log4j的使用-阿里云开发者社区

<slf4j-api.version>1.5.11</slf4j-api.version>
<log4j.version>1.2.16</log4j.version>
<slf4j-log4j12.version>1.5.6</slf4j-log4j12.version>
<dependency>
<groupId>com.alibaba.external</groupId>
<artifactId>org.slf4j.slf4j-api</artifactId>
<version>${slf4j-api.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.external</groupId>
<artifactId>jakarta.log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.external</groupId>
<artifactId>org.slf4j.slf4j-log4j12</artifactId>
<version>${slf4j-log4j12.version}</version>
</dependency>

<dependency>
<groupId>com.alibaba.external</groupId>
<artifactId>jakarta.log4j</artifactId>
<version>1.2.16</version>
</dependency>

知识点梳理：

（1）让下一次增加的log内容添加到log文件最后，而不是覆盖， <param name="Append" value=" true"/>

（2）分别控制每个部分的输出格式：分别在每种输出格式里面说明就可以了

（3）让console和file都输出：将文件输出样式和标准输出样式都加到root标签中。

<appender-ref ref="FILE" />

<appender-ref ref="STDOUT" />
（4）Log4j的继承

Parent类：

import org.apache.log4j.Logger;

public class Parent {
   protected static Logger    log = null; //不能为private
  Parent(){
    log= Logger.getLogger(getClass().getName());
  }
   public static void testParent(){
    log.info( "--hello parent!--");
  }
   public static void main(String[] args) {
     new Parent().testParent();
  }
}

Son类：

public class Son extends Parent {
   public void testSon(){
    log.info( "---hello son---"); //利用父类继承过来的log对象
  }
   public static void main(String[] args) {
     new Son().testSon();
  }
}

（5）输出格式转换

转换模式(conversion pattern)为"%r [%t] %-5p %c - %m%n"的PatternLayout将生成类似于以下内容的输出：
176 [main] INFO org.foo.Bar - Located nearest gas station.

在上面的输出中：
* 第一个字段表示自程序开始到发出日志记录请求时所消耗的毫秒数
* 第二个字段表示发出日志记录请求的线程
* 第三个字段表示日志记录请求的Level
* 第四个字段表示发出日志记录请求的Logger的名称
* 第五个字段(-后的文本)表示日志记录请求的消息

log4j的配置文件如下：

<? xml version ="1.0" encoding ="GB2312" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

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





< appender name ="LOG.DEBUG" class ="org.apache.log4j.RollingFileAppender" >
< param name ="File" value ="d:/log/debug.log" />
< param name ="MaxFileSize" value ="5120KB" />
< param name ="MaxBackupIndex" value ="10" />
< layout class ="org.apache.log4j.PatternLayout" >
     < param name ="ConversionPattern" value ="%d{yyy-MM-dd HH:mm:ss} [%-5p] %c {%F:%L} - %m%n" />
</ layout >
< filter class ="org.apache.log4j.varia.LevelRangeFilter" >
     < param name ="LevelMin" value ="DEBUG" />
     < param name ="LevelMax" value ="DEBUG" />
</ filter >
</ appender >


< appender name ="LOG.INFO" class ="org.apache.log4j.RollingFileAppender" >
< param name ="File" value ="d:/log/info.log" />
< param name ="MaxFileSize" value ="5120KB" />
< param name ="MaxBackupIndex" value ="10" />
< layout class ="org.apache.log4j.PatternLayout" >
     < param name ="ConversionPattern" value ="%d{yyy-MM-dd HH:mm:ss} [%-5p] %c {%F:%L} - %m%n" />
</ layout >
< filter class ="org.apache.log4j.varia.LevelRangeFilter" >
     < param name ="LevelMin" value ="INFO" />
     < param name ="LevelMax" value ="INFO" />
</ filter >
</ appender >


< appender name ="LOG.WARN" class ="org.apache.log4j.RollingFileAppender" >
< param name ="File" value ="d:/log/warn.log" />
< param name ="MaxFileSize" value ="5120KB" />
< param name ="MaxBackupIndex" value ="10" />
< layout class ="org.apache.log4j.PatternLayout" >
     < param name ="ConversionPattern" value ="%d{yyy-MM-dd HH:mm:ss} [%-5p] %c {%F:%L} - %m%n" />
</ layout >
< filter class ="org.apache.log4j.varia.LevelRangeFilter" >
     < param name ="LevelMin" value ="WARN" />
     < param name ="LevelMax" value ="WARN" />
</ filter >
</ appender >


