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Editor to share with you how log4j controls the log output file name, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

Log4j control log output file name 1. The first way

Define the logger variable in the class object as follows

Private static Logger logger = Logger.getLogger ("lemmaXml")

To obtain logger by name, you need to define an appender named lemmaXml in the log4j.properties file. The configuration is as follows:

Log4j.logger.lemmaXml=INFO,lemmaXmllog4j.appender.lemmaXml=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.lemmaXml.Threshold=DEBUGlog4j.appender.lemmaXml.File=$ {catalina.home} / logs/lemmaXml.loglog4j.appender.lemmaXml.layout=org.apache.log4j.PatternLayoutlog4j.appender.lemmaXml.layout.ConversionPattern=%5p d {yyyy-MM-dd HH:mm:ss} m n

The above configuration description, the appender named lemmaXml, forms a log file every day, and the name of the log file is

${catalina.home} / logs/lemmaXml.log

The format of the log is

5p% d {yyyy-MM-dd HH:mm:ss}% m% N2. The second way (this way is correct)

Define the logger variable in the class object as follows

Import org.apache.log4j.Logger;private static Logger logger = Logger.getLogger (ExportLemmaManagerService.class)

That is, to obtain the logger variable through the parameters of the class, it is necessary to have the output configuration of the object log file in the log4j.properties file. Of course, the configuration here is not specifically configured for each class, but for a path as a whole, that is, you can configure the file names of the output files of all classes in a directory, as follows

Log4j.rootLogger=info,stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.Threshold=DEBUGlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%5p d {yyyy-MM-dd HH:mm:ss} c m n log4j.logger.com.soso.baike.service=DEBUG ServiceLoglog4j.appender.ServiceLog=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.ServiceLog.Threshold=DEBUGlog4j.appender.ServiceLog.File=$ {catalina.home} / logs/service.loglog4j.appender.ServiceLog.MaxBackupIndex=10log4j.appender.ServiceLog.layout=org.apache.log4j.PatternLayoutlog4j.appender.ServiceLog.layout.ConversionPattern=%5p d {yyyy-MM-dd HH:mm:ss} c m n

The output file method under the directory com.soso.baike.service is configured above, and the above ExportLemmaManagerService class is under this package, so if you use the class method under this package to define logger, the output files are all in the service.log file, and a new log file is generated every day.

How to customize the log4j output format at will

In some cases, we need to customize the output format of log4j without affecting the original code.

For example, such requirements rigidly specify the log format of the project as follows:

Date log level ClassName:line-[version number] [request ip address] [project application name] [service interface module] [module method] [business parameter 1] [business parameter 2] [business parameter 3] log details (must be in json format)

Example:

2018-05-10 14 OrderController 04V 50972 INFO ViolationService:51-[v1.0.0] [192.168.137.47] [merchant-service.cx580.com] [OrderController] [messageList] [null] [] {"body": "order status message list resp: {\" code\ ": 1000,\" msg\ ":\" success\ "}

Where:

The version number refers to the actual version information of the current service interface, such as V1.0.1

The request ip address is the real request ip of the user.

Project application name is the name or identity of the project, for example, the payment service definition application name is payService

Service interface module refers to the module code corresponding to the request interface. For example, if the request order interface is used, the interface module is OrderControlller.

Module method refers to the request method corresponding to the API. For example, the module method corresponding to the order-issuing API is createOrder.

Business parameter 1 can write the corresponding business data according to the actual situation and enter the order number orderId. This parameter can be empty.

Business parameter 2 same as above

Business parameter 3 same as above

Log details refer to the description information that needs to be printed when the API is requested. For example, when an order exception is created, the exception details are described in the exception capture method body, and the log content needs to be defined in a json structure.

The above is the scenario I encountered. Without affecting the original project code, we adjust the log format and use the following solution:

1. The substitution variable is populated at the beginning of the request thread using the AOP section through the placeholder substitution% X {} of log4j with MDC formatting the log

two。 Inherit the concrete appender class of log4j, override the subAppend method, and modify the content format of the log output.

At this point the log4j file is as follows

Log4j.rootCategory=INFO, stdout, file, errorfile#log4j.category.com.cx=DEBUGlog4j.logger.error=errorfile log4j.appender.stdout=com.test.common.GrayLogConsoleAppenderlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%d {yyyy-MM-dd HH:mm:ss SSS}% 5p% c {1}:% L% X {log_version}% X {log_ip}% X {log_item}% X {log_module}% X {log_method}% X {log_req_params}% m% n log4j.appender.file=com.test.common.GrayLogDailyRollingFileAppenderlog4j.appender.file.file=$ {log.dir} / ${spring.application.name} .log4j.logder.file.DatePattern ='. 'yyyy-MM-ddlog4j.appender.file.layout=org.apache.log4j. PatternLayoutlog4j.appender.file.layout.ConversionPattern=%d {yyyy-MM-dd HH:mm:ss SSS}% 5p% c {1}:% L% X {log_version}% X {log_ip}% X {log_item}% X {log_module}% X {log_method}% X {log_req_params}% m% n log4j.appender.errorfile=com.test.common.GrayLogDailyRollingFileAppenderlog4j.appender.errorfile.file=$ {log.dir} / ${spring.application.name} _ error.loglog4j.appender.errorfile.DatePattern='.'yyyy-MM-ddlog4j.appender.errorfile.Threshold = ERRORlog4j. Appender.errorfile.layout=org.apache.log4j.PatternLayoutlog4j.appender.errorfile.layout.ConversionPattern=%d {yyyy-MM-dd HH:mm:ss SSS}% 5p% c {1}:% L% X {log_version}% X {log_ip}% X {log_item}% X {log_module}% X {log_method}% X {log_req_params}% m% n

