Loggerfactory uses log4j Parameter introduction of properties

LoggerFactory Use with log4j.properties Parameter introduction of

One 、LoggerFactory Use
Use org.slf4j To control the output of the log , It is common to use this code

private static final Logger logger = LoggerFactory.getLogger(LoggerFactoryDemo.class);

The dependencies needed are

<!-- slf4j  Dependency package  2021.08.19 -->
    <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.21</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/log4j/log4j -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

If you encounter the following hot spots

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

So it could be slf4j-log4j12 Of scope by test, Need to get rid of scope label
Two 、log4j.properties Parameter Introduction
log4j.properties Need to be in resources Hierarchy creation , If it is placed in the wrong position , There may be the following explosion

log4j:WARN No appenders could be found for logger (com.xxx.xxx.LoggerFactoryDemo).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

Hierarchy demonstration

log4j.properties file

# all: Output all types of information , A: The output mode is console output 
log4j.rootLogger=all, A

#  Console printing 
log4j.appender.A=org.apache.log4j.ConsoleAppender
log4j.appender.A.layout=org.apache.log4j.PatternLayout
log4j.appender.A.layout.ConversionPattern=%d{
    yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n

log4j.appender.B=org.apache.log4j.FileAppender
log4j.appender.B.File=E:\\young\\log.log
log4j.appender.B.layout=org.apache.log4j.SimpleLayout

# html Mode output 
log4j.appender.C=org.apache.log4j.RollingFileAppender
log4j.appender.C.File=E:\\young\\log.html
log4j.appender.C.MaxFileSize=1000KB
log4j.appender.C.MaxBackupIndex=10
log4j.appender.C.layout=org.apache.log4j.HTMLLayout
log4j.appender.C.encoding=gbk

# txt Mode output 
log4j.appender.D=org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File=E:\\young\\log\\log.txt
#log4j.appender.D.File=E:\\hanweb\\log\\log.txt
log4j.appender.D.layout=org.apache.log4j.TTCCLayout

3、 ... and 、Demo
Code

public class LoggerFactoryDemo {
    
    private static final Logger logger = LoggerFactory.getLogger(LoggerFactoryDemo.class);

    public static void main(String[] args) {
    
        logger.info("this is info");
        logger.error("this is error");
        logger.debug("this is debug");
    }
}

ConsoleAppender

2021-08-19 11:21:56 [com.xxx.service.log.LoggerFactoryDemo]-[INFO] this is info
2021-08-19 11:21:56 [com.xxx.service.log.LoggerFactoryDemo]-[ERROR] this is error
2021-08-19 11:21:56 [com.xxx.service.log.LoggerFactoryDemo]-[DEBUG] this is debug