我正在使用Struts2构建我的第一个应用程序，并且在运行应用程序时遇到ClassNotFoundException。
只是为了一些背景。我使用此链接下载了最新的Struts2 2.5.29版本(尝试使用完全分发和仅基本依赖项版本，但两个版本都获得了相同的ClassNotFoundException(：https://struts.apache.org/download.cgi
下载Struts2库后，我将jar文件添加到我的项目中，遵循Java Brains的Struts2设置教程(该教程要求您将jar文件同时添加到项目类路径和WEB-INF lib文件夹中(：https://www.youtube.com/watch?v=LhjEgxJ080g&list＝PLB7BB551126EDD5E0&索引=3
以下是我的Java文件：
struts.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
"http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
<package name="default" extends="struts-default">
<action name="getTutorial" class="com.struts.action.TutorialAction">
<result name="success">/success.jsp</result>
<result name="failure">/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://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
<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.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
教程操作：
package com.struts.action;
public class TutorialAction {
public String execute() {
System.out.println("Hello from execute");
return "success";
}
}
这是我得到的错误：
Mar 09, 2022 10:01:32 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-nio-8081"]
Mar 09, 2022 10:01:32 AM org.apache.catalina.startup.Catalina load
INFO: Server initialization in [656] milliseconds
Mar 09, 2022 10:01:32 AM org.apache.catalina.core.StandardService startInternal
INFO: Starting service [Catalina]
Mar 09, 2022 10:01:32 AM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet engine: [Apache Tomcat/9.0.58]
Mar 09, 2022 10:01:37 AM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
Mar 09, 2022 10:01:37 AM org.apache.catalina.core.ApplicationContext log
INFO: No Spring WebApplicationInitializer types detected on classpath
Mar 09, 2022 10:01:38 AM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
ERROR StatusLogger Log4j2 could not find a logging implementation. Please add log4j-core to the classpath. Using SimpleLogger to log to the console...
Mar 09, 2022 10:01:40 AM org.apache.catalina.core.StandardContext filterStart
SEVERE: Exception starting filter [struts2]
java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1407)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1215)
at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:534)
at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:515)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:251)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:102)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4613)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5256)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1396)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1386)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:919)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:835)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1396)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1386)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:919)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:263)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:432)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:927)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.startup.Catalina.start(Catalina.java:772)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:345)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:476)
Mar 09, 2022 10:01:40 AM org.apache.catalina.core.StandardContext startInternal
SEVERE: One or more Filters failed to start. Full details will be found in the appropriate container log file
Mar 09, 2022 10:01:40 AM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/Struts2Starter] startup failed due to previous errors
Mar 09, 2022 10:01:40 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8081"]
Mar 09, 2022 10:01:40 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in [8729] milliseconds
问题已经解决了。ClassNotFoundException错误是由于没有将jar文件正确添加到Web部署程序集中。现在我已经阅读了它们，这个异常不再出现在控制台上。
另一个问题即将出现：没有为命名空间[/]和与上下文路径[/Struts2Starter]关联的操作名称[getTutorial]映射Action。
我必须在struts.xml文件中查看我的url操作映射。如果需要的话，我会把它作为一个新问题发布。