'Logging/Log4j'에 해당되는 글 4건

How to use the log4j

1. properties

1_1 properties

1_2. java

2. XML

Configuration

It explains how you can configure the core components using a configuration file

Configuring log4j involves assigning the Level, defining Appender, and specifying Layout objects in a configuration file

1. log4j.properties

By default, the LogManager looks for a file named log4j.properties in the CLASSPATH

- The level of the root logger is defined as DEBUG. The DEBUG attaches the appender named X to it

- set the appender named X to be a valid appender

- Set the layout for the appender x

2. Debug Level

TRACE < DEBUG < INFO < WARN < ERROR < FATAL < ALL

3. Appenders

Apache log4j provides Appender objects which are primarily responsible for printing logging messages to different destinations

Each Appender object has different properties associated with it

3_1. properties set

 log4j.logger.[logger-name]=level, appender1, appender..n

 ex) log4j.appender.console = org.apache.log4j.ConsoleAppender

3_2. XML

3_3. Appender

- ConsoleAppender :  output log data on the console

- FileAppender : log message is written on the file

- RollingFileAppender : The log message is written to a file and If File size is full, It makes a new file

- DailyRollingFileAppender : log message is written to a file and It makes a new file each day

- SMTPAppender : Send log message by using email

4. Layout

DateLayout : Record the log data by its creation time

HTMLLayout : Record the log data of HTML form

Install and Architecture

1. Install 

- http://logging.apache.org/log4j/1.2/download.html 

- To unzip the file and add a lib to java

2. Architecture

2_1. Core objects

- These are mandatory objects of the framework. They are required to use the framework

2_2. Support objects

- These are optional objects of the framework. They support core objects to perform additional but important tasks

3. Core Objects

3_1 . Logger Object

- The top-level layer is the Logger which provide the Logger object.

- The Logger object is responsible for capturing logging information and they are stored in a namespace hierarchy

3_2. Layout Object

- The layout layer provides objects which are used to format logging information in different styles

- It provides support to appender objects before publishing logging information

3_3. Appender Object

- This is a lower-level layer which provides Appender objects. The Appender object is responsible for publishing logging information to various preferred destinations such as a database, file, consol..

Define

log4j is a reliable, fast and flexible logging framework written in Java, which is distributed under the Apache Software License

log4j has been ported to the C, C++, C# Perl, Python, Ruby...

1. Main components

- loggers : Responsible for capturing logging information

- appenders : Responsible for publishing logging information to various preferred destinations

- layouts : Responsible for formatting logging information in different styles