动态Web应用程序，Eclipse，JSF中的异常java.lang.NoClassDefFoundError [英] Exception java.lang.NoClassDefFoundError in Dynamic Web Application, Eclipse, JSF

问题描述

当我运行我的应用程序时，一切都可以，当我按下按钮，我正在重定向到另一个xhtml页面。然后eclipse控制台，直到我停止服务器显示：

when I'm running my appication everything is ok to moment when I press the button and I'm redirecting to another xhtml page. Then eclipse console until I stop server display:

SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/ChatAzure] threw exception [javax/servlet/jsp/jstl/core/Config] with root cause
java.lang.NoClassDefFoundError: javax/servlet/jsp/jstl/core/Config
    at com.sun.faces.application.view.JspViewHandlingStrategy.executePageToBuildView(JspViewHandlingStrategy.java:345)
    at com.sun.faces.application.view.JspViewHandlingStrategy.buildView(JspViewHandlingStrategy.java:154)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:100)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:928)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:539)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:298)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

我使用：
eclipse，jsf2-1-7，jstl-1.2.jar，Tomcat v0 0.7。
我不知道是什么问题，我需要帮助。

I use: eclipse, jsf2-1-7, jstl-1.2.jar, Tomcat v0.7. I don't know what's wrong, I need help.

推荐答案

上述类是JSTL的一部分。这通常由完整的Java EE容器提供，但Tomcat中不是作为准系统的JSP / Servlet容器提供的。您需要自己提供JSTL和Web应用程序。它最终被放置在webapp的运行时类路径中。

The mentioned class is part of JSTL. This is normally already provided by a full fledged Java EE container, but not in Tomcat as being a barebones JSP/Servlet container. You'd need to supply JSTL yourself along with the web application. It has ultimately to be placed in the webapp's runtime classpath.

您正确地提到了 jstl-1.2.jar （I假设这正是您在我们的JSTL维基页面中可以找到的那样），但这个问题表明它显然不是被放在正确的地方。您需要将其放在web项目的 / WEB-INF / lib 文件夹中。该文件夹由webapp的默认运行时类路径覆盖。没有更多的事情需要做。如果您曾经在项目的构建路径属性中轻松解决问题，您应该撤消所有这些尝试。

You correctly mentioned jstl-1.2.jar (I assume that it's exactly the one as you could find in our JSTL wiki page), but this problem indicates that it has apparently not been placed at the right place. You need to place it in /WEB-INF/lib folder of the web project. This folder is covered by webapp's default runtime classpath. Nothing more needs to be done. If you have ever fiddled in the project's Build Path properties in an attempt to solve it, you should undo all those attempts.

不相关的具体问题：为什么还在使用旧版JSP？自从JSF 2.0以来，已经被不再使用Facelets（XHTML）。确保您在学习JSF时阅读最新的JSF 2.x资源，而不是JSF 1.x资源。

Unrelated to the concrete problem: why are you still using legacy JSP? It has been deprecated and succeeded by Facelets (XHTML) since JSF 2.0. Make sure that you're reading up to date JSF 2.x resources and not JSF 1.x ones while learning JSF.

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