Java/Servlets/Log

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Another logger servlet

   <source lang="java">

//Log4j from Apache is required import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator; import javax.servlet.*; import javax.servlet.http.*; public class LoggerServlet2 extends HttpServlet { 

 private Logger log = null;
 public void init() {
   log = Logger.getLogger(LoggerServlet2.class);
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //display a DEBUG level message
   log.debug("Sending a DEBUG message from logger2");
   //display an INFO level message
   log.info("Sending an INFO message from logger2");
   //better display something
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head><title>Servlet logging</title></head><body>");
out.println("

Hello from LoggerServlet

"); 
   out.println("Your logger name is: " + log.getName() + "
");
   out.println("Your logger parent is: " + log.getParent().getName()
       + "
");
   out.println("</body></html>");
   out.close();
 } //end doGet
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   doGet(request, response);
 }

} 


 </source>



Context log

   <source lang="java">

import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ContextLog extends HttpServlet { 

 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   String yourMessage = request.getParameter("mine");
   //Call the two ServletContext.log methods
   //the javax.servlet.GenericServlet.getServletContext method
   ServletContext context = getServletContext();
   if (yourMessage == null || yourMessage.equals(""))
     //log version with Throwable parameter
     context.log("No message received:", new IllegalStateException(
         "Missing parameter"));
   else
     context.log("Here is the visitor"s message: " + yourMessage);
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   //logging servlets probably want to display more HTML; this is "lazy
   // HTML"
   out.println("<html><head><title>ServletContext logging</title></head><body>");
out.println("

Messages sent

"); 
   out.println("</body></html>");
 } //end doGet

} 


 </source>



Context logger

   <source lang="java">

//Log4j from Apache is required import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator; import javax.servlet.*; import javax.servlet.http.*; public class ContextLogger implements ServletContextListener { 

 private Logger log;
 public ContextLogger() {
 }
 public void contextDestroyed(ServletContextEvent sce) {
   String name = sce.getServletContext().getServletContextName();
   //log request of the INFO level
   log.info("ServletContext shut down: " + (name == null ? "" : name));
 }
 public void contextInitialized(ServletContextEvent sce) {
   ServletContext context = sce.getServletContext();
   String realPath = context.getRealPath("/");
   String fileSep = System.getProperty("file.separator");
   if (realPath != null && (!realPath.endsWith(fileSep)))
     realPath = realPath + fileSep;
   //Initialize logger here:
   PropertyConfigurator.configure(realPath + "WEB-INF/classes/"
       + context.getInitParameter("logger-config"));
   log = Logger.getLogger(ContextLogger.class);
   String name = context.getServletContextName();
   //log request about servlet context being initialized
   log.info("ServletContext ready: " + (name == null ? "" : name));
 }

} 


 </source>



Log Filter

   <source lang="java">

//Log4j from Apache is required import javax.servlet.*; import javax.servlet.http.*; import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator; public class LogFilter implements Filter { 

 private FilterConfig config;
 private Logger log;
 /** Creates new RequestFilter */
 public LogFilter() {
 }
 public void init(FilterConfig filterConfig) throws ServletException {
   this.config = filterConfig;
   //load the configuration for this application"s loggers using the
   // servletLog.properties file
   PropertyConfigurator.configure(config.getServletContext().getRealPath(
       "/")
       + "WEB-INF/classes/servletLog.properties");
   log = Logger.getLogger(LogFilter.class);
   log.info("Logger instantiated in " + getClass().getName());
 }
 public void doFilter(ServletRequest request, ServletResponse response,
     FilterChain chain) throws java.io.IOException, ServletException {
   HttpServletRequest req = null;
   String id = config.getInitParameter("log-id");
   if (id == null)
     id = "unknown";
   if (log != null && (request instanceof HttpServletRequest)) {
     req = (HttpServletRequest) request;
     log.info("Log id:" + id + ": Request received from: "
         + req.getRemoteHost() + " for " + req.getRequestURL());
   }
   chain.doFilter(request, response);
 }// doFilter
 public void destroy() {
   /*
    * called before the Filter instance is removed from service by the web
    * container
    */
   log = null;
 }

