我想做一个简单的项目来学习如何使用axis2的web服务。 所以我想做这个教程：https://www.youtube.com/watch?v=lgY0pLadraE 但是当我启动我的tomcat服务器时，我遇到了这个错误：
java.lang.NullPointerException
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:374)
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
at org.apache.axis2.transport.http.AxisAdminServlet.<clinit>(AxisAdminServlet.java:34)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.lang.Class.newInstance(Class.java:442)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:114)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1146)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1085)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5349)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5641)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
然后当我创建我的Web服务并在服务器中运行我的项目时，我得到第一页，其中有三个链接（服务，验证和管理）。当我点击服务链接时，我收到了这个错误：
type Rapport d''exception
message "Servlet.init()" pour la servlet AxisServlet a généré une exception
description Le serveur a rencontré une erreur interne qui l''a empêché de satisfaire la requête.
exception
javax.servlet.ServletException: "Servlet.init()" pour la servlet AxisServlet a généré une exception
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
导致mère
org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException))
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
导致mère
java.lang.ExceptionInInitializerError
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
导致mère
org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException))
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
导致mère
org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException)
org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:397)
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
导致mère
java.lang.NullPointerException
org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:374)
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
我该如何解决这个问题？这是我第一次制作网络服务