Spring MVC "duplicates" parts of the URL

Question

I have a simple @Controller within a spring-mvc environment. This is the Controller:

@Controller
public class MessageController {
    private static Logger LOG = LoggerFactory
            .getLogger(MessageController.class);

    @RequestMapping(value = "/messages/{userId}/{messageId}", method = RequestMethod.GET)
    public Message getMessage(@PathVariable("userId") String uid,
            @PathVariable("messageId") String msgid) {
        LOG.trace("GET /message/{}/{}", uid, msgid);
        return new Message();
    }
}

This is the servlet-mapping in web.xml:

<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
             http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
         version="2.4">

    <display-name>Messaging Service</display-name>

    <servlet>
        <servlet-name>messaging</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>messaging</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

</web-app>

When I start the app via jetty and run a request against /messages/abc/def, I get the following log:

INFO: Mapped "{[/messages/{userId}/{messageId}],methods=[GET],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public ....Message ....MessageController.getMessage(java.lang.String,java.lang.String)
WARNING: No mapping found for HTTP request with URI [/messages/abc/messages/abc/def] in DispatcherServlet with name 'messaging'

What did I do wrong here? The request definitely only contains /messages/abc/def, why is this internally translated to /messages/abc/messages/abc/def?

Answer 1

I guess it's related to default view name resolution.

If you want a value returned by your handler method to be encoded as response body (in JSON, XML, etc), you need to annoate the method with @ResponseBody, or annotate the whole controller with @RestController (in Spring 4.x).

Otherwise, Spring tries to render a view with your return as model attribute. And since you didn't provide a name of a view to render, Spring tries to deduce it from request URL.