log4j1.2.17使用

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网上找了一些资料没看明白，还是找到了一本书，书里有这一章，一步步敲下来。明白了。

PART 1 WEB应用里使用log4j

一、log4j1.2.17下载地址点击打开链接

二、myeclipse中新建WEB项目log4jtest, 并修改web.xml为：

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  <display-name></display-name>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list>  <servlet>      <servlet-name>log4j config file</servlet-name>      <servlet-class>sse.log4j.Log4jInitServlet</servlet-class>      <init-param>          <param-name>configfile</param-name>          <param-value>/WEB-INF/log4jconfig.properties</param-value>      </init-param>      <load-on-startup>1</load-on-startup>  </servlet></web-app>

三、新建/WEB-INF/log4jconfig.properties为：

log4j.rootLogger = DEBUG,filelog4j.logger.log4jTestLogger=WARN,console,filelog4j.appender.console=org.apache.log4j.ConsoleAppenderlog4j.appender.console.layout=org.apache.log4j.PatternLayoutlog4j.appender.console.layout.ConversionPattern=%d{yyyy-MM-dd  HH:mm:ss,SSS}  [%c]-[%p]%m%nlog4j.appender.file=org.apache.log4j.RollingFileAppenderlog4j.appender.file.File=C:/Program Files/Apache Software Foundation/Tomcat 6.0/webapps/log4jtest/WEB-INF/log.htmllog4j.appender.file.MaxFileSize=500KBlog4j.appender.file.MaxBackupIndex=1log4j.appender.file.layout=org.apache.log4j.HTMLLayout

四、新建sse.log4j.Log4jInitServlet类为：

package sse.log4j;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import org.apache.log4j.PropertyConfigurator;public class Log4jInitServlet extends HttpServlet {@Overridepublic void init() throws ServletException {// TODO Auto-generated method stubsuper.init();String path = getServletContext().getRealPath("/");String configfile = path + getInitParameter("configfile");PropertyConfigurator.configure(configfile);}}

五、新建空文件/WEB-INF/log.html

整个包结构图如下：

六、新建log4japp.jsp,内容如下：

<%@ page language="java" import="org.apache.log4j.Logger" pageEncoding="GB2312"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>        <title>log4j application</title>    <meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>  <body bgcolor="#FFFFFF"><%Logger rootlogger = Logger.getRootLogger();Logger log4jlogger = Logger.getLogger("log4jTestLogger");out.println("rootlogger's LEVEL is "+rootlogger.getLevel()+"<p>");out.println("log4jlogger's LEVEL is "+log4jlogger.getLevel()+"<p>");log4jlogger.debug("This is DEBUG info from "+log4jlogger.getName());log4jlogger.info("This is INFO info from "+log4jlogger.getName());log4jlogger.warn("This is WARN info from "+log4jlogger.getName());log4jlogger.error("This is ERROR info from "+log4jlogger.getName());log4jlogger.fatal("This is FATAL info from "+log4jlogger.getName());out.println("\nlog info has been printed!"); %>  </body></html>

七、启动tomcat，在浏览器中打入URL运行log4japp.jsp，可看到Console的部分输出（原因见参考资料）。

用浏览器打开log.html结果：

PART 2 普通java类里使用log4j

package Test;import org.apache.log4j.Logger;import org.apache.log4j.PropertyConfigurator;public class Test {     /*      * 步骤：      * 一、下载log4j.jar包,并导入      * 二、配置log4j.properties文件      */     private Logger log = Logger.getLogger(Test.class);     public Test() {         //log4jconfig.properties文件和当前运行的class放在同一目录下         String connectdir=Test.class.getResource("log4jconfig.properties").getPath();         PropertyConfigurator.configure(connectdir);         System.out.println(connectdir);     }     public void testprint() {         log.debug("debug test");         log.info("info test");         log.warn("warn test");         log.error("error test");     }     public static void main(String[] args) {         Test test = new Test();         test.testprint();     }}

log4j参考资料：

参考一

参考二

参考三