} 


 </source>



Logger new config

   <source lang="java">

//Log4j from Apache is required import org.apache.log4j.Logger; import javax.servlet.*; import javax.servlet.http.*; public class LoggerNewConfig extends HttpServlet { 

 private Logger log = null;
 public void init() {
   log = Logger.getLogger(LoggerNewConfig.class);
   log.info("LoggerNewConfig started.");
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //display a DEBUG level message
   log.debug("Sending a DEBUG message");
   // display an INFO level message
   log.info("Sending an INFO message");
   //better display some HTML
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head><title>Servlet logging</title></head><body>");
   out.println
("

Hello from a Logger with its own configuration in the log4j.properties file

"); 
   out.println("Your logger name is: " + log.getName() + "
");
   out.println("Your logger parent is: " + log.getParent().getName()
       + "
");
   out.println("</body></html>");
   out.close();
 } //end doGet
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   doGet(request, response);
 }

} 


 </source>



Logger Servlet

   <source lang="java">

//Log4j from Apache is required import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator; import javax.servlet.*; import javax.servlet.http.*; public class LoggerServlet extends HttpServlet { 

 private Logger log = null;
 public void init() {
   String realPath = getServletContext().getRealPath("/");
   String fileSep = System.getProperty("file.separator");
   if (realPath != null && (!realPath.endsWith(fileSep)))
     realPath = realPath + fileSep;
   System.out.println(realPath);
   //load the configuration for this application"s loggers using the
   // servletLog.properties file
   PropertyConfigurator.configure(realPath
       + "WEB-INF/classes/servletLog.properties");
   //create the logger for this servlet class
   //it will use the configuration for the logger com.jexp.LoggerServlet
   //or inherit from the logger com.jexp if one exists, and so on
   log = Logger.getLogger(LoggerServlet.class);
   log.info("LoggerServlet started.");
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //display a DEBUG level message
   log.debug("Sending a DEBUG message");
   //display an INFO level message
   log.info("Sending an INFO message");
   //better display something
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head><title>Servlet logging</title></head><body>");
out.println("

Hello from LoggerServlet

"); 
   out.println("Your logger name is: " + log.getName() + "
");
   out.println("Your logger parent is: " + log.getParent().getName()
       + "
");
   out.println("</body></html>");
   out.close();
 } //end doGet
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   doGet(request, response);
 }

} 


 </source>



LoggerSkel for Servlet

   <source lang="java">

//Log4j from Apache is required

import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator; import javax.servlet.*; import javax.servlet.http.*; public class LoggerSkel extends HttpServlet { 

 private Logger log;
 public void init() {
   PropertyConfigurator.configure(getServletContext().getRealPath("/")
       + "WEB-INF/classes/servletLog.properties");
   log = Logger.getLogger(LoggerSkel.class);
   log.debug("Instance created of: " + getClass().getName());
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //do logging here if necessary
 } //end doGet

} 


 </source>



Logger without configure file

   <source lang="java">

//Log4j from Apache is required import org.apache.log4j.Logger; import org.apache.log4j.BasicConfigurator; import javax.servlet.*; import javax.servlet.http.*; public class LoggerNconfig extends HttpServlet { 

 private Logger log = null;
 public void init() {
   log = Logger.getRootLogger();
   BasicConfigurator.configure();
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //display a DEBUG level message
   log.debug("Sending a DEBUG message");
   // display an INFO level message
   log.info("Sending an INFO message");
   //better display some HTML
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head><title>Servlet logging</title></head><body>");
out.println("

Hello from a Logger with no Config file

"); 
   out.println("Your logger name is: " + log.getName() + "
");
   out.println("Your logger parent is: " + log.getParent().getName()
       + "
");
   out.println("</body></html>");
 } //end doGet
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   doGet(request, response);
 }

