Re: Need help logging with java.util.logger
cteb wrote:
Thanks for your help. However, I can't get my Formatter class to run. My
logging properties file is read (I left in an error by mistake and got
error messages on the console). Unfortunately, my formatter is never
used. The regular logging output is sent to the console (stderr instead
of stdout, for some reason; in Eclipse it's red now instead of black).
This is as expected. Why would you expect log messages to go to stdout? stdout
should be used for the output or result of your program.
This is the current state of my properties file:
==
.handlers = java.util.logging.FileHandler, java.util.logging.ConsoleHandler
.level=INFO
java.util.logging.FileHandler.pattern=c:/log.txt
java.util.logging.FileHandler.level=INFO
java.util.logging.FileHandler.formatter=mynamespace.LogFormatter
java.util.logging.ConsoleHandler.level=INFO
java.util.logging.ConsoleHandler.formatter=mynamespace.LogFormatter
==
I'm afraid there was an error in the properties file I posted. .handlers should
be whitespace separated and not comma separated. I don't believe this is causing
your problems though since both the FileHandler and the ConsoleHandler are
created according to your description.
mynamespace.LogFormatter is my formatting class extending
java.util.logging.Formatter. It exists, there is no unnecessary
whitespace in the file (a common mistake I found out searching for
clues). I set a break point in my application in the format(LogRecord)
method which is never reached. I also tried mynamespace.handlers and
mynamespace.level in the properties file, but nothing changes as far as
I can see. My formatter never gets called, neither for my own classes
nor for others.
Is it constructed? Does it have a default constructor? Did you try
java.util.logging.SimpleFormatter instead?
Besides, log.txt is created, contains XML (!) logging information and is
always deleted after the program terminates.
No idea why this is happening. FileHandler typically deletes files only as a
result of file rotation.
I have now spent several hours on this and have almost nothing to show
for it. Really frustrating. Any ideas?
I just looked up how FileHandler obtains the formatter. It calls
LogManager.getFormatterProperty(). This is the code:
Formatter getFormatterProperty(String name, Formatter defaultValue) {
String val = getProperty(name);
try {
if (val != null) {
Class clz = ClassLoader.getSystemClassLoader().loadClass(val);
return (Formatter) clz.newInstance();
}
} catch (Exception ex) {
// We got one of a variety of exceptions in creating the
// class or creating an instance.
// Drop through.
}
// We got an exception. Return the defaultValue.
return defaultValue;
}
Did you see that? See the sophisticated exception handling? Well. I'm stunned.
My wild guess would be that the constructor of your Formatter throws an
exception resulting in an InvocationTargetException or
ExceptionInInitializerError in clz.newInstance(). Try to print something in the
first line of your constructor to stderr to see whether constructor is called at
all.
Otherwise I have no idea so far. Maybe post the code.
BTW, this is a Tomcat application if it makes any difference.
Don't know.
Cheers,
Simon