Simply talk about the use of log4j

Import log4j-1.2.17.jar package in the Java project

Code import org.apache.log4j.Logger;

private static final Logger log = Logger.getLogger(className.class);

className is the current class name

The configuration of the log4j.properties file is as follows:

Set up

log4j.rootLogger = debug,stdout,D,E

Output information to the control lift

log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n

Output logs above DEBUG level to =E://logs/log.log

log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = E://logs/log.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = DEBUG
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n

Output logs above ERROR level to =E://logs/error.log

log4j.appender.E = org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.File =E://logs/error.log
log4j.appender.E.Append = true
log4j.appender.E.Threshold = ERROR
log4j.appender.E.layout = org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n

The above is the content of the file, this file needs to be placed in the src folder! ! !

Once configured, you can use log.info("Hello");
log.error(e1.toString()); to
record information