zno2

log4j 1.x

https://logging.apache.org/log4j/1.2/manual.html

1. log4j.dtd 在哪里？

log4j.jar 包中 org.apache.log4j.xml 下

<?xml version="1.0" encoding="UTF-8" ?>
<!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<!-- Authors: Chris Taylor, Ceki Gulcu. -->

<!-- Version: 1.2 -->

<!-- A configuration element consists of optional renderer
elements,appender elements, categories and an optional root
element. -->

<!ELEMENT log4j:configuration (renderer*, throwableRenderer?,
                               appender*,plugin*, (category|logger)*,root?,
                               (categoryFactory|loggerFactory)?)>

<!-- The "threshold" attribute takes a level value below which -->
<!-- all logging statements are disabled. -->

<!-- Setting the "debug" enable the printing of internal log4j logging   -->
<!-- statements.                                                         -->

<!-- By default, debug attribute is "null", meaning that we not do touch -->
<!-- internal log4j logging settings. The "null" value for the threshold -->
<!-- attribute can be misleading. The threshold field of a repository	 -->
<!-- cannot be set to null. The "null" value for the threshold attribute -->
<!-- simply means don't touch the threshold field, the threshold field   --> 
<!-- keeps its old value.                                                -->
     
<!ATTLIST log4j:configuration
  xmlns:log4j              CDATA #FIXED "http://jakarta.apache.org/log4j/" 
  threshold                (all|trace|debug|info|warn|error|fatal|off|null) "null"
  debug                    (true|false|null)  "null"
  reset                    (true|false) "false"
>

<!-- renderer elements allow the user to customize the conversion of  -->
<!-- message objects to String.                                       -->

<!ELEMENT renderer EMPTY>
<!ATTLIST renderer
  renderedClass  CDATA #REQUIRED
  renderingClass CDATA #REQUIRED
>

<!--  throwableRenderer allows the user to customize the conversion
         of exceptions to a string representation.  -->
<!ELEMENT throwableRenderer (param*)>
<!ATTLIST throwableRenderer
  class  CDATA #REQUIRED
>


<!-- Appenders must have a name and a class. -->
<!-- Appenders may contain an error handler, a layout, optional parameters -->
<!-- and filters. They may also reference (or include) other appenders. -->
<!ELEMENT appender (errorHandler?, param*,
      rollingPolicy?, triggeringPolicy?, connectionSource?,
      layout?, filter*, appender-ref*)>
<!ATTLIST appender
  name 		CDATA 	#REQUIRED
  class 	CDATA	#REQUIRED
>

<!ELEMENT layout (param*)>
<!ATTLIST layout
  class		CDATA	#REQUIRED
>

<!ELEMENT filter (param*)>
<!ATTLIST filter
  class		CDATA	#REQUIRED
>

<!-- ErrorHandlers can be of any class. They can admit any number of -->
<!-- parameters. -->

<!ELEMENT errorHandler (param*, root-ref?, logger-ref*,  appender-ref?)> 
<!ATTLIST errorHandler
   class        CDATA   #REQUIRED 
>

<!ELEMENT root-ref EMPTY>

<!ELEMENT logger-ref EMPTY>
<!ATTLIST logger-ref
  ref CDATA #REQUIRED
>

<!ELEMENT param EMPTY>
<!ATTLIST param
  name		CDATA   #REQUIRED
  value		CDATA	#REQUIRED
>


<!-- The priority class is org.apache.log4j.Level by default -->
<!ELEMENT priority (param*)>
<!ATTLIST priority
  class   CDATA	#IMPLIED
  value	  CDATA #REQUIRED
>

<!-- The level class is org.apache.log4j.Level by default -->
<!ELEMENT level (param*)>
<!ATTLIST level
  class   CDATA	#IMPLIED
  value	  CDATA #REQUIRED
>


<!-- If no level element is specified, then the configurator MUST not -->
<!-- touch the level of the named category. -->
<!ELEMENT category (param*,(priority|level)?,appender-ref*)>
<!ATTLIST category
  class         CDATA   #IMPLIED
  name		CDATA	#REQUIRED
  additivity	(true|false) "true"  
>

<!-- If no level element is specified, then the configurator MUST not -->
<!-- touch the level of the named logger. -->
<!ELEMENT logger (param*,level?,appender-ref*)>
<!ATTLIST logger
  class         CDATA   #IMPLIED
  name		CDATA	#REQUIRED
  additivity	(true|false) "true"  
>


<!ELEMENT categoryFactory (param*)>
<!ATTLIST categoryFactory 
   class        CDATA #REQUIRED>

<!ELEMENT loggerFactory (param*)>
<!ATTLIST loggerFactory
   class        CDATA #REQUIRED>

