上传文件提交后报错如下：

HTTP Status 500 – Internal Server Error
Type 异常报告

消息 Request processing failed; nested exception is com.sun.jersey.api.client.UniformInterfaceException: PUT http://localhost:8090/uploads/e12da6293536451c88ffbfb6bbdf030e_20.jpg returned a response status of 409 Conflict

描述 服务器遇到一个意外的情况，阻止它完成请求。

Exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.sun.jersey.api.client.UniformInterfaceException: PUT http://localhost:8090/uploads/e12da6293536451c88ffbfb6bbdf030e_20.jpg returned a response status of 409 Conflict
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:986)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
Root Cause

com.sun.jersey.api.client.UniformInterfaceException: PUT http://localhost:8090/uploads/e12da6293536451c88ffbfb6bbdf030e_20.jpg returned a response status of 409 Conflict
    com.sun.jersey.api.client.WebResource.voidHandle(WebResource.java:709)
    com.sun.jersey.api.client.WebResource.put(WebResource.java:208)
    com.devTest.controller.UploadController.testServerUpload(UploadController.java:100)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:498)
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:871)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:777)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
Note 主要问题的全部 stack 信息可以在 server logs 里查看

Apache Tomcat/9.0.26

问题原因：
controller方法定义了文件服务器上传文件目录：String path = "http://localhost:8090/uploads/";
但是未在target资源目录下添加对应的目录uploads（用来放上传的文件资源），添加上即可成功上传。