SpringMVC多部分响应

Question

我试图编写完整的多部分流，从客户端使用Spring restTemplate发送多部分请求，从服务器端自动将不同部分解析为对象（我使用JAXB进行对象封送），并以多部分形式返回响应。

我能够实现几乎所有的流，但是我不能从spring Controller中用jaxb对象发送多部分响应。

@RequestMapping(value="/putuser",method=RequestMethod.POST)
@ResponseBody
public MultiValueMap<String, Object> getUser(@RequestBody User user) throws IOException, JAXBException {
    }
    user.setName("new");
    MultiValueMap<String, Object> form = new LinkedMultiValueMap<String, Object>();  
    form.add("user", user);
    form.add("file", new FileSystemResource("/tmp/1.1")); 
    return form;
}

java.lang.ClassCastException: org.springframework.core.io.FileSystemResource cannot be cast to java.lang.String
    at org.springframework.http.converter.FormHttpMessageConverter.writeForm(FormHttpMessageConverter.java:233)
    at org.springframework.http.converter.FormHttpMessageConverter.write(FormHttpMessageConverter.java:197)
    at org.springframework.http.converter.FormHttpMessageConverter.write(FormHttpMessageConverter.java:73)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:148)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:90)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:189)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:69)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:746)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:687)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:915)

<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
       <bean class="org.springframework.http.converter.FormHttpMessageConverter">
                <property name="partConverters">
                    <list>
                        <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter" />
                        <bean class="org.springframework.http.converter.StringHttpMessageConverter" />
                        <bean class="org.springframework.http.converter.ResourceHttpMessageConverter" />
                        <bean class="org.springframework.http.converter.xml.Jaxb2RootElementHttpMessageConverter" />
                    </list>
                </property>
        </bean>
   </mvc:message-converters>
</mvc:annotation-driven>

试图使he FormHttpMessageConverter正确地编写部分，但这没有帮助

是否有任何方法使Spring发送不同类型的零件正确的多部分响应？

Answer 1

您需要将响应的Content-Type header设置为适当的值。FormHttpMessageConverter依赖于Content-Type来确定是否需要将响应强制转换为String或其他类型。

@RequestMapping(value="/putuser",method=RequestMethod.POST)
@ResponseBody
public MultiValueMap<String, Object> getUser(@RequestBody User user, HttpServletResponse httpResponse) throws IOException, JAXBException {
    }
    user.setName("new");
    MultiValueMap<String, Object> form = new LinkedMultiValueMap<String, Object>();  
    form.add("user", user);
    form.add("file", new FileSystemResource("/tmp/1.1")); 
    httpResponse.setContentType(MediaType.MULTIPART_FORM_DATA_VALUE); // <-- IMPORTANT
    return form;
}