logbackFilter机制.docx

logbackFilter机制.docx

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logbackFilter机制

logback-Filter机制

logback-Filter机制关键字:

logbackhttp:

//logback.qos.ch/manual/filters.html译自官方文档。

其实看看也不是很难懂，就是看过后动手写一次，可能会加强印象吧。

最近被log4j整郁闷了，针对多样化的分类输出无所适从，只能开多个写死的appender来凑合。

Aswehaveseen,logbackhasseveralbuilt-inwaysforfilteringlogrequests,includingthecontext-widefilter,logger-levelselectionruleandappenderfilters.Theseprovidehighperformancefilteringforthemostcommonlyencounteredcases.ThesefiltersarelargelyinspiredfromLinuxipchainsoriptablesastheyarecalledinmorerecentLinuxkernels.Logbackfiltersarebasedonternarylogicallowingthemtobeassembledorchainedtogethertocomposeanarbitrarilycomplexfilteringpolicy.logback提供了一些自带的过滤机制，包含上下文过滤，日志级别过滤，Appender输出过滤等。

他们提供了高性能的、满足最常用场景的过滤实现。

这些过滤机制很大程度上来源自linux中ipchains/iptables的灵感。

Logback提供的Filter可以通过三元逻辑运算来组合过滤链来实现复杂的过滤需求。

Therearetwomaintypesoffilters,namelyFilterandTurboFilter.重点是两种抽象的Filter类型，filters,TurboFilter.LogbackClassicFiltersarebasedonternarylogic.Thedecide（Object

event）methodofeachfilteriscalledinsequence.ThismethodreturnsoneoftheFilterReplyenumerationvalues,i.e.oneofFilterReply.DENY,FilterReply.NEUTRALorFilterReply.ACCEPT.IfthereturnedvalueisFilterReply.DENY,thenthelogeventisdroppedimmediatelywithoutconsultingtheremainingfilters.IfthevaluereturnedisFilterReply.NEUTRAL,thenthenextfilterinthechainisconsulted.Iftherearenofurtherfilterstoconsult,thentheloggingeventisprocessednormally.IfthereturnedvalueisFilterReply.ACCEPT,thentheloggingeventisprocessedimmediatelyskippingtheremainingfilters.过滤器是串行工作的，有3种FilterReply结果，DENY,NEUTRAL,ACCEPT.他们之间通过逻辑运算来得到最终处理过程。

ImplementingyourownFilterCreatingyourownfilterisnotdifficult.AllyouhavetodoisextendtheFilterabstractclass.Theonlymethodthatyouwillhavetoimplementisthedecide（）method,allowingyoutocontentrateonlyonthebehaviourofyourfilter.Thenextclassisallittakestoimplementone'sownfilter.Allitdoesisacceptloggingeventswho'smessagecontainstheStringsample.Thefilterwillgiveaneutralresponsetoanyloggingeventwho'smessagedoesnotcontainthisString.Example6.1:

Basiccustomfilter（logback-examples/src/main/java/chapter6/SampleFilter.java）我们简单的实现过滤类，Java代码packagechapter6;importch.qos.logback.classic.spi.LoggingEvent;importch.qos.logback.core.filter.Filter;importch.qos.logback.core.spi.FilterReply;publicclassSampleFilterextendsFilter{@OverridepublicFilterReplydecide（ObjecteventObject）{LoggingEventevent=（LoggingEvent）eventObject;if（event.getMessage（）.contains（"sample"））{returnFilterReply.ACCEPT;}else{returnFilterReply.NEUTRAL;}}}然后配置如下：

Xml代码<configuration><appendername="STDOUT"class="ch.qos.logback.core.ConsoleAppender"><Filterclass="chapter6.SampleFilter"/><layoutclass="ch.qos.logback.classic.PatternLayout"><pattern>%-4relative[%thread]%-5level%logger-%msg%n</pattern></layout></appender><root><appender-refref="STDOUT"/></root></configuration>LogbackFilters1.Atthemoment,therearetwofiltersthatshipwithlogback.LevelFilterprovideseventfilteringbasedonaLevelvalue.Iftheevent'slevelisequaltotheconfiguredlevel,thefilteracceptsordeniestheevent,dependingonitsconfiguration.Itallowsyoutochoosethebehaviouroflogbackforaprecisegivenlevel.级别过滤Filter。

相等判断==Xml代码<filterclass="ch.qos.logback.classic.filter.LevelFilter"><level>INFO</level><onMatch>ACCEPT</onMatch><onMismatch>DENY</onMismatch></filter>2.ThesecondfilterthatshipswithlogbackisThresholdFilter.Itisalsobasedonlevelvalue,butactsasathresholdtodenyanyrequestwhoselevelisnotequalorgreatertotheconfiguredlevel.AsampleuseoftheThresholdFilterisshownbelow.级别过滤，临界点判断,>=Xml代码<filterclass="ch.qos.logback.classic.filter.ThresholdFilter"><level>INFO</level></filter>EvaluatorFilterstakingJavaExpressions正则式。

。

标配文档用图标列出了可以匹配的内容，请查阅源文档页面Java代码<configuration><appendername="STDOUT"class="ch.qos.logback.core.ConsoleAppender"><filterclass="ch.qos.logback.core.filter.EvaluatorFilter"><evaluatorname="myEval"><expression>message.contains（"billing"）</expression></evaluator><OnMismatch>NEUTRAL</OnMismatch><OnMatch>DENY</OnMatch></filter><layout><pattern>%-4relative[%thread]%-5level%logger-%msg%n</pattern></layout></appender><rootlevel="INFO"><appender-refref="STDOUT"/></root></configuration>TurboFiltersTurboFilterobjectsallextendtheTurboFilterabstractclass.Liketheregularfilters,theyuseternarylogictoreturntheirevaluationoftheloggingevent.Overall,theyworkmuchlikethepreviouslymentionnedfilters.However,therearetwomaindifferencesbetweenFilterandTurboFilterobjects.TuboFilter跟Filter有两个主要区别：

