CODEWITHSUNDEEP
javalogging
Ralph
Ralph

Reputation: 4868

Java Logging - how to redirect output to a custom log file for a logger?

I have a question about the jdk logging configuration. I have a EJB (deployed into glassfish) which uses JDK Logging to output messages. Therefor I use a named logger with a code like this:

private static Logger logger = Logger.getLogger("org.imixs.workflow");
.....
       logger.fine(" some info...");
....

I know that I can configure the loglevel for my logger by adding the following line into the logging.properties File from Glassfish:

.....
org.imixs.workflow.level=FINE

But how can I specify the output file for my logger? I would like to put all messages from the logger named 'org.imixs.workflow' into a separate file. Is this possible?

Thanks for any help

Upvotes: 22

Views: 86499

Answers (3)

yair
yair

Reputation: 9245

You should use a FileHandler.

FileHandler fileHandler = new FileHandler("myLogFile");
logger.addHandler(fileHandler);

See Example Depot for some clear examples configuring loggers.

And you might find these answers useful, for setting from properties file.

Upvotes: 13

Ed Bragg
Ed Bragg

Reputation: 108

With java.util.logging, it IS NOT possible simply by modifying the configuration file. Unfortunately, you must extend FileHandler and configure that handler to filter what you want logged.

Upvotes: 6

Peter Szanto
Peter Szanto

Reputation: 7722

the slightly confusing pattern property of FileHandler can be used for this

handlers=java.util.logging.FileHandler
# Default global logging level. 
.level=INFO

#logging level for the foo.bar package
foo.bar.level=CONFIG 
java.util.logging.FileHandler.pattern=%h/java%u.log

A pattern consists of a string that includes the following special components that will be replaced at runtime:

"/" the local pathname separator

"%t" the system temporary directory

"%h" the value of the "user.home" system property

"%g" the generation number to distinguish rotated logs

"%u" a unique number to resolve conflicts

"%%" translates to a single percent sign "%"

If you want to log to multiple files then you can do it by set up multiple handlers for multiple named loggers

#FileHandler for file1    
java.util.logging.FileHandler.pattern = logging_property_test.log
java.util.logging.FileHandler.limit = 50000
java.util.logging.FileHandler.count = 1
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter

#FileHandler for file2
logging.FileHandler2.pattern = logging_property_test2.log
logging.FileHandler2.limit = 50000
FileHandler.count = 1
logging.FileHandler2.formatter = java.util.logging.SimpleFormatter


#setting handler for logger1
logging.PropertyTestingLogger.handlers=java.util.logging.FileHandler

#setting handler for logger2
logging.PropertyTestingLogger2.handlers=logging.FileHandler2

as you can see the trick is that there is a logging.FileHandler2 that is a custom class and does nothing but extends the FileHandler

package logging;

import java.io.IOException;
import java.util.logging.FileHandler;

public class FileHandler2 extends FileHandler {

    public FileHandler2() throws IOException, SecurityException {
        super();
    }

}

Background : unfortunately the creators of Java were not expecting anyone to log into multiple files. If you look at the source of java.util.logging.FileHandler you will find, that the pattern property is loaded by the class name :

public class FileHandler extends StreamHandler {

   private String pattern;

   private void configure() {

        String cname = getClass().getName();
        pattern = manager.getStringProperty(cname + ".pattern", "%h/java%u.log");

Upvotes: 34

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