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.

Answer 2

将Struts.xml命名约定重命名为struts.xml将起作用。

Answer 3

change your Struts.xml and put <constant name="struts.devMode" value="true" /> in struts.xml Development mode or devMode it enables extra debugging and helps indebugging try below code

   <?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>

         <constant name="struts.devMode" value="true" />
        <package name="default" namespace="/" 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>

Answer 4

你只需要检查动作名称在任何地方都是不变的......我也有同样的问题，我通过删除命名空间解决了同样的问题，因为它不是必需的，我看到你没有提到，而且我在 loginpage.jsp 和 struts 上有不同的动作名称。 xml 页面 .. 所以只要看看你的动作名称

Answer 5

Your JSP file should not be under the WEB-INF folder, but should be under the web folder. I've attached an image to show you the right hierarchy.

Folder System

Answer 6

I just did the tutorial and had the same problem. It turns out the problem was the struts.xml file was in the wrong location. Make sure your struts.xml file is located here: /Struts2Starter/src/struts.xml