.findNextItem(FileUploadBase.java:889)
    org.apache.tomcat.util.http.fileupload.FileUploadBase$FileItemIteratorImpl.&lt;init&gt;(FileUploadBase.java:854)
    org.apache.tomcat.util.http.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:259)
    org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:283)
    org.apache.catalina.connector.Request.parseParts(Request.java:2737)
    org.apache.catalina.connector.Request.parseParameters(Request.java:3096)
    org.apache.catalina.connector.Request.getParameter(Request.java:1145)
    org.apache.catalina.connector.RequestFacade.getParameter(RequestFacade.java:382)
    org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:70)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

java.io.IOException:org.apache.tomcat.util.http.fileupload.FileUploadException:流意外结束
org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:973）
org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java:863）
javaservlet.http.HttpServlet.service（HttpServlet.java:646）
org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:837）
javaservlet.http.HttpServlet.service（HttpServlet.java:727）
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:77）
org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）
根本原因org.springframework.web.multipart.MultipartException:无法解析多部分servlet请求；嵌套异常为java.io.IOException:org.apache.tomcat.util.http.fileupload.FileUploadException:流意外结束
org.springframework.web.multipart.support.StandardMultipartTTpServletRequest.parseRequest（StandardMultipartTTpServletRequest.java:99）
org.springframework.web.multipart.support.StandardMultipartTTpServletRequest.init（StandardMultipartTTpServletRequest.java:77）
org.springframework.web.multipart.support.StandardServletMultipartResolver.resolveMultipart（StandardServletMultipartResolver.java:76）
org.springframework.web.servlet.DispatcherServlet.checkMultipart（DispatcherServlet.java:1067）
org.springframework.web.servlet.DispatcherServlet.doDispatch（DispatcherServlet.java:906）
org.springframework.web.servlet.DispatcherServlet.doService（DispatcherServlet.java:870）
org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:961）
org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java:863）
javaservlet.http.HttpServlet.service（HttpServlet.java:646）
org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:837）
javaservlet.http.HttpServlet.service（HttpServlet.java:727）
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:77）
org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）
根本原因java.io.IOException:org.apache.tomcat.util.http.fileupload.FileUploadException:流意外结束
org.apache.catalina.connector.Request.parseParts（Request.java:2806）
org.apache.catalina.connector.Request.parseParameters（Request.java:3096）
org.apache.catalina.connector.Request.getParameter（Request.java:1145）
org.apache.catalina.connector.RequestFacade.getParameter（RequestFacade.java:382）
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:70）
org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）
根本原因org.apache.tomcat.util.http.fileupload.FileUploadException:流意外结束
org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest（FileUploadBase.java:311）
org.apache.catalina.connector.Request.parseParts（Request.java:2737）
org.apache.catalina.connector.Request.parseParameters（Request.java:3096）
org.apache.catalina.connector.Request.getParameter（Request.java:1145）
org.apache.catalina.connector.RequestFacade.getParameter（RequestFacade.java:382）
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:70）
org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）
根本原因org.apache.tomcat.util.http.fileupload.MultipartStream$MalformedStreamException:流意外结束
org.apache.tomcat.util.http.fileupload.MultipartStream.readHeaders（MultipartStream.java:480）
org.apache.tomcat.util.http.fileupload.FileUploadBase$fileiteratorimpl.findNextItem（FileUploadBase.java:889）
org.apache.tomcat.util.http.fileupload.FileUploadBase$fileiteratorimpl.init（FileUploadBase.java:854）
org.apache.tomcat.util.http.fileupload.FileUploadBase.getItemIterator（FileUploadBase.java:259）
org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest（FileUploadBase.java:283）
org.apache.catalina.connector.Request.parseParts（Request.java:2737）
org.apache.catalina.connector.Request.parseParameters（Request.java:3096）
org.apache.catalina.connector.Request.getParameter（Request.java:1145）
org.apache.catalina.connector.RequestFacade.getParameter（RequestFacade.java:382）
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:70）
org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）

我在网上的搜索中只找到了一篇帖子，上面说这可能是春天的一个bug。这个问题我已经解决了一段时间了，非常感谢您的帮助

---

谢谢

这是我最后得到的解决方案

@RequestMapping（method=RequestMethod.POST，value=“/object”）
ResponseEntity创建（@RequestParam（“is_文件”）布尔isFile，HttpServletRequest请求）{
if（isFile）{
MultipartTTpServletRequest multipartRequest=（MultipartTTpServletRequest）请求；
MultipartFile file=multipartrequues
@RequestMapping(method = RequestMethod.POST, value = "/object")
ResponseEntity<Object> create(@RequestParam("is_file") boolean isFile, HttpServletRequest request) {
    if(isFile) {
      MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
      MultipartFile file = multipartRequest.getFile("file");
    } else{
      // You can add other parameters (as long as it isn't a multipart parameter) and do other stuff here
    }

@RequestMapping(method = RequestMethod.POST)
public ResponseEntity<String> upload(@RequestPart(value = "name", required = false) String name,
                                     @RequestPart(value = "file", required = false) MultipartFile file) 

@RequestMapping(method = RequestMethod.POST, value="/items")
public String create(@RequestParam(value ="file", required=false) MultipartFile file) {
    return "Create";
}