【简单粗暴】建立Java的Log4j 日志打印工具

首先要导入相关jar包，其次在工程 resource目录下建立下面两个文件就ok。

log4j.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="STDOUT" class="org.apache.log4j.ConsoleAppender"><layout class="org.apache.log4j.PatternLayout"><param name="ConversionPattern" value="%d{yy-MM-dd HH:mm:ss,SSS} %-5p %c - %m%n" /></layout></appender><appender name="ST_DEBUG" class="org.apache.log4j.DailyRollingFileAppender">           <param name="File" value="${catalina.home}/log/Glory_web/debug.log" />      <param name="DatePattern" value="'-'yyyy-MM-dd'.log'" /> <param name="Append" value="true" /> <param name="Threshold" value="DEBUG"/>     <layout class="org.apache.log4j.PatternLayout">            <param name="ConversionPattern" value="%d{yy-MM-dd HH:mm:ss,SSS} %-5p %c - %m%n"/>          </layout>   </appender>   <appender name="ST_INFO" class="org.apache.log4j.DailyRollingFileAppender">           <param name="File" value="${catalina.home}/log/Glory_web/info.log" />      <param name="DatePattern" value="'-'yyyy-MM-dd'.log'" /> <param name="Append" value="true" /> <param name="Threshold" value="INFO"/>     <layout class="org.apache.log4j.PatternLayout">            <param name="ConversionPattern" value="%d{yy-MM-dd HH:mm:ss,SSS} %-5p %c - %m%n"/>          </layout>   </appender>   <appender name="ST_ERROR" class="org.apache.log4j.DailyRollingFileAppender">           <param name="File" value="${catalina.home}/log/Glory_web/error.log" />      <param name="DatePattern" value="'-'yyyy-MM-dd'.log'" /> <param name="Append" value="true" /> <param name="Threshold" value="ERROR"/>     <layout class="org.apache.log4j.PatternLayout">            <param name="ConversionPattern" value="%d{yy-MM-dd HH:mm:ss,SSS} %-5p %c - %m%n"/>          </layout>   </appender>   <root><level value="INFO" /><appender-ref ref="STDOUT" /><appender-ref ref="ST_DEBUG" /><appender-ref ref="ST_INFO" /><appender-ref ref="ST_ERROR" /></root></log4j:configuration>

log4j.dtd:

<?xml version="1.0" encoding="UTF-8" ?><!-- Authors: Chris Taylor, Ceki Gulcu. --><!-- Version: 1.2 --><!-- A configuration element consists of optional rendererelements,appender elements, categories and an optional rootelement. --><!ELEMENT log4j:configuration (renderer*, appender*,(category|logger)*,root?,                               categoryFactory?)><!-- The "threshold" attribute takes a level value such that all --><!-- logging statements with a level equal or below this value 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|debug|info|warn|error|fatal|off|null) "null"  debug                    (true|false|null)  "null"><!-- 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><!-- 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*, layout?, filter*, appender-ref*)><!ATTLIST appender  name ID #REQUIRED  class CDATA#REQUIRED><!ELEMENT layout (param*)><!ATTLIST layout  classCDATA#REQUIRED><!ELEMENT filter (param*)><!ATTLIST filter  classCDATA#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 IDREF #REQUIRED><!ELEMENT param EMPTY><!ATTLIST param  nameCDATA   #REQUIRED  valueCDATA#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  nameCDATA#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 (level?,appender-ref*)><!ATTLIST logger  nameID#REQUIRED  additivity(true|false) "true"  ><!ELEMENT categoryFactory (param*)><!ATTLIST categoryFactory    class        CDATA #REQUIRED><!ELEMENT appender-ref EMPTY><!ATTLIST appender-ref  ref IDREF #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?) ><!-- The timestamp format is application dependent. --><!ATTLIST log4j:event    logger     CDATA #REQUIRED    level      CDATA #REQUIRED    thread     CDATA #REQUIRED    timestamp  CDATA #REQUIRED><!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>