为什么Spring DispatcherServlet找不到我的控制器方法？

Question

Let's say I have the following Spring controller:

@Controller
public class FooController
{
    @RequestMapping(value = "/foo", method = RequestMethod.GET, headers = { "Content-Type=text/plain" })
    @ResponseBody
    public String foo(String bar)
    {
        return "Bar is " + bar;
    }
}

Here's the associated web.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
     id="WebApp_ID"
     version="2.5">
  <display-name>Foo</display-name>
  <servlet>
    <servlet-name>FooServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/servlet.xml</param-value>
    </init-param>
    <load-on-startup>0</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>FooServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
  </welcome-file-list>
</web-app>

And here's the associated servlet.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
  <mvc:annotation-driven/>
  <bean id="FooController" class="foo.FooController"/>
</beans>

FYI, I'm using version 3.0.5 of Spring Framework. I know this is an old version, but it's a constraint that I have to work under.

So I deploy the WAR file (eg FooApp.war) built from the above to Tomcat (version 7.0.67). Everything starts up fine. But when I navigate to http://localhost:8080/FooApp/foo?bar=baz , I get a 404 error in the browser and the following in the Tomcat console:

Apr 28, 2016 9:43:33 AM org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver handleNoSuchRequestHandlingMethod
WARNING: No matching handler method found for servlet request: path '/foo', method 'GET', parameters map['bar' -> array<String>['baz']]

So my question is, what am I doing wrong in my configuration that's causing this issue? I'm sure it's something, but I'm having trouble figuring out what it is.

Edit: Removed the SimpleUrlHandlerMapping , per M. Deinum's comment.

Answer 1

I downloaded the example project from here and started looking at what was different between it and my test project. I finally narrowed it down to the presence of headers = { "Content-Type=text/plain" } in the @RequestMapping annotation in my controller method. After removing it, everything works.

Answer 2

Add "context:component-scan base-package="package name" /" to servlet.xml. This will enable auto scanning of your controller.