<!ELEMENT appender-ref EMPTY>
<!ATTLIST appender-ref
  ref CDATA #REQUIRED
>

<!-- plugins must have a name and class and can have optional parameters -->
<!ELEMENT plugin (param*, connectionSource?)>
<!ATTLIST plugin
  name 		CDATA 	   #REQUIRED
  class 	CDATA  #REQUIRED
>

<!ELEMENT connectionSource (dataSource?, param*)>
<!ATTLIST connectionSource
  class        CDATA  #REQUIRED
>

<!ELEMENT dataSource (param*)>
<!ATTLIST dataSource
  class        CDATA  #REQUIRED
>

<!ELEMENT triggeringPolicy ((param|filter)*)>
<!ATTLIST triggeringPolicy
  name 		CDATA  #IMPLIED
  class 	CDATA  #REQUIRED
>

<!ELEMENT rollingPolicy (param*)>
<!ATTLIST rollingPolicy
  name 		CDATA  #IMPLIED
  class 	CDATA  #REQUIRED
>


<!-- If no priority element is specified, then the configurator MUST not -->
<!-- touch the priority of root. -->
<!-- The root category always exists and cannot be subclassed. -->
<!ELEMENT root (param*, (priority|level)?, appender-ref*)>


<!-- ==================================================================== -->
<!--                       A logging event                                -->
<!-- ==================================================================== -->
<!ELEMENT log4j:eventSet (log4j:event*)>
<!ATTLIST log4j:eventSet
  xmlns:log4j             CDATA #FIXED "http://jakarta.apache.org/log4j/" 
  version                (1.1|1.2) "1.2" 
  includesLocationInfo   (true|false) "true"
>



<!ELEMENT log4j:event (log4j:message, log4j:NDC?, log4j:throwable?, 
                       log4j:locationInfo?, log4j:properties?) >

<!-- The timestamp format is application dependent. -->
<!ATTLIST log4j:event
    logger     CDATA #REQUIRED
    level      CDATA #REQUIRED
    thread     CDATA #REQUIRED
    timestamp  CDATA #REQUIRED
    time       CDATA #IMPLIED
>

<!ELEMENT log4j:message (#PCDATA)>
<!ELEMENT log4j:NDC (#PCDATA)>

<!ELEMENT log4j:throwable (#PCDATA)>

<!ELEMENT log4j:locationInfo EMPTY>
<!ATTLIST log4j:locationInfo
  class  CDATA	#REQUIRED
  method CDATA	#REQUIRED
  file   CDATA	#REQUIRED
  line   CDATA	#REQUIRED
>

<!ELEMENT log4j:properties (log4j:data*)>

<!ELEMENT log4j:data EMPTY>
<!ATTLIST log4j:data
  name   CDATA	#REQUIRED
  value  CDATA	#REQUIRED
>
log4j.dtd

2.  category和logger ，priority和level 区别？

org.apache.log4j.Category

This class has been deprecated and replaced by the Logger subclass.

org.apache.log4j.Priority
Refrain from using this class directly, use the Level class instead.
 
父子类关系，相同的效果，但避免使用Category 和 Priority
<!ELEMENT log4j:configuration (renderer*, appender*, plugin*, (category | logger)*, root?, (categoryFactory | loggerFactory)?)>
<!ELEMENT category (param*, (priority | level)?, appender-ref*)>
二选一，如果都出现会提示错误 log4j:WARN The content of element type "root" must match "(param*,(priority|level)?,appender-ref*)".
另外logger 中只能使用level （这是新的，新的里面当然不会使用老的，老的最终是要被淘汰的）
 
3. additivity

<!ATTLIST logger
name CDATA #REQUIRED
additivity (true | false) "true"
>

当匹配的一个最合适的logger（最具体的），同过additivity 控制是否向上蔓延，默认true

 

4. 继承

Level Inheritance

The inherited level for a given logger C, is equal to the first non-null level in the logger hierarchy, starting at C and proceeding upwards in the hierarchy towards the root logger.

从最具体的匹配开始，如果没有指定level则会继承第一个非空的祖先的level

 

Example 1

Logger
name		Assigned
level		Inherited
level
root Proot Proot
X none Proot
X.Y none Proot
X.Y.Z none Proot

In example 1 above, only the root logger is assigned a level. This level value, Proot, is inherited by the other loggers X, X.Y and X.Y.Z.

 

Example 2

Logger
name		Assigned
level		Inherited
level
root Proot Proot
X Px Px
X.Y Pxy Pxy
X.Y.Z Pxyz Pxyz

In example 2, all loggers have an assigned level value. There is no need for level inheritence.

 

Example 3

Logger
name		Assigned
level		Inherited
level
root Proot Proot
X Px Px
X.Y none Px
X.Y.Z Pxyz Pxyz

In example 3, the loggers root, X and X.Y.Z are assigned the levels Proot, Px and Pxyz respectively. The logger X.Y inherits its level value from its parent X.

