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How to modify selected log messages to print to a different log file?

I use log4j to print messages to log files in my Java project.
My current log file is set to log.INFO level and this builds a log file called logFile1.log
I want to print the same set of messages to a different log file (logFile2.log), with a selected number of messages slightly modified.
Code eg:
log.info("Customer created");
log.info("Customer name:" +customerName);
<instead of the above log message, here I want to print "ABC" in logFile2.log>
log.info("Phone number added");
log.info("Phone number:" +phoneNumber);
<instead of the above log message, here I want to print "DEF" in logFile2.log>
Here is how logFile1.log would look:
Customer created
Customer name:Bob
Phone number added
Phone number:123-456-7890
Here is how I want my logFile2.log to look like:
Customer created
ABC
Phone number added
DEF
What is the most efficient way to achieve this?

There are a couple of ways to handle this that I can think of. Both assume you are using a PatternLayout of Log4j2.
The first option is to use replace attribute of the PatternLayout. However, I am not aware that it is possible to replace multiple strings with different values from a single regex. This is more useful if you are trying to mask certain fields and replace them all with "****" or similar.
The second option would be to use a PatternSelector. In this option you would either use the ScriptPatternSelector or create a custom PatternSelector to compare the message text and choose the pattern to use. This would look like:
<PatternLayout>
<ScriptPatternSelector defaultPattern="%m%n">
<Script name="BeanShellSelector" language="bsh"><![CDATA[
if (logEvent.getMessage() != null) {
String msg = logEvent.getMessage().getFormattedMessage();
if (msg.startsWith("Customer name:")) {
return "CustomerName";
} else if (msg.startsWith("Phone number:")) {
return "PhoneNumber";
}
return null;
} else {
return null;
}]]>
</Script>
<PatternMatch key="CustomerName" pattern="ABC%n"/>
<PatternMatch key="PhoneNumber" pattern="DEF%n"/>
</ScriptPatternSelector>
</PatternLayout>

log4j.logger.logFile1 =DEBUG, file1Appender
log4j.logger.logFile2= DEBUG, file2Appender
log4j.additivity.logFile1=false
log4j.additivity.logFile2=false
log4j.appender.file1Appender=org.apache.log4j.RollingFileAppender
log4j.appender.file1Appender.File=<path>/logFile1.log
log4j.appender.file1Appender.MaxFileSize=1MB
log4j.appender.file1Appender.MaxBackupIndex=1
log4j.appender.file1Appender.layout=org.apache.log4j.PatternLayout
log4j.appender.file1Appender.layout.ConversionPattern=<specify your pattern>
log4j.appender.file2Appender=org.apache.log4j.RollingFileAppender
log4j.appender.file2Appender.File=<path>/logFile2.log
log4j.appender.file2Appender.MaxFileSize=1MB
log4j.appender.file2Appender.MaxBackupIndex=1
log4j.appender.file2Appender.layout=org.apache.log4j.PatternLayout
log4j.appender.file2Appender.layout.ConversionPattern=<specify your pattern>
And then you can log to different logger the messages? Have your own extended appender and modify the message before raising the event

Dropwizard default logback pattern

Does anyone knows the default format pattern for Dropwizard 0.7.1 logging, if no logFormat is configured?
I need sth like:
%d{HH:mm:ss.SSS} %-5level [%X{id}] [%X{format}] [%thread]: %class{0}::%method:%line - %msg%n