< appender name ="LOG.ERROR" class ="org.apache.log4j.RollingFileAppender" >
< param name ="File" value ="d:/log/error.log" />
< param name ="MaxFileSize" value ="5120KB" />
< param name ="MaxBackupIndex" value ="10" />
< layout class ="org.apache.log4j.PatternLayout" >
     < param name ="ConversionPattern" value ="%d{yyy-MM-dd HH:mm:ss} [%-5p] %c {%F:%L} - %m%n" />
</ layout >
< filter class ="org.apache.log4j.varia.LevelRangeFilter" >
     < param name ="LevelMin" value ="ERROR" />
     < param name ="LevelMax" value ="ERROR" />
</ filter >
</ appender >


< appender name ="LOG.FATAL" class ="org.apache.log4j.RollingFileAppender" >
< param name ="File" value ="d:/log/fatal.log" />
< param name ="MaxFileSize" value ="5120KB" />
< param name ="MaxBackupIndex" value ="10" />
< layout class ="org.apache.log4j.PatternLayout" >
     < param name ="ConversionPattern" value ="%d{yyy-MM-dd HH:mm:ss} [%-5p] %c {%F:%L} - %m%n" />
</ layout >
< filter class ="org.apache.log4j.varia.LevelRangeFilter" >
     < param name ="LevelMin" value ="FATAL" />
     < param name ="LevelMax" value ="FATAL" />
</ filter >
</ appender >





< root >
< priority value ="DEBUG" />

< appender-ref ref ="LOG.DEBUG" />
< appender-ref ref ="LOG.INFO" />
< appender-ref ref ="LOG.WARN" />
< appender-ref ref ="LOG.ERROR" />
< appender-ref ref ="LOG.FATAL" />
</ root >

</ log4j:configuration >

log4j.xml另外一个模板

<? xml version ="1.0" encoding ="GB2312" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
< log4j:configuration xmlns:log4j ="http://jakarta.apache.org/log4j/" >

< appender name ="STDOUT" class ="org.apache.log4j.ConsoleAppender" >
                                
     < layout class ="org.apache.log4j.PatternLayout" >
      < param name ="ConversionPattern"
         value ="%-4r [%t] %-5p %c %x - %m%n" />
     </ layout >
                                
     < filter class ="org.apache.log4j.varia.LevelRangeFilter" >

      < param name ="levelMin" value ="INFO" />
      < param name ="levelMax" value ="ERROR" />

      < param name ="AcceptOnMatch" value ="true" />
     </ filter >
</ appender >

< appender name ="FILE"
     class ="org.apache.log4j.RollingFileAppender" >
    
     < param name ="File" value ="all.output.log" />
     < param name ="Append" value ="true" />
     < param name ="MaxBackupIndex" value ="10" />
     < layout class ="org.apache.log4j.PatternLayout" >
      < param name ="ConversionPattern" value ="%p (%c:%L)- %m%n" />
     </ layout >
</ appender >

< root >
     < priority value ="INFO" />
     < appender-ref ref ="FILE" />
     < appender-ref ref ="STDOUT" />
</ root >

</ log4j:configuration >

【注意】

1、Log4j设置循环记录日志文件

log4j.appender.fileout=org.apache.log4j.RollingFileAppender
log4j.appender.fileout.File=#### 为文件名，这个存放的位置为project工程的根目录
log4j.appender.fileout.MaxFileSize=5MB
log4j.appender.fileout.MaxBackupIndex=50
log4j.appender.fileout.layout=org.apache.log4j.PatternLayout
log4j.appender.fileout.layout.ConversionPattern=%d{ABSOLUTE} %-5p %t %c{5} - %m%n

某个类输出日志到某个log文件配置

log4j.rootLogger=info, stdout,console

log4j.appender.stdout=org.apache.log4j.DailyRollingFileAppender
log4j.appender.stdout.File=../log/updater.log
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %-17c{2} - %m%n
log4j.appender.stdout.Append=true

#console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %-17c{2} - %m%n
#log4j.appender.console.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p [%t] %-17c{2} (%13F:%L) %3x - %m%n

#app log

#com.wonibo.projectx.service.index.ReadTxtDaemon类使用warn级别且使用 txtfailure类型的appender

log4j.logger.com.wonibo.projectx.service.index.ReadTxtDaemon=warn, txtfailure

#未指定appender的则从root继承
log4j.logger.org.springframework=warn

log4j.logger.org.hibernate.ps.PreparedStatementCache=warn
log4j.logger.org.hibernate=warn
log4j.logger.org.hibernate.SQL=warn
log4j.logger.org.hibernate.type=warn

log4j.logger.com.danga.MemCached=warn
log4j.logger.org.apache.velocity=warn

log4j.appender. txtfailure=org.apache.log4j.FileAppender
log4j.appender. txtfailure.File=../log/txtfailure.log
log4j.appender. txtfailure.layout=org.apache.log4j.PatternLayout
log4j.appender. txtfailure.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %-17c{2} - %m%n
log4j.appender. txtfailure.Append=true

log4j.properties的放置位置

http://gigi-112.javaeye.com/blog/587965

public Logger m_log = null;
public ETrafficPlanService(){
PropertyConfigurator.configure("data//config//log4j//log4j_etraffic.properties");
m_log = Logger.getLogger(ETrafficPlanService.class);
m_log.debug("debug test...........");
}