Example 4
Logger
name		Assigned
level		Inherited
level
root Proot Proot
X Px Px
X.Y none Px
X.Y.Z none Px

 

 5. 具体例子

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

 

log4j.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/" debug="false">
    <!-- fileAppender -->
    <appender name="fileAppender" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="logs/test.log" />
        <param name="Append" value="true" />
        <param name="MaxFileSize" value="5000KB" />
        <param name="MaxBackupIndex" value="10" />
        <param name="encoding" value="UTF-8" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{MM/dd HH:mm:ss,SSS} [%c:%M:%-3L]-[%-5p] %m%n" />
        </layout>
    </appender>

    <logger name="a" additivity="true">
        <level value="INFO" />
        <appender-ref ref="fileAppender" />
    </logger>
    <logger name="a.b" additivity="true">
        <level value="DEBUG" />
        <appender-ref ref="fileAppender" />
    </logger>

    <root>
        <level value="ERROR" />
        <appender-ref ref="fileAppender" />
    </root>
</log4j:configuration>

 

package a;
import org.apache.log4j.Logger;

public class A {

    private static final Logger logger = Logger.getLogger(A.class);
    
    public void ff(){
        logger.trace(logger.getLevel());
        logger.debug(logger.getLevel());
        logger.info(logger.getLevel());
        logger.warn(logger.getLevel());
        logger.error(logger.getLevel());
    }
}

 

package a.b;
import org.apache.log4j.Logger;

public class AB {

    private static final Logger logger = Logger.getLogger(AB.class);
    
    public void ff(){
        logger.trace(logger.getLevel());
        logger.debug(logger.getLevel());
        logger.info(logger.getLevel());
        logger.warn(logger.getLevel());
        logger.error(logger.getLevel());
    }
}

 

import a.A;
import a.b.AB;

public class Test {

    public static void main(String[] args) {
        new A().ff();
        new AB().ff();
    }
}

 

打印结果：

02/07 12:16:20,033 [a.A:ff:11 ]-[INFO ] 
02/07 12:16:20,033 [a.A:ff:11 ]-[INFO ] 
02/07 12:16:20,036 [a.A:ff:12 ]-[WARN ] 
02/07 12:16:20,036 [a.A:ff:12 ]-[WARN ] 
02/07 12:16:20,036 [a.A:ff:13 ]-[ERROR] 
02/07 12:16:20,036 [a.A:ff:13 ]-[ERROR] 
02/07 12:16:20,036 [a.b.AB:ff:10 ]-[DEBUG] 
02/07 12:16:20,036 [a.b.AB:ff:10 ]-[DEBUG] 
02/07 12:16:20,036 [a.b.AB:ff:10 ]-[DEBUG] 
02/07 12:16:20,036 [a.b.AB:ff:11 ]-[INFO ] 
02/07 12:16:20,036 [a.b.AB:ff:11 ]-[INFO ] 
02/07 12:16:20,036 [a.b.AB:ff:11 ]-[INFO ] 
02/07 12:16:20,036 [a.b.AB:ff:12 ]-[WARN ] 
02/07 12:16:20,036 [a.b.AB:ff:12 ]-[WARN ] 
02/07 12:16:20,036 [a.b.AB:ff:12 ]-[WARN ] 
02/07 12:16:20,038 [a.b.AB:ff:13 ]-[ERROR] 
02/07 12:16:20,038 [a.b.AB:ff:13 ]-[ERROR] 
02/07 12:16:20,038 [a.b.AB:ff:13 ]-[ERROR]

 

6. 开启自身内部的调试信息

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

打印结果：

log4j: reset attribute= "false".
log4j: Threshold ="null".
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [a] additivity to [true].
log4j: Level value for a is  [INFO].
log4j: a level set to INFO
log4j: Class name: [org.apache.log4j.RollingFileAppender]
log4j: Setting property [file] to [logs/test.log].
log4j: Setting property [append] to [true].
log4j: Setting property [maxFileSize] to [5000KB].
log4j: Setting property [maxBackupIndex] to [10].
log4j: Setting property [encoding] to [UTF-8].
log4j: Parsing layout of class: "org.apache.log4j.PatternLayout"
log4j: Setting property [conversionPattern] to [%d{MM/dd HH:mm:ss,SSS} [%c:%M:%-3L]-[%-5p] %m%n].
log4j: setFile called: logs/test.log, true
log4j: setFile ended
log4j: Adding appender named [fileAppender] to category [a].
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [a.b] additivity to [true].
log4j: Level value for a.b is  [DEBUG].
log4j: a.b level set to DEBUG
log4j: Adding appender named [fileAppender] to category [a.b].
log4j: Level value for root is  [ERROR].
log4j: root level set to ERROR
log4j: Adding appender named [fileAppender] to category [root].

 

posted on 2023-06-06 13:14  zno2  阅读(35)  评论(0)    收藏  举报

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