} 


 </source>



Logging Filter

   <source lang="java">

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public final class LoggingFilter implements Filter { 

 private FilterConfig filterConfig = null;
 public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain)
   throws IOException, ServletException 
 {
   long start = System.currentTimeMillis();
   String address =  request.getRemoteAddr();
   String file = ((HttpServletRequest) request).getRequestURI();
       
   chain.doFilter(request, response);
   filterConfig.getServletContext().log(
       "User access! " +      
       " User IP: " + address +      
       " Resource: " + file + 
       " Milliseconds used: " + (System.currentTimeMillis() - start) 
   );
 }
 public void destroy() { }
 public void init(FilterConfig filterConfig) {
   this.filterConfig = filterConfig;
 }

} 


 </source>



Log in ServletContext

   <source lang="java">

// web.xml /* <?xml version="1.0" encoding="ISO-8859-1"?> <web-app xmlns="http://java.sun.ru/xml/ns/j2ee" 

        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:schemaLocation="http://java.sun.ru/xml/ns/j2ee
        http://java.sun.ru/xml/ns/j2ee/web-app_2_4.xsd" version="2.4">
 <servlet>
   <servlet-name>LoggingServlet</servlet-name>
   <servlet-class>LoggingServlet</servlet-class>
 </servlet>
 <servlet-mapping>
   <servlet-name>LoggingServlet</servlet-name>
   <url-pattern>/loggingServlet</url-pattern>
 </servlet-mapping>

</web-app>

  • /

import java.io.IOException; import javax.servlet.ServletConfig; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LoggingServlet extends HttpServlet { 

 private ServletContext context;
 public void init(ServletConfig config) throws ServletException {
   super.init(config);
   context = getServletContext();
   context.log("Init has been invoked");
 }
 public void doGet(HttpServletRequest req, HttpServletResponse res)
     throws IOException {
   ServletOutputStream out = res.getOutputStream();
   context.log("doGet has now been invoked");
   res.setContentType("text/html");
   out.println("<html><head><title>Logging Servlet</title></head>");
   out.println("<body>Visit the <tomcat-home>\\logs and open the xx file to see the log entries");
   out.println("</body></html>");
 }

} 


 </source>



Servlet Logging

   <source lang="java">

package net.firstpartners.nounit.utility; /** 

* Title:        NoUnit - Identify Classes that are not being unit Tested
*
* Copyright (C) 2001  Paul Browne , FirstPartners.net
*
*
* This program is free software; you can redistribute it and/or 
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*
* @author Paul Browne
* @version 0.6
*/

import java.io.*; import javax.servlet.*;

/** 

* stores log of system output and system errors
* If Servlet , writes to Servlet Log File.
* If non-Servlet , writes to Output Files Specified in parameters.

* Class is mainly static , to allow ease of use (one one log file per system!!) ,
* but has a non-static constructor (for use by servlets - so reference to servlet
* log file can be set.
*/

public class Logging { 

 //Class Level Variables
 static String logFileName;       // both package level to enable testing
 static String errorLogFileName;
 static FileWriter logWriter;
 static FileWriter errorWriter;
 static boolean doLogging=false;   //default no logging unless file says otherwise
 //For use in Servlet Context Logging
 static ServletContext innerContext;

 /**
  * Constructor for Logging from Servlet
  * @param inServletContext used to get access to the Servlet log files
  * @exception IOException if it can"t create log files
  */
  public Logging (ServletContext inServletContext) throws IOException {
   //Store incoming Context + Set Logging Flag
   this.innerContext= inServletContext;
   //Set logging flag
   doLogging=true;
   
