1、引入jar包

2、在web.xml配置檔案中做如下配置

 <servlet>
    <servlet-name>Log4jInitServlte</servlet-name>
    <servlet-class>com.zdys.Servlte.Log4jInitServlte</servlet-class>
     <init-param>  
	<param-name>log4j</param-name>  
	<param-value>WEB-INF/log4j.properties</param-value><!--log4j配置檔案路徑-->  
	</init-param>  
	<load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>Log4jInitServlte</servlet-name>
    <url-pattern>/Log4jInitServlte</url-pattern>
  </servlet-mapping>

3.在web-INF下建立log4j.properties配置檔案 配置檔案內容如下

1. 其語法為：  
2.     log4j.rootLogger = [ level ] , appenderName1, appenderName2, …  
3. level: 是日誌記錄的優先順序，分為OFF、FATAL、ERROR、WARN、INFO、DEBUG、ALL或  
4. 者您定義的級別。Log4j建議只使用四個級別，優 先級從高到低分別是ERROR、WARN、INFO、DEBUG。通過在這裡定義的級別，您可以控制到應用程式中相應級別的日誌資訊的開關。比如在這裡定 義了INFO級別，則應用程式中所有DEBUG級別的日誌資訊將不被打印出來。  
5. appenderName: 就是指定日誌資訊輸出到哪個地方。您可以同時指定多個輸出目的地。  
6.         例如：log4j.rootLogger＝info,A1,B2,C3 

Appender 為日誌輸出目的地，Log4j提供的appender有以下幾種：

org.apache.log4j.ConsoleAppender（控制檯），
org.apache.log4j.FileAppender（檔案），
org.apache.log4j.DailyRollingFileAppender（每天產生一個日誌檔案），
org.apache.log4j.RollingFileAppender（檔案大小到達指定尺寸的時候產生一個新的檔案），

org.apache.log4j.WriterAppender（將日誌資訊以流格式傳送到任意指定的地方）

log4j.rootLogger=DEBUG,A1,A2,A3,A4,A6
 
###  system.out  ###
log4j.appender.A2 =org.apache.log4j.ConsoleAppender
log4j.appender.A2.Threshold=DEBUG
log4j.appender.A2.Target=System.out
log4j.appender.A2.encoding=UTF-8
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=[%x] [%-d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n
 
### file debug ###
log4j.appender.A1 = org.apache.log4j.DailyRollingFileAppender
log4j.appender.A1.File = ../logs/DServerDebug.log
log4j.appender.A1.DatePattern='.'yyyy-MM-dd
###log4j.appender.A1.MaxFileSize=100MB
log4j.appender.A1.encoding=UTF-8
log4j.appender.A1.Append = true
log4j.appender.A1.Threshold = DEBUG
log4j.appender.A1.layout = org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=[%x] [%-d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n
 
### file INFO ###
log4j.appender.A3 = org.apache.log4j.DailyRollingFileAppender
log4j.appender.A3.File = ../logs/DServerINFO.log
log4j.appender.A3.DatePattern='.'yyyy-MM-dd
###log4j.appender.A3.MaxFileSize=10MB
log4j.appender.A3.encoding=UTF-8
log4j.appender.A3.Append = true
log4j.appender.A3.Threshold = INFO
log4j.appender.A3.layout = org.apache.log4j.PatternLayout
log4j.appender.A3.layout.ConversionPattern=[%x] [%-d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n


### file WARN ###
log4j.appender.A3 = org.apache.log4j.DailyRollingFileAppender
log4j.appender.A3.File = ../logs/DServerWARN.log
log4j.appender.A3.DatePattern='.'yyyy-MM-dd
###log4j.appender.A3.MaxFileSize=10MB
log4j.appender.A3.encoding=UTF-8
log4j.appender.A3.Append = true
log4j.appender.A3.Threshold = WARN
log4j.appender.A3.layout = org.apache.log4j.PatternLayout
log4j.appender.A3.layout.ConversionPattern=[%x] [%-d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n
  
 
### file ERROR ###
log4j.appender.A4 = org.apache.log4j.DailyRollingFileAppender
log4j.appender.A4.File = ../logs/DServerERROR.log
log4j.appender.A4.DatePattern='.'yyyy-MM-dd
###log4j.appender.A4.MaxFileSize=100MB
log4j.appender.A4.encoding=UTF-8
log4j.appender.A4.Append = true
log4j.appender.A4.Threshold = ERROR
log4j.appender.A4.layout = org.apache.log4j.PatternLayout
log4j.appender.A4.layout.ConversionPattern=[%x] [%-d{yyyy-MM-dd HH:mm:ss}] [%p] %m%n


# everyday    
log4j.appender.A6=org.apache.log4j.DaliyRollingFileAppender    
log4j.appender.A6.File=../logs/DServerEveryDay.log     
log4j.appender.A6.DatePattern=yyyyMMdd-HH'.log'     
log4j.appender.A6.layout=org.apache.log4j.PatternLayout     
log4j.appender.A6.layout.ConversionPattern=%d{yyyy-MM-dd HH\:mm\:ss} [INFO] %m%n 

4、建立Log4jInitServlte類

package com.zdys.Servlte;

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.log4j.PropertyConfigurator;


public class Log4jInitServlte  extends HttpServlet{

	/**
	 * 
	 */
	private static final long serialVersionUID = -865926669490098235L;
	
	public Log4jInitServlte() {
		super();
	}
	
	/**
	 * 初始化Servlet
	 */
	public void init() throws ServletException {
		

Logger logger = Logger.getLogger(Log4jInitServlte.class);

String path = getServletContext().getRealPath("/"); String log4jpropfile = path + getInitParameter("log4j"); System.out.println("日誌的配置檔案路徑為："+log4jpropfile); if(log4jpropfile != null) { PropertyConfigurator.configure(log4jpropfile); //載入配置檔案 System.out.println("日誌的配置檔案讀取成功"); }

logger.fatal("這是一條從TestServlet產生的fatal資訊！");
logger.error("這是一條從TestServlet產生的error資訊！");
logger.warn("這是一條從TestServlet產生的warn資訊！");
logger.debug("這是一條從TestServlet產生的debug資訊！");
logger.info("這是一條從TestServlet產生的info資訊！");

	}
	
	/**
	 * doGet
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
		
	}
	
	/**
	 * doPost
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");//設定字元編碼
		response.setContentType("text/html;charset=utf-8");
		
			
		
	}
	
	/**
	 * 銷燬Servlet
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		
	}

}