Java – Spring MVC did not detect my Controller

Spring MVC did not detect my Controller… here is a solution to the problem.

Spring MVC did not detect my Controller

I have a Spring MVC project with the following files:

/src/main/webapp/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
      <display-name>Archetype Created Web Application</display-name>
       <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/appconfig-root.xml</param-value>
    </context-param>

<servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value></param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

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

<listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

There are also 2 configuration files:

/src/main/webapp/WEB-INF/appconfig-root.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns="http://www.springframework.org/schema/beans"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

<import resource="appconfig-mvc.xml"/>

<context:component-scan base-package="yc.servlets"/>

<!--<context:property-placeholder location="classpath:application.properties"/>-->
</beans>

/src/main/webapp/WEB-INF/appconfig-mvc.xml

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

<mvc:annotation-driven/>

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

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

<property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>
</beans>

and the class that contains my Controller:

package yc.servlets;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class TestPage {

@RequestMapping(value = "/hello_there", method = RequestMethod.GET)
    public String hello() {
        return "hello";
    }
}

I

thought this was enough for Spring MVC to work, but when I type localhost:8888 in my browser, I get a 404 error.

localhost:8888/hello_there also gives a 404 error.

Solution

Hello, you are returning “hello” in the Controller and it will find the hello .jsp
If it can’t find it, it throws a 404 HTTP error

When you configure InternalViewResolver:

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

<property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>

It tries to look in /WEB-INF/jsp/hello.jsp, so when you return the string “hello” in the controller:

@RequestMapping(value = "/hello_there", method = RequestMethod.GET)
    public String hello() {
        return "hello";
    }

It will add a suffix “.jsp” to “hello”, and it will try to find “hello.jsp” because if it can’t find it it will throw a 404

You can change the @Controller to @RestController, which implicitly adds a @ResponseBody comment, and see if it returns “hello” in the response

Also, if this doesn’t help you, you can change it:

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

to this:

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

If it still works now, try the next step:

Try this URL:

localhost:8080/yourApplicationName/hello_there

The default conext-path here is your application name
If you go to TOMCAT_HOME/webapps/

You will find that there is no app under the root directory

That’s why localhost:8080/… The reason why it can’t be found

You can resolve this issue in two ways:

1.Find your application deployed and copy to root folder in 
    TOMCAT_HOME/webapps/ROOT
 2.See the name of your application in  TOMCAT_HOME/webapps/ 
   and call url : localhost:8080/yourAppName/hello_world   

Thanks

Related Problems and Solutions