There is no Action mapped for namespace / and action name HelloWorld

Question

I am trying to run a simple struts 2 HelloWorld application ,when i run it ,says "There is no Action mapped for namespace / and action name HelloWorld.Can somebody please help.

WARNING: Could not find action or result
There is no Action mapped for namespace / and action name HelloWorld. - [unknown location]
    at com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:189)
    at org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:61)
    at org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:39)
    at com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:58)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
    at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:434)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Unknown Source)

Answer 1

请参阅此链接： http : //www.vaannila.com/struts-2/struts-2-example/struts-2-hello-world-example-1.html

Answer 2

Maybe you have made a mistake in the struts.xml file. There are several ways to configure this file; here is an example:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
    <package name="default" extends="struts-default">
        <action name="helloWorld" class="controller.HelloWorld">
            <result name="success">/HelloWorld.jsp</result>

        </action>
    </package>
</struts>

If you do this in this way just make sure that you have to call action from the jsp by Action name only; You do not need to write .action : that will cause error.

This could answer your question.

Answer 3

->检查action是否映射到struts文件->jsp中的action名，struts.xml中和action类名都一模一样->struts-config.xml中的action映射是否在某个包下，然后include url 中的包（例如，在提交表单时，url 必须包含包的名称）

Answer 4

更常见的是，即使struts.xml 没有任何问题，但当struts 获取操作名称错误时，问题在于jsp 文件中缺少标记lib 定义。