jakarta-ee - servlet : "FileNotFoundException: log4j.properties"中log4j的配置

Question

我已经开发了一个 servlet 应用程序并且想要配置 log4j，我已经通过使用下面的 log4j api 来配置 log4j 属性..

### direct log messages to stdout ###
#log4j.appender.stdout=org.apache.log4j.ConsoleAppender
#log4j.appender.stdout.Target=System.out
#log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
#log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1} - %m%n

### direct messages to file or.log ###
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=C:/logs/sdfghjkloiuyyttt.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1} - %m%n
log4j.appender.file.append=true

### set log levels - for more verbose logging change 'info' to 'debug' ##
log4j.rootCategory=ALL, file
log4j.logger.com.saral=debug
log4j.logger.org.eclipse=debug

应用程序的 web.xml 是..

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>FirstDemo</display-name>


  <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>/WEB-INF/log4j.properties</param-value>
</context-param>


  <servlet>
    <servlet-name>hello</servlet-name>
    <servlet-class>com.saral.MyServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>hello</servlet-name>
    <url-pattern>/helloServlet</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>home.html</welcome-file>
  </welcome-file-list>


  <listener>
  <listener-class>com.saral.SessionCounter</listener-class>
</listener>

</web-app>

我使用 Log4j 的主类是..

package com.saral;

import java.io.IOException;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class First
 */
//@WebServlet("/First")
public class MyServlet extends HttpServlet
{
    private static final long serialVersionUID = 1L;
    static final Logger logger = Logger.getLogger(MyServlet.class);


    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        PropertyConfigurator.configure("log4j.properties");
        logger.info("before---->");

        // TODO Auto-generated method stub
        String name=request.getParameter("txtName");
        response.setContentType("text/html");
        PrintWriter out=response.getWriter();
        out.println("Hello,"+name);
        out.println("<br> this output is generated by a simple servlet.");
        out.println("Total Number of users logged in--->"+request.getSession().getServletContext().getAttribute("sessionCount"));
        out.close();
        }}

但我得到以下异常..

log4j:ERROR Ignoring configuration file [log4j.properties].
log4j:ERROR Could not read configuration file [log4j.properties].
java.io.FileNotFoundException: log4j.properties (The system cannot find the file specified)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(Unknown Source)
    at java.io.FileInputStream.<init>(Unknown Source)
    at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:306)
    at org.apache.log4j.PropertyConfigurator.configure(PropertyConfigurator.java:324)
    at com.saral.MyServlet.doGet(MyServlet.java:29)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    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:225)
    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:927)
    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:999)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
log4j:ERROR Ignoring configuration file [log4j.properties].
log4j:ERROR Could not read configuration file [log4j.properties].

请告知如何克服...!!

Answer 1

据我所知，使用能力

<context-param>
    <param-name>log4jConfigLocation</param-name>
    <param-value>/WEB-INF/log4j.properties</param-value>
</context-param>

是 Spring 的重要组成部分 Log4jWebConfigurer ，除非你有类似的东西，否则不会使用它

<listener>
    <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
</listener>

在你的 web.xml 中。如果没有它，log4j 只会尝试从您的类路径中读取 log4j.properties(即，如果您将其放入 /WEB-INF/classes/log4j.properties，那么 log4j会自动拾取它，而不需要 spring 监听器(它还带有一个警告，除非 WAR 被您的容器自动分解，否则它不会工作)。