Logback uses implementations of the Layout interface's doLayout() method to translate logging events to Strings that can be output, as outlined in the documentation. Dropwizard provides an extension to the PatternLayout class (which is in turn an extension of the abstract PatternLayoutBase class):
PatternLayout takes a logging event and returns a String. However,
this String can be customized by tweaking PatternLayout's conversion
pattern.
public class DropwizardLayout extends PatternLayout {
public DropwizardLayout(LoggerContext context, TimeZone timeZone) {
super();
setOutputPatternAsHeader(false);
getDefaultConverterMap().put("ex", PrefixedThrowableProxyConverter.class.getName());
getDefaultConverterMap().put("xEx", PrefixedExtendedThrowableProxyConverter.class.getName());
getDefaultConverterMap().put("rEx", PrefixedRootCauseFirstThrowableProxyConverter.class.getName());
setPattern("%-5p [%d{ISO8601," + timeZone.getID() + "}] %c: %m%n%rEx");
setContext(context);
}
}
What this does is:
Ensures that outputPatternAsHeader is disabled, which is a flag that outputs the String pattern that you want at the top of any logs. One way to confirm the pattern used could be to enable this flag on your appender, as outlined in the logback documentation.
Overrides a number of conversion words related to printing exceptions to use an implementation of ThrowableProxyConverter that prefixes the stack trace with exclamation marks.
Set the pattern to be "%-5p [%d{ISO8601," + timeZone.getID() + "}] %c: %m%n%rEx", using the timezone passed in. If you don't add the timezone information explicitly, logback will use the JVM's timezone, or else GMT. If this is acceptable, you could just use %d, as the ISO8601 format is the default.
Sets the context.

Eclipse console link, duplicate filenames in package structure, which is opened?

I have an application that has two classes called "Service" in two different places in the package structure. The logging outputs the file and line number like this, eg: (Service.java:102)
This becomes a clickable link in the console output in Eclipse. Normally, these links are great because you can find exactly of where the output was printed from with a single click.
But now I have two Service.java files, doing two entirely different things, and they're in a different place in the package structure. I can't rename either of them.
When I click on the link, it takes me to the wrong java file, even when the correct java file is open in the editor.
I've searched around, but I can't find the answer. Is there a way to tell Eclipse which java file to consider first? Or a way to tell which package to look in first? Something, anything, to make these clickable links useful again?

I guess your logger is configured like this to ouput a log like that (Service.java:102) :
(%F:%L)
%F : Used to output the file name where the logging request was issued.
%L : Used to output the line number from where the logging request was issued.
Try to used %l instead
%l : Used to output location information of the caller which generated the logging event.
EDIT
this solution does not seem to work well, it prints
com.x.y.z.MyClass.myMethod(MyClass.java:36)
=> the link is only on the classname, same issue.
But using the following pattern will work
(%C.java:%L)
It will print a full link like this :
(com.x.y.z.MyClass.java:36)

i know three ways how to print a clickable class link in the console output.
First way:
Just print the class name inside the parentheses: System.out.println("(Service.java:42)");
This is simple method and will work if you are not using ambiguous class names. Since Eclipse console does not have informations required to decide which file should be opened, i guess it will open the first occurence.
Second way:
In your case. I would do it by using StackTraceElement to print the class name.
That way:
StackTraceElement element = new StackTraceElement(
"Service", // Class name
"myFunnyMethodName", // Method name
Service.class.getName()+".java", // Path to File
2); // line number
System.out.println(element);
Third way:
If you don't want to create StackTraceElement you can get it from you current thread.
Example:
System.out.println(Thread.currentThread().getStackTrace()[1]);
EDIT:
The other option is to try the Grep Console Plugin for Eclipse. You can define your own Expressions with Link, Color, Popup etc...

Formatting slf4j to log message types with colors

I am using slf4j for logging in my Java Application. It involves a lot logging and log monitoring.
Sometimes it is really difficult to read and find information from logs when the entire log is printed in the black color with.
Just to make it more readable, is it possible to log the different kinds of messages in different colors?
For example all Error level messages in Red color or a different font size and all Info level messages in blue color and a different font size.
Any suggestions or help is welcome.
Thnx.

