Question

我有HelloWorld servlet，并将类文件放置到webapps\ROOT\WEB-INF\classes中。在web.xml中添加一些行：

<servlet>
   <servlet-name>HelloWorld</servlet-name>
   <servlet-class>HelloWorld</servlet-class>
</servlet>

<servlet-mapping>
   <servlet-name>HelloWorld</servlet-name>
   <url-pattern>/HelloWorld</url-pattern>
</servlet-mapping>

网页运行正常。现在，我希望servlet写入我的日志文件。我已经用日志更新了我的servlet：

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;


public class HelloWorld extends HttpServlet {
    private static final Logger lg = LogManager.getLogger(HelloWorld.class);
    private String message;

    public void init() throws ServletException {
        lg.info("init");
        // Do required initialization
        message = "Hello World 1";
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        lg.info("doGet start");
        // Set response content type
        response.setContentType("text/html");

        // Actual logic goes here.
        PrintWriter out = response.getWriter();
        out.println("<h1>" + message + "</h1>");
    }

    public void destroy() {
        lg.info("destroy");
    }
}

我将log4j-core-2.11.2.jar，log4j-api-2.11.2.jar，log4j2.xml文件放在与我的类文件相同的文件夹中。 Web浏览器显示异常：

Type Exception Report

Message Error instantiating servlet class [HelloWorld]

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

javax.servlet.ServletException: Error instantiating servlet class [HelloWorld]
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:668)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:748)
Root Cause

java.lang.NoClassDefFoundError: org/apache/logging/log4j/LogManager
    HelloWorld.<clinit>(HelloWorld.java:9)
    sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:668)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:748)
Root Cause

java.lang.ClassNotFoundException: org.apache.logging.log4j.LogManager
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1343)
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1173)
    HelloWorld.<clinit>(HelloWorld.java:9)
    sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:668)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

我想原因是系统找不到log4j jar文件。我应该在哪里放置应用程序jar库？

TomCat中的应用程序jar库和配置文件位置

0 个答案: