Log4j

建立一个简单的工程.加上各种日志,LOG4J,COMMONLOGGING,SLF4J,LOGBACK所有JAR,及源码,做个比较.



pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>yan</groupId>
  <artifactId>logTest</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <dependencies>
  	<dependency>
  		<groupId>log4j</groupId>
  		<artifactId>log4j</artifactId>
  		<version>1.2.17</version>
  	</dependency>
  	<dependency>
  		<groupId>org.slf4j</groupId>
  		<artifactId>slf4j-api</artifactId>
  		<version>1.7.2</version>
  	</dependency>
     <dependency>
  		<groupId>org.slf4j</groupId>
  		<artifactId>jcl-over-slf4j</artifactId>
  		<version>1.7.2</version>
  	</dependency>
  	<dependency>
  		<groupId>org.slf4j</groupId>
  		<artifactId>slf4j-log4j12</artifactId>
  		<version>1.7.2</version>
  	</dependency>
  	<dependency>
  		<groupId>org.slf4j</groupId>
  		<artifactId>slf4j-simple</artifactId>
  		<version>1.6.1</version>
  	</dependency>
  	<dependency>
  		<groupId>ch.qos.logback</groupId>
  		<artifactId>logback-core</artifactId>
  		<version>1.0.6</version>
  	</dependency>
  	<dependency>
  		<groupId>ch.qos.logback</groupId>
  		<artifactId>logback-access</artifactId>
  		<version>1.0.9</version>
  	</dependency>
  	<dependency>
  		<groupId>ch.qos.logback</groupId>
  		<artifactId>logback-classic</artifactId>
  		<version>1.0.6</version>
  	</dependency>
    <dependency>
  		<groupId>commons-logging</groupId>
  		<artifactId>commons-logging</artifactId>
  		<version>1.1.2</version>
  	</dependency>
  </dependencies>
</project>

然后写一个类.代码入下.

import org.apache.log4j.Logger;
public class Log4jLogClass {
   private static org.apache.log4j.Logger log = Logger
                                    .getLogger(Log4jLogClass.class);
   public static void main(String[] args) {
      log.trace("Trace Message!");
      log.debug("Debug Message!");
      log.info("Info Message!");
      log.warn("Warn Message!");
      log.error("Error Message!");
      log.fatal("Fatal Message!");
   }
}

在resource目录下添加配置文件.



配置文件的内容:
log4j.rootLogger=debug, stdout, R

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

log4j.appender.stdout.layout.ConversionPattern=%5p - %m%n

log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=firestorm.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

log4j.logger.com.codefutures=DEBUG

然后再DEBUG源代码,以下为初始化时的调用栈:

owns: RootLogger  (id=26)
RollingFileAppender.<init>() line: 64
NativeConstructorAccessorImpl.newInstance0(Constructor, Object[]) line: not available [native method]
NativeConstructorAccessorImpl.newInstance(Object[]) line: 57
DelegatingConstructorAccessorImpl.newInstance(Object[]) line: 45
Constructor<T>.newInstance(Object...) line: 526
Class<T>.newInstance() line: 374
OptionConverter.instantiateByClassName(String, Class, Object) line: 337
OptionConverter.instantiateByKey(Properties, String, Class, Object) line: 124
PropertyConfigurator.parseAppender(Properties, String) line: 785
PropertyConfigurator.parseCategory(Properties, Logger, String, String, String) line: 768
PropertyConfigurator.configureRootCategory(Properties, LoggerRepository) line: 648
PropertyConfigurator.doConfigure(Properties, LoggerRepository) line: 514
PropertyConfigurator.doConfigure(URL, LoggerRepository) line: 580
OptionConverter.selectAndConfigure(URL, String, LoggerRepository) line: 526
LogManager.<clinit>() line: 127
Logger.getLogger(Class) line: 117
Log4jLogClass.<clinit>() line: 5


输出LOG的流程.




分文件输出LOG:
TestLog4j.rar