问题总结：

1、 PropertyConfigurator.configure("src\\test\\java\\log4j.properties");//位置相对于工程根目录的位置为起点

【注意】只针对Properties文件有效，xml配置文件无效

读取XML配置文件： DOMConfigurator.configure ( String filename ) ：读取XML形式的配置文件

private Logger logger;
public MyThread() {
super();
//PropertyConfigurator.configure(System.getProperty("user.dir") + "/src/main/java/com/alibaba/thread/log.properties");
DOMConfigurator.configure(System.getProperty("user.dir") + "/src/main/java/com/alibaba/thread/log4j.xml");
logger = LoggerFactory.getLogger(this.getClass().getName());
}

【注意】

相对路径： DOMConfigurator.configure(this.getClass().getClassLoader().getResource("com/alibaba/thread/log4j.xml"));

绝对路径：

DOMConfigurator.configure(System.getProperty("user.dir") + "/src/main/java/com/alibaba/thread/log4j.xml");

2、log4j.appender.stdout.File=../log/updater.log //位置的起点为工程的根目录为起点

例如../log/updater.log:表示工程根目录的上级目录下的log,再生成updater.log文件

3、Logger

默认使用log4j.rootLogger，也可以自定义某些包或类的logger：log4j.logger.com.alibaba.maven.hello.Simple

log的日志级别：ALL< TRACE < DEBUG < INFO < WARN < ERROR < FATAL < OFF

常用为中间4种

4、Appender

AppenderSkeleton, AsyncAppender, ConsoleAppender, DailyRollingFileAppender, ExternallyRolledFileAppender, FileAppender, JDBCAppender, JMSAppender, LF5Appender, NTEventLogAppender, NullAppender, RollingFileAppender, SMTPAppender, SocketAppender, SocketHubAppender, SyslogAppender, TelnetAppender, WriterAppender

API： http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Appender.html

设置DailyRollingFileAppender时，可以设置之前的log修改成什么样的格式

log4j.appender.simple.DatePattern='_'yyyy-MM-dd

5、输出类型： layout

Simple layout-- org.apache.log4j.SimpleLayout
SimpleLayout formats the output in a very simple manner, it prints the Level, then a dash '-' and then the log message.

PatternLayout --org.apache.log4j.PatternLayout
PatternLayout formats the output based on a conversion pattern specified, or if none is specified, the default conversion pattern.

HTML layout-- org.apache.log4j.HTMLLayout
HTMLLayout formats the output as a HTML table.

XMLLayout-- org.apache.log4j.xml.XMLLayout
XMLLayout formats the output as a XML.

6、什么情况可以使用SLF4j

　　如果你开发的是类库或者嵌入式组件，那么就应该考虑采用SLF4J，因为不可能影响最终用户选择哪种日志系统。在另一方面，如果是一个简单或者独立的应用，确定只有一种日志系统，那么就没有使用SLF4J的必要。假设你打算将你使用log4j的产品卖给要求使用JDK 1.4 Logging的用户时，面对成千上万的log4j调用的修改，相信这绝对不是一件轻松的事情。但是如果开始便使用SLF4J，那么这种转换将是非常轻松的事情。

< dependency >
       < groupId >com.alibaba.external </ groupId >
       < artifactId >org.slf4j.slf4j-api </ artifactId >
       < version >1.5.11 </ version >
     </ dependency >
     < dependency >
       < groupId >com.alibaba.external </ groupId >
       < artifactId >jakarta.log4j </ artifactId >
       < version >1.2.16 </ version >
     </ dependency >

本文转自 tianya23 51CTO博客，原文链接：http://blog.51cto.com/tianya23/244266，如需转载请自行联系原作者

log4j的使用

<appender-ref ref="STDOUT" />
（4）Log4j的继承

（5）输出格式转换

1、Log4j设置循环记录日志文件

log4j.properties的放置位置

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log4j的使用

<appender-ref ref="STDOUT" /> （4）Log4j的继承

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1、Log4j设置循环记录日志文件

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<appender-ref ref="STDOUT" />
（4）Log4j的继承