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;
}
}
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="$${ctx:threadId}">
<Route>
<RollingFile name="RollingFile-${ctx:threadId}" fileName="${logDir}/last-${ctx:threadId}.log" filePattern="${logDir}/%d{yyyy-MM-dd}/archived_%d{HH-mm}-${ctx:threadId}.log">
<PatternLayout pattern="${logMsgPattern}"/>
<Policies>
<OnStartupTriggeringPolicy />
</Policies>
</RollingFile>
</Route>
</Routes>
</Routing>
</appenders>
<loggers>
<root level="debug">
<appender-ref ref="Console" level="debug" />
<appender-ref ref="Routing" level="debug"/>
</root>
</loggers>
</configuration>
The key 'threadId' [used in <Routes pattern="$${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;
来源：https://stackoverflow.com/questions/17191401/using-different-log-files-for-every-thread-created