In the log4j.properties file, we made two changes, one was to add the variable% X {value}, and the other was to change the original DailyRollingFileAppender to com.test.common.GrayLogConsoleAppender.

Handle the variable of log4j, controller the code, and put the thread variable in the entry of a http request java, which takes effect during the life cycle of the current http request.

The section code is as follows:

@ Around ("execution (public * com.test.controller..*.* (..)") Public Object aroundController (ProceedingJoinPoint joinPoint) {ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes (); HttpServletRequest request = attributes.getRequest (); String execIp= request.getHeader ("X-Real-IP"); if (StringUtils.isBlank (execIp)) {execIp=request.getRemoteAddr ();} String execClass= joinPoint.getTarget (). GetClass (). GetSimpleName (); String execMethod = joinPoint.getSignature (). GetName () Map map = request.getParameterMap (); List paramsList = new ArrayList (); for (Map.Entry m: map.entrySet ()) {String [] value = m.getValue (); paramsList.add (m.getKey () + "=" + StringUtils.join (value, ","));} String execParams = "[" + StringUtils.join (paramsList, "&") + "] []" MDC.put ("log_version", "- [V1.0.0]"); MDC.put ("log_item", "[violation-mini]"); MDC.put ("log_module", "[" + execClass + "]"); MDC.put ("log_method", "[" + execMethod+ "]"); MDC.put ("log_req_params", "" + execParams) MDC.put ("log_ip", "[" + execIp+ "]"); Object result= null; try {result= joinPoint.proceed ();} catch (Throwable throwable) {LOGGER.error ("method exception:", throwable);} return result;}

At this point, all the MDC variables in the format have been placed successfully.

Next, put the original log content on the json jacket.

The new GrayLogConsoleAppender class inherits the concrete appender class

The code is as follows:

Package com.test.common; import net.sf.json.JSONObject;import org.apache.commons.lang.StringUtils;import org.apache.log4j.ConsoleAppender;import org.apache.log4j.spi.LoggingEvent;import org.apache.log4j.spi.ThrowableInformation; import java.lang.reflect.Field / * * @ Author: Lxx * @ Description: * @ Date: Created in 17:29 2018-5-30 * / public class GrayLogConsoleAppender extends ConsoleAppender {@ Override protected void subAppend (LoggingEvent event) {try {Class clazz = LoggingEvent.class; Field filed = clazz.getDeclaredField ("throwableInfo"); filed.setAccessible (true); Object exception = filed.get (event) JSONObject json = new JSONObject (); if (exception! = null) {if (exception instanceof ThrowableInformation) {ThrowableInformation throwableInformation = (ThrowableInformation) exception; String [] details = throwableInformation.getThrowableStrRep (); String error_msg = StringUtils.join (details, "\ r\ n") Json.put ("exception", error_msg);}} filed.set (event,null); boolean flag = false; Field filed1 = clazz.getDeclaredField ("message"); filed1.setAccessible (true); Object message = filed1.get (event) If (message instanceof String) {String msg = (String) message; if (message! = null) {flag = true;} json.put ("body", msg); filed1.set (event, json.toString ()) } if (! flag) {Field filed2 = clazz.getDeclaredField ("renderedMessage"); filed2.setAccessible (true); Object message2 = filed2.get (event); if (message2 instanceof String) {String msg = (String) message2; json.put ("body", msg) Filed2.set (event, json.toString ());} catch (Exception e) {e.printStackTrace ();} super.subAppend (event);}}

So far, the log content has been covered with a json coat, and when there is an exception log, the stack information of the exception will be put into the exception of json and output, and the stack information will not be printed.

End result:

2018-06-09 00 INFO LogAspect:65-[V1.0.0] [223.88.53.135] [violation-mini] [TestController] [queryList] [appName=abc&authType=test&avatar=&nickName=&token=asdfasdfadsfasdf&userId=asdfasdfasdfasdf&userType=aaaaa] [] {"body": "result: ResponseResult {code='0', msg='null', errormsg=' query succeeded', data= {}, successFlag=false}"}

The above is all the contents of the article "how log4j controls the log output file name". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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