 }

 /**
  * do Setup
  * @exception IOException if it can"t create log files
  */
 private static void setup () {
   try {
     //Check if setup required - ie nothing has been setup before
     if (((logFileName==null)&&(errorLogFileName==null))||(innerContext==null))
     {
       //Set logging flag
       
         doLogging=true;
         //Get logging parameters
         logFileName= "LogFile.txt";
         errorLogFileName = "ErrorLogFile.txt";
         //Create the files
         logWriter = new FileWriter(logFileName,true); //append data
         errorWriter = new FileWriter(errorLogFileName,true); //append
       
     }
   } catch (java.io.IOException ie) {
     //do nothing - exists to keep method signature simple
     //will show up as NullPointerException later
   }
 }
 /**
  * Print log of system output
  * @param sysOut
  */
 public static void printOutput(Object sysOut){
   //setup (if required)
   setup();
   //skip out asap if logging is turned off
   if (!doLogging) {return; }

   //Check for Servlet Logging
   if (innerContext!=null) {
     doServletLog(sysOut);
   } else {
     //do file logging
     try {
       if (sysOut instanceof Exception) {
         logWriter.write(((Exception)sysOut).toString());
         logWriter.flush();
       }
       else {
         logWriter.write(sysOut.toString());
         logWriter.flush();
       }
     } catch (java.io.IOException ioe) {
       //do nothing - let app continue
     }
   }
 }
 /**
  * Print log of system errors
  * This method catches java.io.IOExceptions internally , so as to give a
  * similar method signature to System.out.println. Also should we stop system
  * if logging (and only logging) fails?
  * @param sysErr
  */
 public static void printError(Object sysErr){
   //setup (if required)
   setup();
   //skip out asap if logging is turned off
   if (!doLogging) {return; }
   //Check for Servlet Logging
   if (innerContext!=null) {
     doServletLog(sysErr);
   } else {
     //do file logging
     try {
       if (sysErr instanceof Exception) {
         logWriter.write(((Exception)sysErr).toString());
         logWriter.flush();
       }
       else {
         logWriter.write(sysErr.toString());
         logWriter.flush();
       }
     } catch (java.io.IOException ioe) {
       //do nothing - let app continue
     }
   }
 }
 /**
  * private method for handling logging to Servlets
  * @param inObject to Log
  */
 private static void doServletLog (Object inObject) {
   if(inObject instanceof Throwable) {
     //Log as Exception
     innerContext.log("",(Throwable)inObject);
   } else {
     //Log as Normal String
     innerContext.log(inObject.toString());
   }

 }

 /**
  * Prints debug message to system log file.
  * Catches java.io.IOExceptions internally, so as to give a
  * similar method signature to System.out.println.
  *
  * @param object Object containing information to display
  */
 public static void debug(Object object){
   setup();
   if (doLogging) {
     if (innerContext==null) {
       // log debug message to file
       try {
         try {
           logWriter.write(((Exception)object).toString());
         }
         catch (ClassCastException e) {
           logWriter.write(object.toString());
         }
         logWriter.flush();
       } catch (IOException e) {
         //do nothing - let app continue
       }
     } else {
       doServletLog(object);
     }
   }
 }

} 

 </source>



Servlet: Root logger

   <source lang="java">

//Log4j from Apache is required import org.apache.log4j.Logger; import javax.servlet.*; import javax.servlet.http.*; public class LoggerWconfig extends HttpServlet { 

 private Logger log = null;
 public void init() {
   log = Logger.getRootLogger();
   log.info("LoggerWconfig started.");
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //display a DEBUG level message
   log.debug("Sending a DEBUG message");
   // display an INFO level message
   log.info("Sending an INFO message");
   //better display some HTML
   response.setContentType("text/html");
   java.io.PrintWriter out = response.getWriter();
   out.println("<html><head><title>Servlet logging</title></head><body>");
out.println("

Hello from a Logger with a log4j.properties file

"); 
   out.println("Your logger name is: " + log.getName() + "
");
   out.println("</body></html>");
 }
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   doGet(request, response);
 }

} 


 </source>



Servlets Logging Filter Demo

Источник — «http://jexp.ru/index.php?title=Java/Servlets/Log&oldid=6297»