log4j的配制及测试程序

1，写个初始化的SERVLET：
package net.welovetennis.util.log;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.log4j.*;
/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2004</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */
public class Log4jInit extends HttpServlet {
    //Initialize global variables
    public void init() throws ServletException {
        String prefix =  getServletContext().getRealPath("/");
        String file = getInitParameter("log4j");
// if the log4j-init-file is not set, then no point in trying
        System.out.println("................log4j start");
        if(file != null) {
            PropertyConfigurator.configure(prefix+file);
        }
    }
    //Process the HTTP Get request
    public void doGet(HttpServletRequest request, HttpServletResponse response) {
    }
    //Clean up resources
    public void destroy() {
    }
}

2，修改WEB。XML：
<servlet>
    <servlet-name>log4jinit</servlet-name>
    <servlet-class>net.welovetennis.util.log.Log4jInit</servlet-class>
    <init-param>
 <param-name>log4j</param-name>
 <param-value>WEB-INF/log4j.properties</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
3，在WEB-INF下放配制文件log4j.properties，并指定输出路径：
log4j.rootLogger=INFO, A1 , R
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=c:/project/david/racquet/logs/log4j.log
log4j.appender.R.MaxFileSize=100KB
log4j.appender.R.MaxBackupIndex=1
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n