Struts 2 : There is no Action mapped for namespace [/]

Question

I am new to Struts 2 and I have been following a video tutorial on Struts 2(Koushik). I have created the Struts.xml, the action class and JSPs as same as created in the tutorial. But it gives the following exception.

Exception:

Jan 13, 2014 9:30:48 PM org.apache.struts2.dispatcher.Dispatcher warn
WARNING: Could not find action or result: /Struts2Starter/getTutorial.action
There is no Action mapped for namespace [/] and action name [getTutorial] associated with context path [/Struts2Starter]. - [unknown location]
    at com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:185)
    at org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:63)
    at org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:37)
    at com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:58)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:552)
    at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

Struts.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

    <package name="default" extends="struts-default">
        <action name="getTutorial" class="org.koushik.javabrains.action.TutorialAction">
            <result name="success">/success.jsp</result>
            <result name="error">/error.jsp</result>
        </action>

    </package>

</struts>

Web.xml

<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>Struts2Starter</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

  <filter>
    <filter-name>struts2</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
  </filter>

  <filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

</web-app>

TutorialAction.java (Action class that I'm using)

package org.koushik.javabrains.action;

public class TutorialAction {


    public String execute(){
        System.out.println("Hello from execute");
        return "success";
    }
}

Project structure

success.jsp and error.jsp are normal jsp files with some text. I did a lot of things to resolve this issue by googling. But nothing didn't solve this. Please let me know if anyone knows what's behind this. I highly appreciate it. :)

Answer 1

The message from error clearly says that

no Action mapped for namespace [/] and action name [getTutorial] associated with context path [/Struts2Starter]

This means that action configuration is not available at runtime. Check out the config-browser plugin to debug configuration issues.

To map correctly url to the action two parameters are required: the action name and namespace.

Struts loads xml configuration on startup and it should know the location of the struts.xml. By default it's looking on classpath to find a file with known name like struts.xml. Then it parses document and creates a runtime configuration. This configuration is used to find appropriate configuration element for the action url. If no such element is found during request, the 404 error code is returned with the message: There is no Action mapped for namespace and action name.

Also this message contains a namespace and action names used to find the action config. Then you can check your configuration settings in struts.xml. Sometimes the action name and namespace, stored in ActionMapping point to the wrong action. These values are determined by the ActionMapper which could have different implementation, used by plugins.

There's also another setting that might affect this mapper and mapping, but the point is the same if you get this message then URL is used didn't map any action config in runtime configuration. If you can't realize which URL you should use, you might try config-browser plugin to see the list of URLs available to use.