Spring DispatcherServlet matches for wrong url-pattern - spring

Question

I have following configuration in the Spring based project -
web.xml -
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/api/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/img/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/test</url-pattern>
</servlet-mapping>
Handler mapping from spring-servlet.xml -
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping">
<property name="alwaysUseFullPath" value="true" />
</bean>
and Spring Controller as -
#RestController
public class TestController {
#PostMapping("/test")
public String test() {
return "hello";
}
}
Now when I send request to
GET http://localhost:8080/test
I get response as hello which is fine but when I send request on following URL's -
GET http://localhost:8080/api/test
GET http://localhost:8080/img/test
then also I get hello response i.e. controller code gets executed for above mentioned wrong URLs.
Is there anything wrong in the configuration or it's expected behaviour?

Answer 1

The mapping of an URL to a handler (a method) in Spring MVC is a two-step process:
first the servlet container must decide whether to forward the request to the DispatcherServlet according to the <servlet-mapping>,
then the DispatcherServlet consults its HandlerMappings to see which one matches the request. A HandlerMapping can do anything, but usually calls UrlPathHelper#getLookupPathForRequest to transform the request into a path.
The default behavior of the UrlPathHelper depends on the <servlet-mapping> used:
if you used an exact mapping as in the case of /test, a request for /test will give a path of /test,
if you used a prefix mapping /api/*, a request for /api/foo/bar will result in a path of only /foo/bar.
As mentioned in the comment by M. Deinum you need to set the alwaysUseFullPath property to true on the RequestMappingHandlerMapping instance used by the DispatcherServlet.
In your XML application context configuration you define a bean of class RequestMappingHandlerMapping, while you should overwrite the bean used by the DispatcherServlet. Therefore you need to use the same id internally used by Spring:
<mvc:annotation-driven/>
<bean id="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"
class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping">
<property name="alwaysUseFullPath" value="true"/>
</bean>
Remark: This solution should work unless you invert the order of the definitions in your XML. In such a case the default definition will overwrite yours. Set the logger org.springframework.beans.factory.support do DEBUG to check which definition overwrites the other. In one case you get:
Overriding user-defined bean definition for bean 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping' with a framework-generated bean definition: ...
in the other:
Overriding bean definition for bean 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping' with a different definition: ...