Spring MVC 3: Returning XML through @ResponseBody

Question

Pardon me for posting this noob question, but I have been debugging this problem for quite awhile now. I'm having a little problem trying to get the response to return the XML based on the object:-

@RequestMapping(value = "/mylink", method = RequestMethod.GET)
public @ResponseBody SomeObject doIt() {
    ...
}

Right now, even though that API is called, my client side does not receive the XML response at all. I have been reading a few places and it seems like I need to configure the XML marshaller or somesort of XML resolvers, but I'm not sure how to integrate that piece into my existing configuration. I currently have the following configuration in my servlet.xml:-

<context:component-scan base-package="ss.controller" />

<mvc:annotation-driven />

<mvc:resources location="/resources/" mapping="/resources/**" />

<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/jsp/app/" />
    <property name="suffix" value=".jsp" />
</bean>

Can someone kindly post some sample configurations on how I might go about in configuring my servlet.xml to get this working? Thanks much.

Answer 1

This can be done by adding the following bit of magic to the Spring context (see docs):

<mvc:annotation-driven/>

which amongst other things, provides:

Support for reading and writing XML, if JAXB is present on the classpath.

If JAXB is detected (i.e. if you're on Java6, or otherwise have some JAXB implementation on your classpath), this will register a Jaxb2RootElementHttpMessageConverter with the context, and will provide the ability to spit out XML from the return value of the @ResponseBody-annotated method.

Note: Your question sort-of suggested using a ViewResolver for rendering the XML, but this isn't necessary. The @ResponseBody annotation is designed to bypass the view layer altogether.

Answer 2

I solved this problem with Spring 3 mvc without MarshallingView

@RequestMapping(value = "actionName.xml", method = RequestMethod.GET)
public HttpEntity<byte[]> getXml(ModelMap map, HttpServletResponse response) {

    String xml = generateSomeXml();

    byte[] documentBody = xml.getBytes();

    HttpHeaders header = new HttpHeaders();
    header.setContentType(new MediaType("application", "xml"));
    header.setContentLength(documentBody.length);
    return new HttpEntity<byte[]>(documentBody, header);
}

that's all. greetings

Answer 3

What I do when I want to return an XML representation of objects using spring is that I define a MarshallingView, e.g.,

<!-- XML view using a JAXB marshaller -->
<bean id="jaxbView" class="org.springframework.web.servlet.view.xml.MarshallingView">
    <constructor-arg>
        <bean id="jaxb2Marshaller" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
            <property name="classesToBeBound">
                <list>
                    <value>com.company.AClass</value>
                </list>
            </property>
        </bean>
    </constructor-arg>
</bean>

<!-- Resolve views based on string names -->
<bean class="org.springframework.web.servlet.view.BeanNameViewResolver"/>

Note that there is a whole world of alternatives to jaxb. The next step is

@RequestMapping("/request")
public ModelAndView sample() {
    return new ModelAndView("jaxbView", "data", "data_to_be_turned_into_xml");
}

Or if you want to use the ResponseBody annotation, it would look like:

@RequestMapping("/request")
@ResponseBody
public void sample() {
    return "data_to_be_turned_into_xml"
}

Note that this requires defining a HttpMessageConverter. See the spring documentation for a perfect sample on how to do this.

Answer 4

You will probably either have to use an XML Marshalling View or configure a MarshallingHttpMessageConverter.

Here's a short Reference about using @ResponseBody with converters.