slf4j-api-1.7.5 Log Print Experiment

The following passage from: Baidu Encyclopedia
If you are developing a class library or embedded component, you should consider using SLF4J because it is not possible to affect which log system the end user chooses. On the other hand, if it is a simple or standalone application that determines that there is only one log system, then there is no need to use SLF4J. Assuming that you're going to sell your log4j products to users who require JDK 1.4 logging, it's definitely not an easy task to face thousands of changes to log4j calls. But if you start with slf4j, then this conversion will be a very easy thing to do.

Today to test the use of slf4j and its charm.

In general, the Java project is now a Web project, so our pilot project uses Web project testing.

1. Create a new Web project Slf4jdemo

2. Referencing the jar package

It is important to note that the slf4j corresponds to the log4j version, the person you can also choose other log system.

Log4j-1.2.12.jar

Servlet2.5-jsp2.1-api.jar

Slf4j-api-1.7.5.jar

Slf4j-log4j12-1.7.5.jar

3. Add the log4j configuration file log4j.properties

Here you need to explain that the default path of the log4j itself is under the/web-inf/classes/directory, so don't put it in the wrong place.

#log4j logger fatal=0 error=3 warn=4 info=6 debug=7#log4j.rootlogger = DEBUG, A1log4j.rootlogger = off### Direct Log Messa Ges to stdout # # #log4j. appender.stdout = Org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.Target = System.outlog4j.appender.stdout.layout = Org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern =%d{absolute}%5p%c{1}:%l-%m% Nlog4j.logger.org =error, a1log4j.logger.net = ERROR, A1log4j.logger.com.qisentech = DEBUG, a1log4j.appender.a1 = Org.apache.log4j.RollingFileAppenderlog4j.appender.a1.File = ${rootpath}/ Webplus.loglog4j.appender.a1.MaxFileSize = 10000kblog4j.appender.a1.maxbackupindex = 10log4j.appender.a1.layout = Org.apache.log4j.PatternLayoutlog4j.appender.a1.layout.ConversionPattern =%d [%t] (%f:%l)%c%-5p-%m%n# Log4j.rootlogger=warn, stdout#log4j.appender.stdout=org.apache.log4j.consoleappender# log4j.appender.stdout.layout=org.apache.log4j.patternlayout#log4j.appender.stdout.layout.conversionpattern=%d% p [%c]-%m%n

Look carefully at the configuration information, you can see a ${rootpath}, select we will initialize this variable.

4. Create a new initialization servlet

/* File name: Com.qisentech.slf4j.demo.WebplusContextStart.java * Date Created: 2013-8-23 11:20:48 * Created by: Qsyang */package com. Qisentech.slf4j.demo;import Javax.servlet.servletexception;import javax.servlet.http.httpservlet;/** * <p> Title: </p> * * <p>description: </p> * * @author Qsyang * @version 1.0 */public Class Webpluscontextstar T extends HttpServlet {    @Override public    void Init () throws Servletexception {        System.setproperty (" Log4j.configuration "," log4j.properties ");        String ContextPath = This.getservletcontext (). Getrealpath ("/");        System.setproperty ("RootPath", ContextPath);    }}

We set the default parameters of log4j log4j.configuration and our config file variable rootpath.

5. Using SLF4J to print logs in a class

Citation method:

Logger _log = Loggerfactory.getlogger (Slf4jtest.class);

Note that the object reference here is:
Import Org.slf4j.Logger;
Import Org.slf4j.LoggerFactory;

Then look at the printing method:

_log.debug ("Debug log: XXXXX");

Attach all source code:

/* File name: Com.qisentech.slf4j.demo.Slf4jTest.java * Date Created: 2013-8-23 11:02:20 * Created by: Qsyang */package Com.qisentech. Slf4j.demo;import org.slf4j.logger;import org.slf4j.loggerfactory;/** * <p>title: </p> * * <p> Description: </p> * * @author Qsyang * @version 1.0 */public class Slf4jtest {    private static Logger _log = Logg Erfactory.getlogger (slf4jtest.class);    public static void Testdebug (String info) {        System.out.println ("Testdebug");        _log.debug (info);    }    public static void TestInfo (String info) {        System.out.println ("TestInfo");        _log.info (info);    }    public static void Testwarn (String info) {        System.out.println ("Testwarn");        _log.warn (info);    }    public static void Testerror (String info) {        System.out.println ("Testerror");        _log.error (info);}    }

5. Do not forget to configure Web. xml

    <!--webplus Environment initialization (must start)-    <servlet>        <servlet-name>webpluscontextstart</ Servlet-name>        <servlet-class>com.qisentech.slf4j.demo.WebplusContextStart</servlet-class>        <load-on-startup>1</load-on-startup>    </servlet>

So the whole thing worked out.
The following will be the source attached, interested can go to download.

http://download.csdn.net/detail/yakson/7586371