Using different Log files for every thread created

问题:

I am working on logging with log4j, i have sample code which creats certain number of threads , i want to use different log files for each threads. so I have use the PropertyConfigurator.configure() which takes a property object.

I have configured the property object in my code i.e hardcoded , but I want to load it external to code.

Now I want to provide all the configurations externally through a property file i.e not to hardcode them in code and at runtime add the two properties -

props.setProperty("log4j.logger."+"Thread" +         Thread.currentThread().getName(),"DEBUG, file"); 

and

props.setProperty("log4j.appender.file.File",         "/home/ekhaavi/workspace/TEST_2/ThreadHandler"+                 Thread.currentThread().getName()+".log");  

since these variables like Thread.currentThread().getName() will get evaluated at runtime.

can anyone suggest me how to do it

I have three class --> MainClass, Parser(Thread class), LoggerClass in package

import java.util.HashMap; import java.util.Map;  public class MainClass { private static final org.apache.log4j.Logger log = LoggerClass.getLogger(MainClass.class);  public static void main(String args[]){     Map map = new HashMap();     map.put("Subject", "Math");      log.info("The value of the map is " + map.toString());     for(int ii=0; ii< 3; ii++){          Parser th = new Parser(ii);        }     } } 

---

package com.test.log4j.conf;   public class Parser implements Runnable{  private org.apache.log4j.Logger log;  Parser(){     Thread th = new Thread(this);     th.start();  }   @Override public void run() {      log = LoggerClass.getThreadLogger("Thread" + Thread.currentThread().getName());     log.info("------dagdjlagdjgasdjljgljg");     System.out.println("The thread is " + Thread.currentThread().getName()); }  } 

---

and finally my logger class is -->

import java.util.Properties; import org.apache.log4j.Logger; import org.apache.log4j.PropertyConfigurator;  public abstract class LoggerClass {  public static Logger getLogger(Class clazz){      org.apache.log4j.Logger log = Logger.getLogger(clazz);     Properties props=new Properties();     props.setProperty("log4j.appender.file","org.apache.log4j.RollingFileAppender");      props.setProperty("log4j.appender.logfile","org.apache.log4j.DailyRollingFileAppender");     props.setProperty("log4j.appender.logfile.DatePattern","'.'yyyy-MM-dd");     props.setProperty("log4j.appender.logfile.layout","org.apache.log4j.PatternLayout");     props.setProperty("log4j.appender.logfile.layout.ConversionPattern","%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n");     props.setProperty("log4j.appender.logfile.File","/home/ekhaavi/workspace/TEST_2/mylogfile.log");     props.setProperty("log4j.logger.com.com.test.log4j.conf","INFO, logfile");      PropertyConfigurator.configure(props);     return log;  }  public static Logger getThreadLogger(String str){      org.apache.log4j.Logger log = Logger.getLogger(str);     Properties props=new Properties();     props.setProperty("log4j.appender.file","org.apache.log4j.DailyRollingFileAppender");     props.setProperty("log4j.appender.file.DatePattern","'.'yyyy-MM-dd");     props.setProperty("log4j.appender.file.layout","org.apache.log4j.PatternLayout");     props.setProperty("log4j.appender.file.File","/home/ekhaavi/workspace/TEST_2/ThreadHandler"+Thread.currentThread().getName()+".log");     props.setProperty("log4j.appender.file.layout.ConversionPattern","%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n");     props.setProperty("log4j.logger."+"Thread" + Thread.currentThread().getName(),"DEBUG, file");      PropertyConfigurator.configure(props);     return log;   }   } 

回答1:

For log4j v2 you can use RoutingAppender to dynamically route messages. You can put value for key 'threadId' into the ThreadContext map and then use this id as a part of file name. There is an example which I have easily applied for the same purpose as yours. See http://logging.apache.org/log4j/2.x/faq.html#separate_log_files

Be aware when putting values into ThradContext map: "A child thread automatically inherits a copy of the mapped diagnostic context of its parent." So if you have put a value for key 'threadId' into the parent thread and eventually created multiple threads from it, then all child threads will inherit the value of 'threadId' value. I was no able to simply override this value by using put() one more time - you need to use ThreadContext.clear() or explicitly remove() the value from thread context map.

Here is my working log4j.xml:

<?xml version="1.0" encoding="UTF-8"?> <configuration status="WARN">     <properties>             <property name="logMsgPattern">%d{HH:mm:ss} %-5level - %msg%n</property>             <property name="logDir">test logs</property><!-- ${sys:testLogDir} -->     </properties>     <appenders>         <Console name="Console" target="SYSTEM_OUT">                             <PatternLayout pattern="${logMsgPattern}"/>         </Console>          <Routing name="Routing">                     <Routes pattern="$${ctx:threadId}">                                      <Route>                             <RollingFile name="RollingFile-${ctx:threadId}" fileName="${logDir}/last-${ctx:threadId}.log" filePattern="${logDir}/%d{yyyy-MM-dd}/archived_%d{HH-mm}-${ctx:threadId}.log">                                     <PatternLayout pattern="${logMsgPattern}"/>                                     <Policies>                                 <OnStartupTriggeringPolicy />                             </Policies>                      </RollingFile>                         </Route>                     </Routes>             </Routing>           </appenders>          <loggers>                            <root level="debug">                 <appender-ref ref="Console" level="debug" />                 <appender-ref ref="Routing" level="debug"/>             </root>                              </loggers>   </configuration> 

回答2:

The key 'threadId' [used in <Routes pattern="$${ctx:threadId}"> ] must be added to the thread context map in the run() method of the Runnable class as follows,

public class SomeClass implements Runnable{   private int threadID;   public SomeClass(int threadID){    this.threadID=threadID;    }  @Override  public void run() {      ThreadContext.put("threadId", threadID);     //Some code     ThreadContext.remove("threadId");    } } 

In addition, the correct log4j packages must be imported, as shown below.

import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.apache.logging.log4j.ThreadContext; 

Please note that the following imports will not work. LogManager and Logger must also come from org.apache.logging.log4j.

import org.apache.log4j.LogManager; import org.apache.log4j.Logger; import org.apache.logging.log4j.ThreadContext; 

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