How to invoke controller methods in Spring MVC

Question

I want to hit the readTasks method of my controller when navigating to the root of my web app. I have set a breakpoint in the method but I am not hitting it when debugging on the server. I am using Eclipse.

I nagivate to: http://localhost:8080/ToDoList/ and I see my index page but the controller method is not invoked.

My Controller:

import java.util.List;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TaskController {

    @RequestMapping(value = "/", method = RequestMethod.GET)
    public List<TaskEntity> readTasks() 
    {
        TaskEntityDao tasks = new TaskEntityDaoImpl();
        return tasks.getAllTasks();
    }
}

My web.xml:

<web-app version="2.4"
     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" >

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>

    <servlet>
        <servlet-name>Dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>Dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

I believe I am missing some configuration to initialise the controller, but I am not sure how to go about it. Do I need a configuration file that contains initialisation of every single controller in my application?

Answer 1

You'll need to write a Spring configuration file which includes a component scan for the package that your controller is located in. This tells Spring to initialise this controller when the Spring context loads. You then need to point your servlet to this configuration:

<servlet>
    <servlet-name>Dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
    <init-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>/WEB-INF/spring/dispatcher-config.xml</param-value>
    </init-param>
</servlet>

Answer 2

You need to made a Spring MVC configuration, in your web.xml :

<servlet>
    <servlet-name>Dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
    <init-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>/WEB-INF/spring/mvc-dispatcher-servlet.xml</param-value>
    </init-param>
</servlet>

Then make mvc-dispatcher-servlet.xml under WEB-INF folder.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       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
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd ">

    <!-- enable to scan spring annotations, specify on web package -->
    <context:component-scan base-package="id.swhp.spring.web"/>
    <!-- Enable Spring MVC Anotations -->
    <mvc:annotation-driven/>

</beans>