在WEB容器中配置自己log4j日志

对WEB应用程序来说,可以用一个特殊的servlet来初始化Log4j的配置

1.log4j初始化的servlet(Log4jInit.java)

 package com.sk.zhouf;

 import org.apache.log4j.PropertyConfigurator;
 import javax.servlet.http.HttpServlet;

 public class Log4jInit extends HttpServlet {
       public void init() {
               String prefix = getServletContext().getRealPath("/");
               String file = getInitParameter("log4j-init-file");
               if(file != null){
                          PropertyConfigurator.configure(prefix+file);
               }
       }
}

2.配置log4j的配置文件,我们用一个简单的配置文件(log4j.properties)

  log4j.rootLogger=ERROR, console
  log4j.logger.sk=DEBUG,console
  log4j.appender.console=org.apache.log4j.ConsoleAppender
  log4j.appender.console.layout=org.apache.log4j.SimpleLayout

3.配置web.xml

  <servlet>
           <servlet-name>Log4jInit</servlet-name>
           <servlet-class>com.sk.zhouf.Log4jInit</servlet-class>
           <init-param>
                    <param-name>log4j-init-file</param-name>
                    <param-value>WEB-INF/log4j.properties</param-value>
           </init-param>
           <load-on-startup>1</load-on-startup>
  </servlet>

说明一下:<load-on-startup>1</load-on-startup>必须的加上,当Tomcat服务器启动部署这个应用程序时,Log4jInit Servlet即被加载,从而完成对Log4j环境的配置

4.一个简单的servlet例子

package com.sk.zhouf;

import java.io.IOException;
import java.io.PrintWriter;
import org.apache.log4j.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class SimpleHello extends HttpServlet {
         static Logger logger = Logger.getLogger("sk");
         public void doGet(HttpServletRequest request, HttpServletResponse response)
                     throws ServletException, IOException {
                PrintWriter out = response.getWriter();
                logger.debug("hello benben");
                out.print("Hello  World!");
                out.close();
                logger.info("close");
       }
}

输出结果截图: