源码网商城,靠谱的源码在线交易网站 我的订单 购物车 帮助

源码网商城

浅谈在JAVA项目中LOG4J的使用

  • 时间:2022-10-19 21:11 编辑: 来源: 阅读:
  • 扫一扫,手机访问
摘要:浅谈在JAVA项目中LOG4J的使用
[b]一、直接使用:[/b]
//输出到项目文件夹下output1.txt文件中

//////////////////////////////

// DEBUG - Here is some DEBUG

// INFO - Here is some INFO

// WARN - Here is some WARN

// ERROR - Here is some ERROR

// FATAL - Here is some FATAL

//////////////////////////////

package hunnu.sanha.test;

import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.apache.log4j.SimpleLayout;

import org.apache.log4j.FileAppender;

public class Simpandfile {

 static Logger logger = Logger.getLogger(Simpandfile.class);

 public static void main(String args[]) {

  SimpleLayout layout = new SimpleLayout();

  FileAppender appender = null;

  try {

   appender = new FileAppender(layout,"output1.txt",false);

  } catch(Exception e) {}

  logger.addAppender(appender);

  logger.setLevel((Level) Level.);

  logger.debug("Here is some DEBUG");

  logger.info("Here is some INFO");

  logger.warn("Here is some WARN");

  logger.error("Here is some ERROR");

  logger.fatal("Here is some FATAL");

 }

}

 

//按格式输出到项目文件夹下output2.html

package hunnu.sanha.test;

import java.io.*;

import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.apache.log4j.HTMLLayout;

import org.apache.log4j.WriterAppender;

public class Htmlandwrite {

 static Logger logger = Logger.getLogger(Htmlandwrite.class);

 public static void main(String args[]) {

  HTMLLayout layout = new HTMLLayout();

  WriterAppender appender = null;

  try {

   FileOutputStream output = new FileOutputStream("output2.html");

   appender = new WriterAppender(layout,output);

  } catch(Exception e) {}

  logger.addAppender(appender);

  logger.setLevel((Level) Level.);

  logger.debug("Here is some DEBUG");

  logger.info("Here is some INFO");

  logger.warn("Here is some WARN");

  logger.error("Here is some ERROR");

  logger.fatal("Here is some FATAL");

 }

}

 

 

//输出到控制台

////////////////////////////////////////////////////////////////////////////////////////////////////////////

Milliseconds since program start: 0

Classname of caller: hunnu.sanha.test.Consandpatt

Date in ISO8601 format: 2008-07-29 11:02:30,578

Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:20)

Message: Here is some DEBUG

 

Milliseconds since program start: 15

Classname of caller: hunnu.sanha.test.Consandpatt

Date in ISO8601 format: 2008-07-29 11:02:30,593

Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:21)

Message: Here is some INFO

 

Milliseconds since program start: 15

Classname of caller: hunnu.sanha.test.Consandpatt

Date in ISO8601 format: 2008-07-29 11:02:30,593

Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:22)

Message: Here is some WARN

 

Milliseconds since program start: 15

Classname of caller: hunnu.sanha.test.Consandpatt

Date in ISO8601 format: 2008-07-29 11:02:30,593

Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:23)

Message: Here is some ERROR

 

Milliseconds since program start: 15

Classname of caller: hunnu.sanha.test.Consandpatt

Date in ISO8601 format: 2008-07-29 11:02:30,593

Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:24)

Message: Here is some FATAL

///////////////////////////////////////////////////////

package hunnu.sanha.test;

import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.apache.log4j.PatternLayout;

import org.apache.log4j.ConsoleAppender;

public class Consandpatt {

 static Logger logger = Logger.getLogger(Consandpatt.class);

 public static void main(String args[]) {

  // Note, %n is newline

  String pattern = "Milliseconds since program start: %r %n";

    pattern += "Classname of caller: %C %n";

    pattern += "Date in ISO8601 format: %d{ISO8601} %n";

    pattern += "Location of log event: %l %n";

    pattern += "Message: %m %n %n";

  

  PatternLayout layout = new PatternLayout(pattern);

  ConsoleAppender appender = new ConsoleAppender(layout);

  logger.addAppender(appender);

  logger.setLevel((Level) Level.);

  logger.debug("Here is some DEBUG");

  logger.info("Here is some INFO");

  logger.warn("Here is some WARN");

  logger.error("Here is some ERROR");

  logger.fatal("Here is some FATAL");

 }

}
[b]二、使用配置文件(都直接放到项目文件夹下)[/b]
//xmllog4jconfig.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">

 <appender name="appender" class="org.apache.log4j.FileAppender">

  <param name="File" value="Indentify-Log.txt"/>

  <param name="Append" value="false"/>

  <layout class="org.apache.log4j.PatternLayout">

  <param name="ConversionPattern" value="%d [%t] %p - %m%n"/>

  </layout>

 </appender>

 <root>

  <priority value ="debug"/>

  <appender-ref ref="appender"/>

 </root>

</log4j:configuration>

 

//Externalxmltest.java

 package hunnu.sanha.external;

import org.apache.log4j.Logger;

import org.apache.log4j.xml.DOMConfigurator;

public class Externalxmltest {

 static Logger logger = Logger.getLogger(Externalxmltest.class);

 public static void main(String args[]) {

  DOMConfigurator.configure("xmllog4jconfig.xml");

  logger.debug("Here is some DEBUG");

  logger.info("Here is some INFO");

  logger.warn("Here is some WARN");

  logger.error("Here is some ERROR");

  logger.fatal("Here is some FATAL");

 }

}

//结果输出到Indentify-Log.txt文件中

2008-07-29 10:48:11,375 [main] DEBUG - Here is some DEBUG

2008-07-29 10:48:11,375 [main] INFO - Here is some INFO

2008-07-29 10:48:11,375 [main] WARN - Here is some WARN

2008-07-29 10:48:11,375 [main] ERROR - Here is some ERROR

2008-07-29 10:48:11,375 [main] FATAL - Here is some FATAL

 

 

// plainlog4jconfig.txt

# initialise root logger with level DEBUG and call it BLAH

log4j.rootLogger=DEBUG, BLAH

# add a ConsoleAppender to the logger BLAH

log4j.appender.BLAH=org.apache.log4j.ConsoleAppender

# set set that layout to be SimpleLayout

log4j.appender.BLAH.layout=org.apache.log4j.SimpleLayout

 

//Externalplaintest.java

package hunnu.sanha.external;

import org.apache.log4j.Logger;

import org.apache.log4j.PropertyConfigurator;

public class Externalplaintest {

 static Logger logger = Logger.getLogger(Externalplaintest.class);

 public static void main(String args[]) {

  PropertyConfigurator.configure("plainlog4jconfig.txt");

  logger.debug("Here is some DEBUG");

  logger.info("Here is some INFO");

  logger.warn("Here is some WARN");

  logger.error("Here is some ERROR");

  logger.fatal("Here is some FATAL");

