java.lang.NoClassDefFoundError：org / hibernate / MappingException

Question

啟動我的Apache Tomcat服務器時出現以下錯誤。 我已經將Struts與Hibernate框架集成在一起。

誰能告訴我這種例外的原因？

啟動服務器時會出現PFA異常日志？

Feb 11, 2014 10:46:09 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jre7\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre7/bin/client;C:/Program Files/Java/jre7/bin;C:/Program Files/Java/jre7/lib/i386;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\eclipse-standard-kepler-R-win32\eclipse;;.
Feb 11, 2014 10:46:09 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:StrutsOne' did not find a matching property.
Feb 11, 2014 10:46:09 AM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8080
Feb 11, 2014 10:46:09 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 766 ms
Feb 11, 2014 10:46:09 AM org.apache.catalina.core.StandardService start
INFO: Starting service Catalina
Feb 11, 2014 10:46:09 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.32
Feb 11, 2014 10:46:10 AM org.apache.struts.action.ActionServlet initChain
INFO: Loading chain catalog from jar:file:/C:/Users/Mohit/workspace/Struts/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/StrutsOne/WEB-INF/lib/struts-core-1.3.10.jar!/org/apache/struts/chain/chain-config.xml
Feb 11, 2014 10:46:10 AM org.apache.struts.action.ActionServlet init
SEVERE: Unable to initialize Struts ActionServlet due to an unexpected exception or error thrown, so marking the servlet as unavailable.  Most likely, this is due to an incorrect or missing library dependency.
java.lang.NoClassDefFoundError: org/hibernate/MappingException
    at java.lang.Class.getDeclaredConstructors0(Native Method)
    at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
    at java.lang.Class.getConstructor0(Unknown Source)
    at java.lang.Class.newInstance0(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at org.apache.struts.util.RequestUtils.applicationInstance(RequestUtils.java:172)
    at org.apache.struts.util.RequestUtils.applicationInstance(RequestUtils.java:147)
    at org.apache.struts.action.ActionServlet.initModulePlugIns(ActionServlet.java:842)
    at org.apache.struts.action.ActionServlet.init(ActionServlet.java:359)
    at javax.servlet.GenericServlet.init(GenericServlet.java:212)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:993)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4420)
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:4733)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
    at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
    at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
    at org.apache.catalina.core.StandardService.start(StandardService.java:525)
    at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: java.lang.ClassNotFoundException: org.hibernate.MappingException
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1680)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
    ... 27 more

Answer 1

如果您在Eclipse中工作，則應在Web項目類路徑中添加休眠jar並部署程序集。

通過右鍵單擊項目->屬性->部署程序集，然后添加jar。 或（如果jar位於WEB-INF / lib文件夾中），右鍵單擊項目->屬性-> Java構建路徑->選擇“庫”選項卡，然后添加庫，然后選擇weba bb庫

Answer 2

您在問這個異常的原因。

請查看日志告訴我們的內容，

“由於意外的異常或引發的錯誤而無法初始化Struts ActionServlet，因此將Servlet標記為不可用。這很可能是由於不正確或缺少庫依賴關系造成的”

啟動服務器時，通過拖放war文件或通過eclipse手動部署應用程序的應用程序，應用程序的第一個入口點是部署描述符，即web.xml 。 在這里，您已將Servlet定義為Struts Action Servlet，因此將嘗試初始化Struts ActionServlet。

現在，在您的struts-config.xml中，您可能會有類似的內容，

<struts-config>
....
    <plug-in className="com.example.MyHibernatePlugin">
        <set-property property="path" value="/hibernate.cfg.xml"/>
    </plug-in>
....
<struts-config>

com.example MyHibernatePlugin.java

import org.apache.struts.action.PlugIn;
public class HibernatePlugin implements PlugIn { ....{your code} }

話雖如此，現在您的日志正在嘗試說些什么，為什么它在嘗試初始化Struts Action Servlet時遇到了映射異常。

您的類路徑中必須具有與Struts和Hibernate相關的所有庫。 不要一次添加全部，一個一個地添加，看看它抱怨哪個罐子，然后添加直到它停止抱怨。