Logback

1、官方文档

https://logback.qos.ch/manual/index.html

2、下载地址

https://logback.qos.ch/download.html

3、快速使用

这里主要是 logback + SLF4j 配合使用。

1. pom引入jar包

<!-- 日志：slf4j + logback  -->
	<dependency>
	    <groupId>org.slf4j</groupId>
	    <artifactId>slf4j-api</artifactId>
	    <version>1.7.31</version>
	</dependency>
	<dependency>
	    <groupId>ch.qos.logback</groupId>
	    <artifactId>logback-core</artifactId>
	    <version>1.2.3</version>
	</dependency>
	<dependency>
	    <groupId>ch.qos.logback</groupId>
	    <artifactId>logback-classic</artifactId>
	    <version>1.2.3</version>
	    <scope>compile</scope>
	</dependency>

2. src/main/resource 创建 logback.xml 文件

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" >
    <contextName>logback</contextName>
    <property name="log.path" value="./logs" />
  <property name="CONSOLE_LOG_PATTERN" 
         value="%d{yyyy-MM-dd HH:mm:ss.SSS} ${LOG_LEVEL_PATTERN:-%5p} ${PID:- } --- [%15.15t] %-40.40logger{39} :  %m%n}"/> 
    <!--1. 输出到控制台-->
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <!--此日志appender是为开发使用，只配置最底级别，控制台输出的日志级别是大于或等于此级别的日志信息-->
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <level>INFO</level>
        </filter>
        <encoder>
            <pattern>${CONSOLE_LOG_PATTERN}</pattern>
            <!-- 设置字符集 -->
            <charset>UTF-8</charset>
        </encoder>
    </appender>
    <!--root 标签和其他logger标签起相同的作用，只是其他logger 可以继承此标签的属性--> 
    <root>
        <appender-ref ref="CONSOLE" />
    </root>
</configuration>

5. Java 代码

package com.black.nginx.app;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class NginxApp {

    private static Logger logger = LoggerFactory.getLogger(NginxApp.class);
	
	public static void main(String[] args) {
		logger.info("app start ...");
		
		
		logger.info("app shutdown .");
	}
}

4. 效果

2021-07-13 23:19:41.591  INFO   --- [           main] com.black.nginx.app.NginxApp             :  app start ...
2021-07-13 23:19:41.596  INFO   --- [           main] com.black.nginx.app.NginxApp             :  app shutdown .

4、logback.xml拷贝就用

• console 打印

<?xml version="1.0" encoding="UTF-8"?>
<!-- 日志级别从低到高分为TRACE < DEBUG < INFO < WARN < ERROR < FATAL，如果设置为WARN，则低于WARN的信息都不会输出 -->
<!-- scan:当此属性设置为true时，配置文档如果发生改变，将会被重新加载，默认值为true -->
<!-- scanPeriod:设置监测配置文档是否有修改的时间间隔，如果没有给出时间单位，默认单位是毫秒。
                 当scan为true时，此属性生效。默认的时间间隔为1分钟。 -->
<!-- debug:当此属性设置为true时，将打印出logback内部日志信息，实时查看logback运行状态。默认值为false。 -->

<configuration scan="true" >
    <contextName>logback</contextName>
    <!--0. 日志格式 -->
    <property name="CONSOLE_LOG_PATTERN" 
         value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%-5p] [%-10.15t] %20.30logger{30}.%M[line:%L]: %m%n}"/> 
    <!--1. 输出到控制台-->
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>${CONSOLE_LOG_PATTERN}</pattern>
            <!-- 设置字符集 -->
            <charset>UTF-8</charset>
        </encoder>
    </appender>
    <root>
        <appender-ref ref="CONSOLE" />
    </root>
</configuration>

打印结果：

2021-07-14 23:00:38.497 [INFO ] [main      ] com.black.nginx.app.NginxApp.main[line:11]: app start ...
2021-07-14 23:00:38.497 [INFO ] [main      ] com.black.nginx.app.NginxApp.main[line:14]: app shutdown .