 }

}

//结果输出到控制台

DEBUG - Here is some DEBUG

INFO - Here is some INFO

WARN - Here is some WARN

ERROR - Here is some ERROR

FATAL - Here is some FATAL
附加: [b]2.1.   日志信息的优先级[/b] 分为OFF、FATAL、ERROR、WARN、INFO、DEBUG、ALL或者您定义的级别。 Log4j建议只使用四个级别,优先级从高到低分别是ERROR、WARN、INFO、DEBUG。通过在这里定义的级别,您可以控制到应用程序中相应级别的日志信息的开关。 假如在一个级别为q的Logger中发生一个级别为p的日志请求,如果p>=q,那么请求将被启用。这是Log4j的核心原则。 比如在这里定义了INFO级别,则应用程序中所有DEBUG级别的日志信息将不被打印出来; [b]2.2.   输出源的使用[/b] 有选择的能用或者禁用日志请求仅仅是Log4j的一部分功能。Log4j允许日志请求被输出到多个输出源。用Log4j的话说,一个输出源被称做一个Appender。 Appender包括console(控制台), files(文件), GUI components(图形的组件), remote socket servers(socket 服务), JMS(java信息服务), NT Event Loggers(NT的事件日志), and remote UNIX Syslog daemons(远程UNIX的后台日志服务)。它也可以做到异步记录。 一个logger可以设置超过一个的appender。 用addAppender 方法添加一个appender到一个给定的logger。对于一个给定的logger它每个生效的日志请求都被转发到该logger所有的appender上和该logger的父辈logger的appender上。 [b]2.2.1.  ConsoleAppender[/b] 如果使用ConsoleAppender,那么log信息将写到Console。效果等同于直接把信息打印到System.out上了。 [b]2.2.2.  FileAppender[/b] 使用FileAppender,那么log信息将写到指定的文件中。这应该是比较经常使用到的情况。 相应地,在配置文件中应该指定log输出的文件名。如下配置指定了log文件名为dglog.txt log4j.appender.A2.File=dglog.txt 注意将A2替换为具体配置中Appender的别名。 [b]2.2.3.  DailyRollingAppender[/b] 使用FileAppender可以将log信息输出到文件中,但是如果文件太大了读起来就不方便了。这时就可以使用DailyRollingAppender。DailyRollingAppender可以把Log信息输出到按照日期来区分的文件中。配置文件就会每天产生一个log文件,每个log文件只记录当天的log信息: log4j.appender.A2=org.apache.log4j.DailyRollingFileAppender log4j.appender.A2.file=dglog log4j.appender.A2.DatePattern='.'yyyy-MM-dd log4j.appender.A2.layout=org.apache.log4j.PatternLayout log4j.appender.A2.layout.ConversionPattern= %5r %-5p %c{2} - %m%n [b]2.2.4.  org.apache.log4j.RollingFileAppender[/b] 文件大小到达指定尺寸的时候产生一个新的文件。 log4j.appender.R=org.apache.log4j.RollingFileAppender log4j.appender.R.File= ../logs/dglog.log # Control the maximum log file size log4j.appender.R.MaxFileSize=100KB # Archive log files (one backup file here) log4j.appender.R.MaxBackupIndex=1 log4j.appender.R.layout=org.apache.log4j.PatternLayout log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n 这个配置文件指定了输出源R,是一个轮转日志文件。最大的文件是100KB,当一个日志文件达到最大尺寸时,Log4J会自动把example.log重命名为dglog.log.1,然后重建一个新的dglog.log文件,依次轮转。 [b]2.2.5.  org.apache.log4j.WriterAppender[/b] 将日志信息以流格式发送到任意指定的地方。 [b]2.3.  Layout的配置[/b] Layout指定了log信息输出的样式。 [b]2.3.1.  布局样式[/b] org.apache.log4j.HTMLLayout(以HTML表格形式布局), org.apache.log4j.PatternLayout(可以灵活地指定布局模式), org.apache.log4j.SimpleLayout(包含日志信息的级别和信息字符串), org.apache.log4j.TTCCLayout(包含日志产生的时间、线程、类别等等信息) [b]2.3.2.  格式[/b] %m 输出代码中指定的消息 %p 输出优先级,即DEBUG,INFO,WARN,ERROR,FATAL %r 输出自应用启动到输出该log信息耗费的毫秒数 %c 输出所属的类目,通常就是所在类的全名 %t 输出产生该日志事件的线程名 %n 输出一个回车换行符,Windows平台为"rn",Unix平台为"n" %d 输出日志时间点的日期或时间,默认格式为ISO8601,也可以在其后指定格式,比如:%d{yyy MMM dd HH:mm:ss,SSS},输出类似:2002年10月18日 22:10:28,921 %l 输出日志事件的发生位置,包括类目名、发生的线程,以及在代码中的行数。举例:Testlog4.main(Test Log4.java:10) [b]2.3.3.  例子[/b] [b]例子1:显示日期和log信息 [/b]log4j.appender.A2.layout=org.apache.log4j.PatternLayout log4j.appender.A2.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %m%n 打印的信息是: 2002-11-12 11:49:42,866 SELECT * FROM Role WHERE 1=1 order by createDate desc [b]例子2:显示日期,log发生地方和log信息 [/b]log4j.appender.A2.layout=org.apache.log4j.PatternLayout log4j.appender.A2.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %l "#" %m%n 2002-11-12 11:51:46,313 cn.net.unet.weboa.system.dao.RoleDAO.select(RoleDAO.java:409) "#" SELECT * FROM Role WHERE 1=1 order by createDate desc    [b]例子3:显示log级别,时间,调用方法,log信息 [/b]log4j.appender.A2.layout=org.apache.log4j.PatternLayout log4j.appender.A2.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n log信息: [DEBUG] 2002-11-12 12:00:57,376 method:cn.net.unet.weboa.system.dao.RoleDAO.select(RoleDAO.java:409) SELECT * FROM Role WHERE 1=1 order by createDate desc [b]2.4.   配置文件的例子:[/b] log4j.rootLogger=DEBUG #将DAO层log记录到DAOLog,allLog中 log4j.logger.DAO=DEBUG,A2,A4 #将逻辑层log记录到BusinessLog,allLog中 log4j.logger.Businesslog=DEBUG,A3,A4 [b]#A1--打印到屏幕上 [/b]log4j.appender.A1=org.apache.log4j.ConsoleAppender log4j.appender.A1.layout=org.apache.log4j.PatternLayout log4j.appender.A1.layout.ConversionPattern=%-5p [%t] %37c %3x - %m%n [b]#A2--打印到文件DAOLog中--专门为DAO层服务 [/b]log4j.appender.A2=org.apache.log4j.DailyRollingFileAppender log4j.appender.A2.file=DAOLog log4j.appender.A2.DatePattern='.'yyyy-MM-dd log4j.appender.A2.layout=org.apache.log4j.PatternLayout log4j.appender.A2.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n [b]#A3--打印到文件BusinessLog中--专门记录逻辑处理层服务log信息 [/b]log4j.appender.A3=org.apache.log4j.DailyRollingFileAppender log4j.appender.A3.file=BusinessLog log4j.appender.A3.DatePattern='.'yyyy-MM-dd log4j.appender.A3.layout=org.apache.log4j.PatternLayout log4j.appender.A3.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n [b]#A4--打印到文件alllog中--记录所有log信息 [/b]log4j.appender.A4=org.apache.log4j.DailyRollingFileAppender log4j.appender.A4.file=alllog log4j.appender.A4.DatePattern='.'yyyy-MM-dd log4j.appender.A4.layout=org.apache.log4j.PatternLayout log4j.appender.A4.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n 以上这篇浅谈在JAVA项目中LOG4J的使用就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持编程素材网。
  • 全部评论(0)
联系客服
客服电话:
400-000-3129
微信版

扫一扫进微信版
返回顶部