Dec 31, 2009 I can’t find many log4j.properties examples, here are a few log4j.properties examples that are used in my project, just for sharing. # Root logger option log4j.rootLogger=INFO, file # Direct log messages to a log file log4j.appender.file=org.apache.log4j.RollingFileAppender #Redirect to Tomcat.
- Setting the log4j.defaultInitOverride system property to any other value then 'false' will cause log4j to skip the default initialization procedure (this procedure). Set the resource string variable to the value of the log4j.configuration system property.
- The log4j API provides the org.apache.log4j.jdbc.JDBCAppender object, which can put logging information in a specified database. BufferSize Sets the buffer size. Default size is 1. Driver Sets the driver class to the specified string. If no driver class is specified, it defaults to sun.jdbc.odbc.
The latest version log4j-core can be found here. Custom Appender. There are two ways by which we can implement our custom appender. First is by implementing the Appender interface and the second is by extending the AbstractAppender class. The second method provides a simple way to implement our own custom appender and that is what we will use. Log4J default parameters. When Tivoli® Directory Integrator is installed, a FileAppender is used for the default logger. If you want to change the default logger you must change the content of the log4j.properties file situated in the TDIinstalldir/etc folder. If you want to generate your logging information in a particular format based on a pattern, then you can use org.apache.log4j.PatternLayout to format your logging information. The PatternLayout class extends the abstract org.apache.log4j.Layout class and overrides the format method to structure.
Active4 months ago
Hi All I have a log4j properties something like the below. Everything that is logged in TextProcessor.log is something is above above WARN level. I don't understand the threshold that is set here to debug. Can someone explain what the threshold does
Thanks in advance
Mridang Agarwalla18.1k5555 gold badges180180 silver badges333333 bronze badges
javanerdjavanerd1,23244 gold badges1818 silver badges3030 bronze badges
4 Answers
You have two things here : a logger, and an appender. Unfortunately, you chose the same name for both, which doesn't make it very clear.
The logger's minimum level is set to warn, which means everything you log with this logger which doesn't have at least the warn level will be ignored.
Once a message is accepted by the logger, it's sent to one or several appenders (to a file, to the console, to a mail server, etc.). Each of these appenders may define a threshold. You could for example limit the messages in the console to errors, but accept warn messages in the log file.
JB NizetJB Nizet571k6969 gold badges956956 silver badges10621062 bronze badges
Threshold is second filter for messages to be logged
e.g.:
if Logger is set at level DEBUG and appender Threshold is set at Error then with the appender TextProcessor only Error and higher severity messages would be logged.
Log4j Logger Appender
Use of Threshold is ,you can define different appender with different threshold levels ,for e.g in above mentioned example you can also have InfoLogger with Info level messages logging enabled
To understand levels , There are below levels of logging in log4j:
go to URL for more details
Shirishkumar BariShirishkumar Bari
The levels of logging are
cweiskeTRACE
, DEBUG
, INFO
, WARN
, ERROR
and FATAL
. You will be able to choose what to log at what level in the code depending on the severity. For example you will have the ability to log entry and exit of methods but can choose to log at the DEBUG
level. This will help you to debug the code as by default it will print out on the console (default console appender is on). While going to production you can increase the threshold to ERROR
and prevent the application from printing out not so useful details on the console or log files.24.1k1111 gold badges9797 silver badges162162 bronze badges
Vinod RVinod R
Give you simple mapping from properties config file to flow of log messages. (I hid some lines of config to minimize)
To understand what it is, you should know that:
- The levels of logging increase when retrieving to the leftmost: TRACE, DEBUG, INFO, WARN, ERROR and FATAL
- Minimum level logging which logger accepts from application.
- Minimum level logging on appender which decides what will be written
** There are some thing more complex about inheritance and additivity, but you should start at basic and simple things first.
Ken BlockKen Block2,92511 gold badge1616 silver badges2121 bronze badges
Not the answer you're looking for? Browse other questions tagged javalogginglog4j or ask your own question.
Active2 years, 7 months ago
My story:
I want to make a thing which is as simple as a simplest possible log4j logger that logs rows to a file. I have found several examples with some functionality, but not a basic, general one that really works, and not one with an explanation how the each row work.
Question:
Could anybody provide one?
Prerequisites:
- I already know where to put the file and I have the log4j configured and working for console logging.
- Now I want to log to a file and also find the file from file system once the program has run.
- Rows needed to be added to the existing
log4j.properties
file are the desired output.
mico
micomico6,8791212 gold badges4949 silver badges8686 bronze badges
4 Answers
I have one generic log4j.xml file for you:
with one console, two file appender and one logger poiting to the second file appender instead of the first.
EDIT
In one of the older projects I have found a simple log4j.properties file:
For the description of all the layout arguments look here: log4j PatternLayout arguments
Matthias Braun16.2k1212 gold badges8989 silver badges125125 bronze badges
Tomasz StanczakTomasz Stanczak10.7k11 gold badge2626 silver badges3131 bronze badges
Log4j can be a bit confusing. So lets try to understand what is going on in this file:In log4j you have two basic constructs appenders and loggers.
Appenders define how and where things are appended. Will it be logged to a file, to the console, to a database, etc.? In this case you are specifying that log statements directed to fileAppender will be put in the file
sample.log
using the pattern specified in the layout tags. You could just as easily create a appender for the console or the database. Where the console appender would specify things like the layout on the screen and the database appender would have connection details and table names. Loggers respond to logging events as they bubble up. If an event catches the interest of a specific logger it will invoke its attached appenders. In the example below you have only one logger the root logger - which responds to all logging events by default. In addition to the root logger you can specify more specific loggers that respond to events from specific packages. These loggers can have their own appenders specified using the
appender-ref
tags or will otherwise inherit the appenders from the root logger. Using more specific loggers allows you to fine tune the logging level on specific packages or to direct certain packages to other appenders.So what this file is saying is:
- Create a fileAppender that logs tofile sample.log
- Attach that appender to the rootlogger.
- The root logger will respond to anyevents at least as detailed as'debug' level
- The appender is configured to onlylog events that are at least asdetailed as 'info'
The net out is that if you have a
logger.debug('blah blah')
in your code it will get ignored. A logger.info('Blah blah');
will output to sample.log.The snippet below could be added to the file above with the log4j tags. This logger would inherit the appenders from
nsfyn55nsfyn55<root>
but would limit the all logging events from the package org.springframework
to those logged at level info
or above.10.4k55 gold badges3939 silver badges7575 bronze badges
Here's a simple one that I often use:
The format of the log is as follows:
Such a format is defined by the string
%5pt[%d] [%t] (%F:%L)n t%m%nn
. You can read the meaning of conversion characters in log4j javadoc for PatternLayout
.Included comments should help in understanding what it does. Further notes:
- it logs both to console and to file; in this case the file is named
owls_conditions.log
: change it according to your needs; - files are rotated when they reach 10000KB, and one back-up file is kept
11.6k55 gold badges3333 silver badges5959 bronze badges
Here is a log4j.properties file that I've used with great success.
The DailyRollingFileAppender will create new files each day with file names that look like this:
Each entry in the log file will will have this format:
Set the location of the above file by using
-Dlog4j.configuration
, as mentioned in this posting:In your Java code, be sure to set the name of each software component when you instantiate your logger object. I also like to log to both the log file and standard output, so I wrote this small function.
And then call it like so:
Community♦
stackoverflowuser2010stackoverflowuser201015.7k2323 gold badges107107 silver badges143143 bronze badges