Struts2 severe: Dispatcher initialization failed java. Lang. runtimeexception

Severe: Dispatcher initialization failed
Java. Lang. runtimeexception: Java. Lang. Reflect. invocationtargetexception
At com. opensymphony. xwork2.inject. containerimpl $ methodinjector. Inject (containerimpl. Java: 295)
At com. opensymphony. xwork2.inject. containerimpl $ constructorinjector. Construct (containerimpl. Java: 431)
At com. opensymphony. xwork2.inject. containerbuilder $5. Create (containerbuilder. Java: 207)
At com. opensymphony. xwork2.inject. Scope $2 $1. Create (scope. Java: 51)
At com. opensymphony. xwork2.inject. containerbuilder $3. Create (containerbuilder. Java: 93)
At com. opensymphony. xwork2.inject. containerbuilder $7. Call (containerbuilder. Java: 487)
At com. opensymphony. xwork2.inject. containerbuilder $7. Call (containerbuilder. Java: 484)
At com. opensymphony. xwork2.inject. containerimpl. callincontext (containerimpl. Java: 574)
At com. opensymphony. xwork2.inject. containerbuilder. Create (containerbuilder. Java: 484)
At com. opensymphony. xwork2.config. impl. defaultconfiguration. createbootstrapcontainer (defaultconfiguration. Java: 252)
At com. opensymphony. xwork2.config. impl. defaultconfiguration. reloadcontainer (defaultconfiguration. Java: 193)
At com. opensymphony. xwork2.config. configurationmanager. getconfiguration (configurationmanager. Java: 66)
At org. Apache. struts2.dispatcher. Dispatcher. init_preloadconfiguration (dispatcher. Java: 371)
At org. Apache. struts2.dispatcher. Dispatcher. INIT (dispatcher. Java: 415)
At org. Apache. struts2.dispatcher. Ng. initoperations. initdispatcher (initoperations. Java: 69)
At org. Apache. struts2.dispatcher. Ng. Filter. strutsprepareandexecutefilter. INIT (strutsprepareandexecutefilter. Java: 51)
At org. Apache. Catalina. Core. applicationfilterconfig. getfilter (applicationfilterconfig. Java: 275)
At org. Apache. Catalina. Core. applicationfilterconfig. setfilterdef (applicationfilterconfig. Java: 397)
At org. Apache. Catalina. Core. applicationfilterconfig. <init> (applicationfilterconfig. Java: 108)
At org. Apache. Catalina. Core. standardcontext. filterstart (standardcontext. Java: 3800)
At org. Apache. Catalina. Core. standardcontext. Start (standardcontext. Java: 4450)
At org. Apache. Catalina. Core. containerbase. Start (containerbase. Java: 1045)
At org. Apache. Catalina. Core. standardhost. Start (standardhost. Java: 722)
At org. Apache. Catalina. Core. containerbase. Start (containerbase. Java: 1045)
At org. Apache. Catalina. Core. standardengine. Start (standardengine. Java: 443)
At org. Apache. Catalina. Core. standardservice. Start (standardservice. Java: 516)
At org. Apache. Catalina. Core. standardserver. Start (standardserver. Java: 710)
At org. Apache. Catalina. startup. Catalina. Start (Catalina. Java: 583)
At sun. Reflect. nativemethodaccessorimpl. invoke0 (native method)
At sun. Reflect. nativemethodaccessorimpl. Invoke (nativemethodaccessorimpl. Java: 39)
At sun. Reflect. delegatingmethodaccessorimpl. Invoke (delegatingmethodaccessorimpl. Java: 25)
At java. Lang. Reflect. method. Invoke (method. Java: 597)
At org. Apache. Catalina. startup. Bootstrap. Start (Bootstrap. Java: 288)
At org. Apache. Catalina. startup. Bootstrap. Main (Bootstrap. Java: 413)
Caused by: Java. Lang. Reflect. invocationtargetexception

1. Check the Lib package

Commons-fileupload-1.2.1.jar,
Commons-io-1.3.2.jar
Commons-logging-1.0.4.jar
Freemarker-2.3.16.jar
Ognl-3.0.jar
Struts2-core-2.2.1.jar
Xwork-core-2.2.1.jar

Note that there was no commons-fileupload-1.2.1.jar before 2.1,

2. If the struts2 version is earlier than 2.1

When configuring the filter in Web. XML, it should be as follows:

<Web-app>
<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>
</Web-app>

If the struts2 version is later than 2.1

Web. xml configuration

<Web-app>
<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>
3,

When using struts-2.2.1, You need to introduce the javassist-3.7.ga.jar, and this is not in Struts-2.2.1 \ Lib, you need to find in Struts-2.2.1 \ apps \ struts2-blank-2.2.1.war Lib.
Struts. xml file header is copied from any file in struts2-2.2.1-all \ Struts-2.2.1 \ apps!