• 日志文件
  1、固定文件

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" >
    <!--0. 日志格式 -->
    <property name="CONSOLE_LOG_PATTERN" 
         value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%-5p] [%-10.15t] %20.30logger{30}.%M[line:%L]: %m%n}"/> 
    <!-- 时间戳 -->
    <timestamp key="file_name_date" datePattern="yyyyMMdd"/>
    <!--1. 记录日志到文件-->
    <appender name="LogFile" class="ch.qos.logback.core.FileAppender">
        <!-- 日志文件名 -->
        <file>${file_name_date}/log-info-${file_name_date}.log</file>
        <encoder>
            <pattern>${CONSOLE_LOG_PATTERN}</pattern>
            <!-- 设置字符集 -->
            <charset>UTF-8</charset>
        </encoder>
    </appender>
    <root>
        <appender-ref ref="LogFile" />
    </root>
</configuration>

2、基于时间分隔文件

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" >
    <!--0. 日志格式 -->
    <property name="CONSOLE_LOG_PATTERN" 
         value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%-5p] [%-10.15t] %20.30logger{30}.%M[line:%L]: %m%n}"/> 
    <!-- 时间戳 -->
    <timestamp key="file_name_date" datePattern="yyyyMMdd"/>
    <!--1. 记录日志到文件-->
     <appender name="ROLL_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        
        <!--   prudent 支持多个JVM 写入统一日志文件 -->
        <prudent>true</prudent>
        
        <!-- 设置滚动策略 -->
        <!-- FixedWindowRollingPolicy: -->
        <!-- TimeBasedRollingPolicy: -->
        <!-- SizeAndTimeBasedRollingPolicy: -->
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- 文件名以及文件路径（如果日志文件名以.gz or .zip，则半夜会自动压缩日志） -->
            <fileNamePattern>logFile.%d{yyyy-MM-dd}.log</fileNamePattern>
            <!-- 日志保留天数（如果 fileNamePattern 是按天滚动的）  ，超过30天的日志会异步删除-->
		    <maxHistory>30</maxHistory>
		    <!-- 日志文件总大小，超过3GB时，会删除旧的日志文件 --> 
		    <totalSizeCap>3GB</totalSizeCap>
        </rollingPolicy>
    </appender>
    <root>
        <appender-ref ref="ROLL_FILE" />
    </root>
</configuration>

3、基于时间和大小分隔文件

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" >
    <!--0. 日志格式 -->
    <property name="CONSOLE_LOG_PATTERN" 
         value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%-5p] [%-10.15t] %20.30logger{30}.%M[line:%L]: %m%n}"/> 
    <!-- 时间戳 -->
    <timestamp key="file_name_date" datePattern="yyyyMMdd"/>
    <!--1. 记录日志到文件-->
     <appender name="ROLL_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        
        <!--   prudent 支持多个JVM 写入统一日志文件 -->
        <prudent>true</prudent>
        
        <!-- 设置滚动策略 -->
        <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
            <!-- 文件名以及文件路径（如果日志文件名以.gz or .zip，则半夜会自动压缩日志） -->
            <fileNamePattern>logFile.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
            <!-- 每个日志文件最多100M -->
            <maxFileSize>100MB</maxFileSize> 
            <!-- 日志保留天数（如果 fileNamePattern 是按天滚动的）  ，超过30天的日志会异步删除-->
            <maxHistory>30</maxHistory>
            <!-- 日志文件总大小，超过20GB时，会删除旧的日志文件 --> 
            <totalSizeCap>20GB</totalSizeCap>
        </rollingPolicy>
    </appender>
    <root>
        <appender-ref ref="ROLL_FILE" />
    </root>
</configuration>

4、基于固定大小

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" >
    <!--0. 日志格式 -->
    <property name="CONSOLE_LOG_PATTERN" 
         value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%-5p] [%-10.15t] %20.30logger{30}.%M[line:%L]: %m%n}"/> 
    <!-- 时间戳 -->
    <timestamp key="file_name_date" datePattern="yyyyMMdd"/>
    <!--1. 记录日志到文件-->
     <appender name="ROLL_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        
        <file>log-info.log</file>

        <!-- 设置滚动策略 -->
        <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
	      <fileNamePattern>log-info.%i.log.zip</fileNamePattern>
	      <minIndex>1</minIndex>
	      <maxIndex>3</maxIndex>
	    </rollingPolicy>
	    
	    <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
	      <maxFileSize>5MB</maxFileSize>
	    </triggeringPolicy>
	    <encoder>
	      <pattern>${CONSOLE_LOG_PATTERN}</pattern>
	    </encoder>
    </appender>
    <root level="INFO">
        <appender-ref ref="ROLL_FILE" />
    </root>
</configuration>

