Log4j2 在WEB中的配置

時間 2019-11-11

標籤 log4j2 log web 配置欄目 Log4j 简体版

原文原文鏈接

首先先到http://logging.apache.org/log4j/2.x/download.html下載log4j 2.xhtml

如圖1：web的jar包java

如圖1所示，是在WEB項目中使用log4j2須要的jar包。在WEB項目中咱們須要把它拷貝到WEB-INF目錄的lib目錄下。web

在WEB項目中使用log4j2須要在web.xml文件中配置以下的監聽器和過濾器。apache

<listener>
                   <listener-class>org.apache.logging.log4j.web.Log4jServletContextListener</listener-class>
         </listener>
         <filter>
                   <filter-name>log4jServletFilter</filter-name>
                   <filter-class>org.apache.logging.log4j.web.Log4jServletFilter</filter-class>
         </filter>
         <filter-mapping>
                   <filter-name>log4jServletFilter</filter-name>
                   <url-pattern>/*</url-pattern>
                   <dispatcher>REQUEST</dispatcher>
                   <dispatcher>FORWARD</dispatcher>
                   <dispatcher>INCLUDE</dispatcher>
                   <dispatcher>ERROR</dispatcher>
         </filter-mapping>

下面經過一個例子來講明一下：tomcat

用eclipse新建一個Dynamic Web Project工程。而後建一個log4j2.jsp的文件內容以下：服務器

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>log4j2 web test</title>
</head>
<body>
<form action="LogServlet" method="post">
<input type="submit">
</form>
</body>
</html>

建一個Servlet類LogServlet類容以下（爲了更加清晰知道咱們使用了哪個日誌類，我把import也貼出來了）：app

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
 
/**
 * Servlet implementation class LogServlet
 */
public class LogServlet extends HttpServlet {
         private static final long serialVersionUID = 1L;
      
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LogServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
 
         /**
          * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
          */
         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         }
 
         /**
          * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
          */
         protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
                   Logger log = LogManager.getLogger();
                   log.info("log4j test");
                   log.debug("debug");
                   log.error("error");
         }
 
}

把log4j2的監聽器和過濾器加入web.xml中：web.xml的類容以下：eclipse

<?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"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         id="WebApp_ID" version="2.5">
         <display-name>invoicing</display-name>
         <welcome-file-list>
                   <welcome-file>index.jsp</welcome-file>
         </welcome-file-list>
         <!-- 配置log4j2 -->
         <listener>
                   <listener-class>org.apache.logging.log4j.web.Log4jServletContextListener</listener-class>
         </listener>
         <filter>
                   <filter-name>log4jServletFilter</filter-name>
                   <filter-class>org.apache.logging.log4j.web.Log4jServletFilter</filter-class>
         </filter>
         <filter-mapping>
                   <filter-name>log4jServletFilter</filter-name>
                   <url-pattern>/*</url-pattern>
                   <dispatcher>REQUEST</dispatcher>
                   <dispatcher>FORWARD</dispatcher>
                   <dispatcher>INCLUDE</dispatcher>
                   <dispatcher>ERROR</dispatcher>
         </filter-mapping>
         <filter>
                   <filter-name>encoding</filter-name>
                   <filter-class>org.wl.filter.EncodingFilter</filter-class>
         </filter>
         <filter-mapping>
                   <filter-name>encoding</filter-name>
                   <url-pattern>/*</url-pattern>
         </filter-mapping>
         <servlet>
                   <description></description>
                   <display-name>LogServlet</display-name>
                   <servlet-name>LogServlet</servlet-name>
                   <servlet-class>org.wl.app.login.LogServlet</servlet-class>
         </servlet>
         <servlet-mapping>
                   <servlet-name>LogServlet</servlet-name>
                   <url-pattern>/LogServlet</url-pattern>
         </servlet-mapping>
</web-app>

而後咱們能夠在tomcat服務器上運行程序，能夠發如今項目的根目錄下有logs文件夾下有一個app.log的日誌文件。能夠配置log4j2.xml更改。log4j2.xml配置文件要放在classpath下，通常放在src目錄下。關於log4j2的配置能夠參考：http://logging.apache.org/log4j/2.x/manual/customconfig.htmlwebapp

下面是log4j2.xml的配置,若是你使用的是eclipse你可能發現並無在項目根目錄中找到日誌文件，實際上是在項目所在的工做空間的\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps目錄下，例如個人項目工做空間是E:\web1,那麼實際的運行時的目錄在下面的目錄中，你能夠在相應的目錄中找到日誌文件。jsp

E:\web1\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps

<?xml version="1.0" encoding="UTF-8"?>   
<configuration status="error">   
  <appenders>   
    <Console name="Console" target="SYSTEM_OUT">   
      <ThresholdFilter level="trace" onMatch="ACCEPT" onMismatch="DENY"/>   
      <PatternLayout pattern="%d{HH:mm:ss.SSS} %-5level %class{36} %L %M - %msg%xEx%n"/>   
    </Console>   
    <File name="log" fileName="target/test.log" append="false">   
      <PatternLayout pattern="%d{HH:mm:ss.SSS} %-5level %class{36} %L %M - %msg%xEx%n"/>   
    </File>   
    <RollingFile name="RollingFile" fileName="${web:rootDir}/logs/app.log"   
                 filePattern="logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">   
      <PatternLayout pattern="%d{yyyy.MM.dd 'at' HH:mm:ss z} %-5level %class{36} %L %M - %msg%xEx%n"/>   
      <SizeBasedTriggeringPolicy size="20 MB" />   
    </RollingFile>   
  </appenders>   
  <loggers>   
    <root level="info">   
      <appender-ref ref="RollingFile"/>   
      <appender-ref ref="Console"/>
     <!--  <appender-ref ref="log" />   -->
    </root>   
  </loggers>   
</configuration>

在上面的配置中注意其中${web:rootDir}表明項目的根目錄，這樣配置當咱們項目部署到其餘地方的時候就不用去更改目錄了。