一.log4j的日志级别

它们定义了日志显示的级别，一共分为五个级别：DEBUG、INFO、WARN、ERROR和FATAL。这五个级别是有顺序的，DEBUG < INFO < WARN < ERROR < FATAL，明白这一点很重要，这里Log4j有一个规则：假设设置了级别为P，如果发生了一个级别Q比P高，则可以启动，否则屏蔽掉。

二.操作案例

2.1 配置pom依赖

    <!-- log4j-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

2.2 配置log4j的配置文件

将log4j.properties文件放到resoureces文件夹下：

内容如下：


######################
## set log levels
######################
log4j.rootLogger=DEBUG,info,CONSOLE,FILEOUT
#DEBUG,CONSOLE,FILE,ROLLING_FILE,MAIL,DATABASE
log4j.addivity.org.apache=true
######################
## CONSOLE Appender ##
######################
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.Threshold=DEBUG
log4j.appender.CONSOLE.Target=System.out
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
#log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n\u00A0
#log4j.appender.CONSOLE.layout.ConversionPattern=[start]%d{DATE}[DATE]%n%p[PRIORITY]%n%x[NDC]%n%t[THREAD] n%c[CATEGORY]%n%m[MESSAGE]%n%n
######################
## Rolling File Appender
######################
log4j.appender.FILEOUT=org.apache.log4j.RollingFileAppender
#log4j.appender.FILEOUT.File=e:/logs/allError333.log
log4j.appender.FILEOUT.File=/logs2/allError333.log
#log4j.appender.FILEOUT.Threshold=ALL
log4j.appender.FILEOUT.Threshold=INFO
log4j.appender.FILEOUT.Append=true
log4j.appender.fileout.MaxFileSize=1000KB
#log4j.appender.ROLLING_FILE.MaxBackupIndex=1
log4j.appender.FILEOUT.layout=org.apache.log4j.PatternLayout
log4j.appender.FILEOUT.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
#log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n\u00A0
#######################
#info log
log4j.logger.info=info
log4j.appender.info=org.apache.log4j.DailyRollingFileAppender 
log4j.appender.info.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.info.File=d:/info.log
log4j.appender.info.Append=true
log4j.appender.info.Threshold=INFO
log4j.appender.info.layout=org.apache.log4j.PatternLayout 
log4j.appender.info.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
### File Appender
#######################
#log4j.appender.FILE=org.apache.log4j.FileAppender
#log4j.appender.FILE.File=E:/logs/all.log
#log4j.appender.FILE.Append=true
#log4j.appender.FILE.layout=org.apache.log4j.PatternLayout
#log4j.appender.CONSOLE.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
##log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n\u00A0
#####################
## Socket Appender
#####################
#log4j.appender.SOCKET=org.apache.log4j.RollingFileAppender
#log4j.appender.SOCKET.RemoteHost=localhost
#log4j.appender.SOCKET.Port=5001
#log4j.appender.SOCKET.LocationInfo=true
## Set up for Log Facter 5
#log4j.appender.SOCKET.layout=org.apache.log4j.PatternLayout
#log4j.appender.SOCET.layout.ConversionPattern=[start]%d{DATE}[DATE]%n%p[PRIORITY]%n%x[NDC]%n%t[THREAD]%n%c[CATEGORY]%n%m[MESSAGE]%n%n
#########################
## Log Factor 5 Appender
#########################
#log4j.appender.LF5_APPENDER=org.apache.log4j.lf5.LF5Appender
#log4j.appender.LF5_APPENDER.MaxNumberOfRecords=2000
########################
## SMTP Appender
########################
#log4j.appender.MAIL=org.apache.log4j.net.SMTPAppender
#log4j.appender.MAIL.Threshold=FATAL
#log4j.appender.MAIL.BufferSize=10
#[email protected]
#log4j.appender.MAIL.SMTPHost=mail.openwolf.com
#log4j.appender.MAIL.Subject=Log4J Message
#[email protected]
#log4j.appender.MAIL.layout=org.apache.log4j.PatternLayout
#log4j.appender.MAIL.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n
#########################
## JDBC Appender
########################
#log4j.appender.DATABASE=org.apache.log4j.jdbc.JDBCAppender
#log4j.appender.DATABASE.URL=jdbc:mysql://localhost:3306/test
#log4j.appender.DATABASE.driver=com.mysql.jdbc.Driver
#log4j.appender.DATABASE.user=root
#log4j.appender.DATABASE.password=root
#log4j.appender.DATABASE.sql=INSERT INTO LOG4J (Message) VALUES ('[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n')
#log4j.appender.DATABASE.layout=org.apache.log4j.PatternLayout
#log4j.appender.DATABASE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n
#log4j.appender.A1=org.apache.log4j.DailyRollingFileAppender
#log4j.appender.A1.File=SampleMessages.log4j
#log4j.appender.A1.DatePattern=yyyyMMdd-HH'.log4j'
#log4j.appender.A1.layout=org.apache.log4j.xml.XMLLayout
####################
### myself Appender
####################
#log4j.appender.im = net.cybercorlin.util.logger.appender.IMAppender
#log4j.appender.im.host = mail.cybercorlin.net
#log4j.appender.im.username = username
#log4j.appender.im.password = password
#log4j.appender.im.recipient = [email protected]
#log4j.appender.im.layout=org.apache.log4j.PatternLayout
#log4j.appender.im.layout.ConversionPattern =[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n

2.3 测试代码

package com.mybaits.demo;

import com.mybaits.demo.bean.User;
import com.mybaits.demo.service.UserService;
import com.mybaits.demo.service.UserService2;
import com.mybaits.demo.service.impl.UserServiceImpl;
import com.mybaits.demo.service.impl.UserServiceImpl2;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.apache.log4j.Logger;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;


/**
 * @ClassName: App2
 * @Description: TODO
 * @Author: liujianfu
 * @Date: 2021/01/30 21:54:06 
 * @Version: V1.0
 **/
public class App2 {
    private static Logger log = Logger.getLogger(App2.class);
    public static void main(String[] args) throws IOException {
        //方式一：传统方法
        //UserService userService=new UserServiceImpl();
        //userService.findAll();
        //方法二： 代理方式

        UserService2 userService=new UserServiceImpl2();
        userService.findAll();
        log.info("执行完了！！！");
    }

}