It's not possible to change colors of slf4j logging, because there are no formatters. SLF4J is a middleware between your application and some logging facility, for example, Log4j or Logback.
You can change colors in Log4j output, as explained here. I would recommend to use MulticolorLayout from jcabi-log

Something you have to bear in mind.
First, SLF4J is only a logging facade. How the actual log message is handled depends on the binding it used. Therefore your question is invalid, instead, you should quote which implementation you want to use (LogBack? Log4J? etc)
Second, "Coloring" is not something meaningful in most case. For example, if you are referring a plain text log file, there is nothing that we can control the coloring because they are all plain text (unless your editor have special syntax highlighting built-in for your log message format). It may be meaningful if you want to see the color in the console/terminal, or if you are outputting your log into file format that allow you to contain color information (e.g. HTML).
With these two idea in mind, here is my suggestion.
LogBack has built-in support for coloring http://logback.qos.ch/manual/layouts.html#coloring in console output. If you are looking for way to see color in console output, and you are allowed to use LogBack, this is what you are looking for.

Two solutions come to my mind. They are not colors, but alternative solutions:
In your File Appender configuration, you can configure the pattern to include the log level (error, warn, etc). Then you can grep the file, to filter messages by level.
You can configure two file appenders (for two separate log files) with different level threshold. For instance, one would log all the logs above debug level (so info, warn, error) into let's say logs.txt and the other would log only the errors logs into errors.txt
Hope it helps.

Add next appender into logback.xml to colorize logs output:
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<!-- encoders are assigned the type
ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
<encoder>
<Pattern>%d %highlight(%-5level) [%thread] %cyan(%logger{15}): %msg%n</Pattern>
</encoder>
</appender>

In addition to using a colored ConsoleAppender, you could also color the statement itself. Note this has limitations and may not work with all systems. It worked well for internal projects, particularly when you want to log that a major task in a chain is complete or simply while debugging errors.
To quote an external link:
System.out.println("\u001B[31m" + "the text is red" + "\u001B[0m");
\u001B[31m is the ANSI code to color the output red and \u001B[31m is the ANSI reset command.
public class ColorLogger {
private static final Logger LOGGER = LoggerFactory.getLogger(ColorLogger.class);
public void logDebug(String logging) {
LOGGER.debug("\u001B[34m" + logging + "\u001B[0m");
}
public void logInfo(String logging) {
LOGGER.info("\u001B[32m" + logging + "\u001B[0m");
}
public void logError(String logging) {
LOGGER.error("\u001B[31m" + logging + "\u001B[0m");
}
}
In your case, it sounds like you can try to write the contents of the aggregated log out and optionally color each statement by finding each string that concerns you.
This can alternatively just be done by printing it to an HTML page and using CSS selectively on your text.

I use filters for both logging level and package. This example comes from Spring boot application.properties
logging.level.root=warn
logging.level.org.springframework=warn
logging.level.org.hibernate=warn
logging.level.org.starmonkey.brown=DEBUG
This way I see only messages I want to see

Best technique to print text to console

I am writing a command line tool that performs a number of tests to our servers and reports an output to screen.
I am currently using log4j to print to screen and to a log file.
However, I was wondering if there was a better technique to manage all the printing from one class instead of having the "print" commands scattered all over my code.
e.g.
logger.info("Connecting to environment: " + envName);
if (cmd.hasOption(OPTION_CHECK_PRIMARY)) {
//print primary leg
String primaryLegName = env.getPrimaryLeg().getLegName();
String message = "is primary";
logger.info(String.format("%s : %-4s %s", envName, primaryLegName, message));
}
This is an example of the output that is now scattered across all my code.
Would it be best to have a Formatter class that handles all the printing?
What is the best approach to create it?
What do you think about something like:
Formatter pf = new PlainFormatter();
...
pf.printEnvironment(envName);
if (cmd.hasOption(OPTION_CHECK_PRIMARY)) {
//print primary leg
String primaryLegName = env.getPrimaryLeg().getLegName();
pf.printPrimary(envName, primaryLegName);
}

Have you tried using log4j.properties to format the text. I think if you are trying to format uniquely for each class, then this is still possible using log4j.properties.
Here is a simple example of log4j.properties
log4j.rootLogger=INFO, A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
You can use Pattern in properties like so:
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n

log4j has appenders to redirect log messages to different locations. quote" Multiple appenders exist for the console, files, GUI components, remote socket servers, JMS, NT Event Loggers, and remote UNIX Syslog daemons "unquote