Myeclipse部署Web Project时如何输出日志

    去官网下log4j-1.2.16.jar放在web项目的 WebRoot/WEB-INF/lib目录下， 然后再在MyEclipse右击属性里，添加到项目里，可能不添加也行。

     建一个 log4j.properties文件，放在WebRoot/WEB-INF/classes目录下，内容可以参考如下：

     log4j.rootCategory=INFO, stdout , R log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=[QC] %p [%t] %C.%M(%L) | %m%n log4j.appender.R=org.apache.log4j.DailyRollingFileAppender log4j.appender.R.File=dataservice.log log4j.appender.R.layout=org.apache.log4j.PatternLayout log4j.appender.R.layout.ConversionPattern=%d-[TS] %p %t %c - %m%n log4j.logger.com.neusoft=DEBUG log4j.logger.com.opensymphony.oscache=ERROR log4j.logger.net.sf.navigator=ERROR log4j.logger.org.apache.commons=ERROR log4j.logger.org.apache.struts=WARN log4j.logger.org.displaytag=ERROR log4j.logger.org.springframework=DEBUG log4j.logger.com.ibatis.db=WARN log4j.logger.org.apache.velocity=FATAL log4j.logger.com.canoo.webtest=WARN log4j.logger.org.hibernate.ps.PreparedStatementCache=WARN log4j.logger.org.hibernate=DEBUG log4j.logger.org.logicalcobwebs=WARN

 

     在web.xml中，添加上：

     <servlet> <servlet-name>j2eelog4jdemo</servlet-name><servlet-class>lab.iel.logs.J2eeLog4jDemo</servlet-class><init-param> <param-name>log4j</param-name><param-value>log4j.properties</param-value> </init-param><load-on-startup>1</load-on-startup> </servlet>  

 

    里面所提到的这个所谓的类 lab.iel.logs.J2eeLog4jDemo ，它内容如下：

    package lab.iel.logs;import java.io.IOException; import java.io.PrintWriter; 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 J2eeLog4jDemo extends HttpServlet { public void destroy() { super.destroy(); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } public void init() throws ServletException { //通过web.xml来动态取得配置文件 String prefix = getServletContext().getRealPath("/"); String file = getInitParameter("log4j"); //如果没有给出相应的配置文件，则不进行初始化 if(file != null) { PropertyConfigurator.configure(prefix+file); } } }

 

    建一个LogHelper类，专门用于处理输出日志，代码如下：

    import org.apache.log4j.*;public class LogHelper {private static Logger logger = null; private static void init(){logger = Logger.getLogger(lab.iel.logs.LogHelper.class);}public static Logger getLogger(){if(null ==logger){init();}return logger;}}

   

    调用 ：

      在jsp页面中

      <%@ page language="java" import="lab.iel.logs.LogHelper"%>

      然后写 LogHelper.getLogger().info("sth");

      就可以输出了

 

 

    如此，部署以后它就可以向，比如tomcat的文件夹里，写日志了。