vijaya
Posts: 3
Nickname: vijaya
Registered: Jan, 2003
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Re: Logfiles
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Posted: Jan 23, 2003 3:39 AM
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Hi!
I got the answer to my qst.
There are three basic approaches I can think of:
(1) Use OS-level output redirection, e.g.
java MyClass 1> output.log 2> error.log
or
java MyClass 1> all_output.log 2>&1
I believe the same syntax works in Unix and Windows here. This is easy,
and requires no changes inside your code.
(2) Use System.setOut() and System.setErr() within your program to
redirect the output to a stream writing to a file, as Layne suggests.
Also pretty easy.
(3) Replace the various println() statements with more advanced logging
techniques, using classes such as those in java.util.logging or the
Log4J package. This is more work than the other two, but may be more
rewarding as it will allow you much more flexibility to make other
adjustments later. E.g. you may initially decide that loggers will
simply write messages to the screen. Later you can easily revise this to
write all messages to one detailed log file, and also write only errors
and important non-error messages to a different file, and also create a
pop-up window to inform the user of errors. (For example.) These later
changes can be made by making changes just to the code that creates and
configures the loggers (or maybe just to configuration files which are
read by your code). Most of the code in the other classes that do the
logging will not need to be changed at all.
I like the third option for a big project, where the power and
flexibility I get later makes it worthwhile to spend a little extra
energy at teh beginning to set up logging. For smaller projects, the
first two options may be appropriate.
Regards.
Vijaya.
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