我正在使用Spring框架,但不太熟悉它.我正在编写一个REST API,特别是一个POST方法,用于处理文件上传的文件是可选的.

我试图简化方法,但仍然有问题.这就是我所拥有的

@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).我尝试用HttpServletRequest参数替换@RequestParam,产生相同的结果.

我使用以下堆栈跟踪得到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)

我在网上搜索时发现只有一篇帖子,并且它在春天谈论这可能是一个错误.我一直坚持这个问题一段时间了,非常感谢一些帮助.

谢谢

解决方法:

这是我最终得到的解决方案.

@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
    }

}