5、logback.xml Appender 详解

• ConsoleAppender

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <!-- encoders are assigned the type
         ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n</pattern>
    </encoder>
  </appender>
  <root level="DEBUG">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

• FileAppender

<configuration>
  <!-- Insert the current time formatted as "yyyyMMdd"T"HHmmss" under
       the key "bySecond" into the logger context. This value will be
       available to all subsequent configuration elements. -->
  <timestamp key="bySecond" datePattern="yyyyMMdd"T"HHmmss"/>

  <appender name="FILE" class="ch.qos.logback.core.FileAppender">
    <!-- use the previously created timestamp to create a uniquely
         named log file -->
    <file>log-${bySecond}.txt</file>
    <encoder>
      <pattern>%logger{35} - %msg%n</pattern>
    </encoder>
  </appender>
  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

• RollingFileAppender

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>logFile.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <!-- daily rollover -->
      <fileNamePattern>logFile.%d{yyyy-MM-dd}.log</fileNamePattern>

      <!-- keep 30 days" worth of history capped at 3GB total size -->
      <maxHistory>30</maxHistory>
      <totalSizeCap>3GB</totalSizeCap>

    </rollingPolicy>

    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender> 

  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <!-- Support multiple-JVM writing to the same log file -->
    <prudent>true</prudent>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <fileNamePattern>logFile.%d{yyyy-MM-dd}.log</fileNamePattern>
      <maxHistory>30</maxHistory> 
      <totalSizeCap>3GB</totalSizeCap>
    </rollingPolicy>

    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender> 

  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

<configuration>
  <appender name="ROLLING" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>mylog.txt</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
      <!-- rollover daily -->
      <fileNamePattern>mylog-%d{yyyy-MM-dd}.%i.txt</fileNamePattern>
       <!-- each file should be at most 100MB, keep 60 days worth of history, but at most 20GB -->
       <maxFileSize>100MB</maxFileSize>
       <maxHistory>60</maxHistory>
       <totalSizeCap>20GB</totalSizeCap>
    </rollingPolicy>
    <encoder>
      <pattern>%msg%n</pattern>
    </encoder>
  </appender>


  <root level="DEBUG">
    <appender-ref ref="ROLLING" />
  </root>

</configuration>

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>test.log</file>

    <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
      <fileNamePattern>tests.%i.log.zip</fileNamePattern>
      <minIndex>1</minIndex>
      <maxIndex>3</maxIndex>
    </rollingPolicy>

    <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
      <maxFileSize>5MB</maxFileSize>
    </triggeringPolicy>
    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender>
  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>test.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
      <fileNamePattern>test.%i.log.zip</fileNamePattern>
      <minIndex>1</minIndex>
      <maxIndex>3</maxIndex>
    </rollingPolicy>

    <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
      <maxFileSize>5MB</maxFileSize>
    </triggeringPolicy>
    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender>
        
  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

fileNamePattern 与 Rollover关系：

Rollover 就是 maxHistory 属性的单位。

6、logback.xml PatternLayout 详解

抄自https://logback.qos.ch/manual/layouts.html

我对 logback.xml 中 pattern 里的 %d %c 什么的搞不明白什么含义，下面就介绍一下，pattern 中使用到的Conversion Word的含义：

• %c{length}

或 %lo{length} %logger{length}

• %C{length}

或 %class{length}

打印类名

• %cn

或 contextName

• %d{pattern}

或 %date{pattern} %d{pattern, timezone}
%date{pattern, timezone}

打印日期

• %F / %file

java 源文件的名字

• %M / %method
  打印日志所在方法名

• %L / %line
  logger.info等代码所在文件的行数

• %m / %msg / %message
  打印 用户日志信息,即 logger.info()的参数

• %n
  换行

• %p / %le / %level
  日志事件等级 INFO ，DEBUG等

• %r / %relative
  应用启动执行，一直到打印日志，执行的毫秒数

• %t / %thread
  线程名

• %ex{depth}

exception{depth}
throwable{depth}

打印异常信息控制

• %property{key}
  打印Properties文件中的key 对应的 value

• %caller{depth}
  打印方法调用层级信息

7、logback.xml Format modifiers 详解