Java log4j详细教程

package com.mucfc;
import org.apache.log4j.Logger;
/**
 *@author linbingwen
 *@2015年5月18日9:14:21
 */
public class Test {
 private static Logger logger = Logger.getLogger(Test.class); 
 /** 
 * @param args 
 */ 
 public static void main(String[] args) { 
 // System.out.println("This is println message."); 
 // 记录debug级别的信息 
 logger.debug("This is debug message."); 
 // 记录info级别的信息 
 logger.info("This is info message."); 
 // 记录error级别的信息 
 logger.error("This is error message."); 
 } 
}

<?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_3_0.xsd" 
 id="WebApp_ID" version="3.0"> 
 <display-name>LogLearning</display-name> 
 <servlet> 
 <servlet-name>Log4JTestServlet</servlet-name> 
 <servlet-class>com.mucfc.Log4JTestServlet</servlet-class> 
 </servlet> 
 <!--用来启动 log4jConfigLocation的servlet --> 
 <servlet> 
 <servlet-name>Log4JInitServlet</servlet-name> 
 <servlet-class>com.mucfc.Log4JInitServlet</servlet-class> 
 <init-param> 
 <param-name>log4j-properties-location</param-name> 
 <param-value>/WEB-INF/classes/log4j.properties</param-value> 
 </init-param> 
 <load-on-startup>1</load-on-startup> 
 </servlet> 
 <servlet-mapping> 
 <servlet-name>Log4JTestServlet</servlet-name> 
 <url-pattern>/test</url-pattern> 
 </servlet-mapping> 
</web-app>

Log4JInitServlet.java
package com.mucfc; 
import java.io.File; 
import java.io.IOException; 
import javax.servlet.ServletConfig; 
import javax.servlet.ServletContext; 
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 org.apache.log4j.BasicConfigurator; 
import org.apache.log4j.PropertyConfigurator; 
/** 
 * Servlet implementation class Log4JInitServlet 
 */ 
@WebServlet("/Log4JInitServlet") 
public class Log4JInitServlet extends HttpServlet { 
 private static final long serialVersionUID = 1L; 
 /** 
 * @see HttpServlet#HttpServlet() 
 */ 
 public Log4JInitServlet() { 
 super(); 
 // TODO Auto-generated constructor stub 
 } 
 /** 
 * @see Servlet#init(ServletConfig) 
 */ 
 public void init(ServletConfig config) throws ServletException { 
 System.out.println("Log4JInitServlet 正在初始化 log4j日志设置信息"); 
 String log4jLocation = config.getInitParameter("log4j-properties-location"); 
 ServletContext sc = config.getServletContext(); 
 if (log4jLocation == null) { 
 System.err.println("*** 没有 log4j-properties-location 初始化的文件, 所以使用 BasicConfigurator初始化"); 
 BasicConfigurator.configure(); 
 } else { 
 String webAppPath = sc.getRealPath("/"); 
 String log4jProp = webAppPath + log4jLocation; 
 File yoMamaYesThisSaysYoMama = new File(log4jProp); 
 if (yoMamaYesThisSaysYoMama.exists()) { 
 System.out.println("使用: " + log4jProp+"初始化日志设置信息"); 
 PropertyConfigurator.configure(log4jProp); 
 } else { 
 System.err.println("*** " + log4jProp + " 文件没有找到， 所以使用 BasicConfigurator初始化"); 
 BasicConfigurator.configure(); 
 } 
 } 
 super.init(config); 
 } 
 /** 
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
 */ 
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
 // TODO Auto-generated method stub 
 } 
 /** 
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
 */ 
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
 // TODO Auto-generated method stub 
 } 
}

package com.mucfc; 
import java.io.IOException; 
import javax.servlet.ServletConfig; 
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 org.apache.log4j.Logger; 
/** 
 * Servlet implementation class Log4JTestServlet 
 */ 
@WebServlet("/Log4JTestServlet") 
public class Log4JTestServlet extends HttpServlet { 
 private static final long serialVersionUID = 1L; 
 private static Logger logger = Logger.getLogger(Log4JTestServlet.class); 
 /** 
 * @see HttpServlet#HttpServlet() 
 */ 
 public Log4JTestServlet() { 
 super(); 
 // TODO Auto-generated constructor stub 
 } 
 /** 
 * @see Servlet#init(ServletConfig) 
 */ 
 public void init(ServletConfig config) throws ServletException { 
 // TODO Auto-generated method stub 
 } 
 /** 
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
 */ 
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
 // 记录debug级别的信息 
 logger.debug("This is debug message."); 
 // 记录info级别的信息 
 logger.info("This is info message."); 
 // 记录error级别的信息 
 logger.error("This is error message."); 
 } 
 /** 
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
 */ 
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
 doGet(request,response); 
 } 
}

<!-- 设置根目录 --> 
 <context-param> 
 <param-name>webAppRootKey</param-name> 
 <param-value>webapp.root</param-value> 
 </context-param> 
 <context-param> 
 <param-name>log4jConfigLocation</param-name> 
 <param-value>/WEB-INF/classes/log4j.properties</param-value> 
</context-param> 
<!-- 3000表示 开一条watchdog线程每60秒扫描一下配置文件的变化;这样便于日志存放位置的改变 --> 
<context-param> 
 <param-name>log4jRefreshInterval</param-name> 
 <param-value>3000</param-value> 
 </context-param> 
<listener> 
 <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class> 
</listener>

<?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_3_0.xsd" 
 id="WebApp_ID" version="3.0"> 
 <display-name>LogLearning</display-name> 
 <servlet> 
  <servlet-name>Log4JTestServlet</servlet-name> 
  <servlet-class>com.mucfc.Log4JTestServlet</servlet-class> 
 </servlet> 
 <!--用来启动 log4jConfigLocation的servlet --> 
<!--  <servlet> 
  <servlet-name>Log4JInitServlet</servlet-name> 
  <servlet-class>com.mucfc.Log4JInitServlet</servlet-class> 
  <init-param> 
   <param-name>log4j-properties-location</param-name> 
   <param-value>/WEB-INF/classes/log4j.properties</param-value> 
  </init-param> 
  <load-on-startup>1</load-on-startup> 
 </servlet>--> 
 <servlet-mapping> 
  <servlet-name>Log4JTestServlet</servlet-name> 
  <url-pattern>/test</url-pattern> 
 </servlet-mapping> 
  <!-- Spring 容器加载 --> 
 <listener> 
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> 
 </listener> 
 <context-param> 
  <param-name>contextConfigLocation</param-name> 
  <param-value>classpath:applicationContext.xml</param-value> 
 </context-param> 
 <!-- 设置根目录 --> 
 <context-param> 
  <param-name>webAppRootKey</param-name> 
  <param-value>webapp.root</param-value> 
 </context-param> 
 <context-param> 
  <param-name>log4jConfigLocation</param-name> 
  <param-value>/WEB-INF/classes/log4j.properties</param-value> 
 </context-param> 
 <!-- 3000表示 开一条watchdog线程每60秒扫描一下配置文件的变化;这样便于日志存放位置的改变 --> 
 <context-param> 
   <param-name>log4jRefreshInterval</param-name> 
   <param-value>3000</param-value> 
 </context-param> 
 <listener> 
  <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class> 
 </listener> 
</web-app>

<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" 
 xmlns:aop="http://www.springframework.org/schema/aop" 
 xsi:schemaLocation=" 
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context-3.2.xsd"> 
</beans>