找不到Struts调度程序

Question

ERROR comes like :

The Struts dispatcher cannot be found. This is usually caused by using Struts tags without the associated filter. Struts tags are only usable when the request has passed through its servlet filter, which initializes the Struts dispatcher needed for this tag.

MY struts.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" 

    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">

<display-name>Struts2 Login</display-name>

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

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

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

my web.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>
<constant name="struts.action.excludePattern" value="/ServletToExcludeFromStruts*"    />
<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<constant name="struts.devMode" value="true" />
<package name="helloworld" extends="struts-default">

    <action name="hello" class="com.struts.action.HelloWorldAction"
        method="execute">
        <result name="success">/HelloWorld.jsp</result>
    </action>
    </package>
 </struts>

and required jar file...[correct me if i am wrong]

commons-logging-1.0.4.jar
freemarker-2.3.8.jar
ognl-2.6.11.jar
struts2-core-2.0.11.jar
xwork-2.0.4.jar
commons-collections-3.0.jar
commons-fileupload-1.2.1.jar
commons-lang-2.4.jar
commons-io-1.3.2.jar
javassist-3.0.jar

Answer 1

Your web.xml and struts.xml are fine.

The JARs versions are a little different from the required dependencies for Struts 2.0 :

xwork should be 2.0. 7 , commons-io should be 1. 0 , and so on.

Btw, since it seems you are starting today with a new Struts2 project, I STRONGLY suggest you to start with the latest Struts2 libraries for at least the following reasons:

1. There is absolutely not a single reason to use a 6 years old library; if your company has this rule, then fight with your bosses to change this rule, especially for the following arguments;
2. Struts2 versions before 2.3.15.3 are affected by a serious security bug ;
3. Struts2 has evolved significantly in terms of power, efficiency, speed, bugfixing, and has deprecated several old and buggy libraries, like Struts2-Dojo and the aforementioned FilterDispatcher (since Struts 2.1.3 , you must use the new filter, that is the StrutsPrepareAndExecuteFilter , as written in the FilterDispatcher documentation )
4. With new Struts2 versions, you can use the new plugins out there, that will add real values to your webapp, especially:
   • Struts2 Convention Plugin
   • Struts2 jQuery Plugin (take a look at the showcase )
   • Struts2 JSON Plugin

Then start a new project with the latest libraries (currently 2.3.16.1 ), preferibly with Maven, or either by hand paying attention to the required dependencies and their versions .

Download a Release of Apache Struts

Answer 2

我想你已经交换了两个文件（struts.xml和web.xml）的内容，这就是你收到这个错误的原因。