Apache common logs and log4j logs

Apache common logs and log4j logs

1. Three purposes of the log

A. Monitoring the variables in your code the synchronization of the data is recorded in the file for other system analysis.

B. Tracking code run track, to do after the basis of audit

C. Acting as a debugger in the development environment, output to a file or console

2. Apache provides a common log interface that enables the implementation of the following log implementations for Third-party software common logs:

A. log4j Logger

B. jdk1.4logging

C. simplelog

D. Nooplog

3. Two generic interfaces: Log and Logfactory

In the Eclipse Package Explorer management view, the classes in the Common-logging.jar bundle under the Struts framework:

Two packages: org.apache.commons.logging

Org.apache.commons.logging.impl

Org.apache.commons.logging Log.class Interface

Loglofingurationexception.class

Logfeetoy.class interface

Logsource.class

Package.html

Org.apache.commons.logging.impl Jdk14logger.class

log4j Categorylog.class

Log4factory.class

Log4jogger.class

Logfactoryimpl.class

Logfitlogger.class

Nooplog.class

Simplelog.class

6 levels of common log packs:

Logfactory two static methods

public static Log GetLog (string name) throws by name

Logconfigurationexception;

Public station Log GetLog (class dass) throws by class name

Logconfigurationexceptions

Multiple outputs of log4j: 1. Controller

2. Documents.

3.GUI

4.stocket Interface Server

5.NT Event Recorder

6.Unix Sysleg Daemon Etc Association

Just modify the configuration file.

Set conmmon-logging. Properties

(Special note: An error occurred while upgrading)

Resolved from below

Org.apache.common.logging.log=org.apche.commons.logging.impllog4jlogger

Three important components of log4j:

1. Priority of log information (ERROR.WARN.INFO.DEBUG)

2. The output destination of the log information

3. Output format of log information

LOG4J supports two types of configuration files: xml

Java Property file (key = value)

Log4j.properties Configuration

Htmilayout HTML table

Patternlayout the flexibility to specify layout patterns

Simplelayout contains log information levels and information strings

Ttcclayout contains log generation time, threads, categories, and so on

Similar to printf print format in C language

Print parameters:%m The message specified by the output code

%p Output Priority Debug INFO WARN ERROR FATAL

%r output time in milliseconds to output the log information from the application

The class that the%c output belongs to

%t output The name of the thread that generated the log time

%n output a carriage return line break Windows platform/r/n "UNIX platform"/n/"

%d output point of time, such as%D{YYYMMMDDHH:MM.SS; SSS}

%l output Log information location, class, occurrence of the thread, code location

The call Log log=logfartoty.getlog ("MyTest") in the program;

Log.info ("My Test");

return null

Download log4j 1.2.14 Dist/lib/logging-log4j.jar