TurboFilterobjectsaretiedtotheloggingcontext.Hence,theyarecallednotonlywhenagivenappenderisused,buteachandeverytimealoggingrequestisissued.Theirscopeiswiderthanappender-attachedfilters.1.TurboFilter会试图记录上下文环境。

因此他们会在每次logging请求产生的时候调用，而不是一个指定的appender使用时才出现。

Moreimportantly,theyarecalledbeforetheLoggingEventobjectcreation.TurboFilterobjectsdonotrequiretheinstantiationofaloggingeventtofilteraloggingrequest.Assuch,turbofiltersareintendedforhighperformancefilteringofloggingevent,evenbeforetheyarecreated2.更重要的是，TurboFilter会在日志事件对象创建前调用。

因此它具有更高性能的过滤日志事件，即使在事件被创建之前。

Java代码packagechapter6;importorg.slf4j.Marker;importorg.slf4j.MarkerFactory;importch.qos.logback.classic.Level;importch.qos.logback.classic.Logger;importch.qos.logback.classic.turbo.TurboFilter;importch.qos.logback.core.spi.FilterReply;publicclassSampleTurboFilterextendsTurboFilter{Stringmarker;MarkermarkerToAccept;@OverridepublicFilterReplydecide（Markermarker,Loggerlogger,Levellevel,Stringformat,Object[]params,Throwablet）{if（!

isStarted（））{returnFilterReply.NEUTRAL;}if（（markerToAccept.equals（marker）））{returnFilterReply.ACCEPT;}else{returnFilterReply.NEUTRAL;}}publicStringgetMarker（）{returnmarker;}publicvoidsetMarker（StringmarkerStr）{this.marker=markerStr;}@Overridepublicvoidstart（）{if（marker!

=null&&marker.trim（）.length（）>0）{markerToAccept=MarkerFactory.getMarker（marker）;super.start（）;}}}上例对具体的maker做了过滤，配置当然简单Xml代码<configuration><turboFilterclass="chapter6.SampleTurboFilter"><Marker>sample</Marker></turboFilter><appendername="STDOUT"class="ch.qos.logback.core.ConsoleAppender"><layoutclass="ch.qos.logback.classic.PatternLayout"><pattern>%-4relative[%thread]%-5level%logger-%msg%n</pattern></layout></appender><root><appender-refref="STDOUT"/></root></configuration>LogbackclassicshipswithseveralTurboFilterclassesreadyforuse.TheMDCFiltercheckthepresenceofagivenvalueintheMDCwhereasDynamicThresholdFilterallowsfilteringbasedonMDCkey/levelthresoldassociations.Ontheotherhand,MarkerFilterchecksforthepresenceofaspecificmarkerassociatedwiththeloggingrequest.Logback已经实现了3个基本的TurboFilter，MDCFilterDynamicThresholdFilterMarkerFilterXml代码<turboFilterclass="ch.qos.logback.classic.turbo.MDCFilter"><MDCKey>username</MDCKey><Value>sebastien</Value><OnMatch>ACCEPT</OnMatch></turboFilter><turboFilterclass="ch.qos.logback.classic.turbo.MarkerFilter"><Marker>billing</Marker><OnMatch>DENY</OnMatch></turboFilter>Logback-access记录操作

Logback-accessoffersmostofthefeaturesavailablewithlogback-classic.Filterobjectsareavailableandworkinthesamewayastheirlogback-classiccounterparts.Theyhandleaccess'implementationofloggingevents:

AccessEvent.Thus,acustomizedfilterforlogbackaccessfollowsstrictlythesamerulesasthoseforlogback-classic,exceptfortheeventtyperecievedasparameter.Ontheotherhand,TurboFilterobjectsaresupportedbylogback-access.一个可以保证所有404错误都会被记录的例子！

！

（这个很有效）Xml代码<configuration><appendername="STDOUT"class="ch.qos.logback.core.ConsoleAppender"><filterclass="ch.qos.logback.core.filter.EvaluatorFilter"><evaluatorname="myEval"><expression>event.getStatusCode（）==404</expression></evaluator><OnMismatch>NEUTRAL</OnMismatch><OnMatch>ACCEPT</OnMatch></filter><layoutclass="ch.qos.logback.access.PatternLayout"><pattern>%h%l%u%t%r%s%b</pattern></layout></appender><appender-refref="STDOUT"/></configuration>更高级的示例：

记录不返回css资源的所有404Xml代码<configuration><appendername="STDOUT"class="ch.qos.logback.core.ConsoleAppender"><filterclass="ch.qos.logback.core.filter.EvaluatorFilter"><evaluatorname="Eval404"><expression>event.getStatusCode（）==404</expression></evaluator><OnMismatch>NEUTRAL</OnMismatch><OnMatch>ACCEPT</OnMatch></filter><filterclass="ch.qos.logback.core.filter.EvaluatorFilter"><evaluatorname="EvalCSS"><expression>event.getRequestURI（）.contains（"css"）</expression></evaluator><OnMismatch>NEUTRAL</OnMismatch><OnMatch>DENY</OnMatch></filter><layoutclass="ch.qos.logback.access.PatternLayout"><pattern>%h%l%u%t%r%s%b</pattern></layout></appender><appender-refref="STDOUT"/></configuration