11、Logback日志框架介绍和SpringBoot整合实战 2节课

1、新日志框架LogBack介绍
     简介：日志介绍和新日志框架Logback讲解

1.常用处理java的日志组件 slf4j,log4j,logback,common-logging 等
    
     2、logback介绍：基于Log4j基础上大量改良，不能单独使用，推荐配合日志框架SLF4J来使用
         logback当前分成三个模块：logback-core,logback-classic和logback-access;
         logback-core是其它两个模块的基础模块

3、Logback的核心对象：
         Logger：日志记录器
         Appender：指定日志输出的目的地，目的地可以是控制台，文件
         Layout：日志布局 格式化日志信息的输出

4、日志级别：DEBUG < INFO < WARN < ERROR

===========log4j示例===========       
          ### 设置###
         log4j.rootLogger = debug,stdout,D,E

### 输出信息到控制抬 ###
         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

### 输出DEBUG 级别以上的日志到=D://logs/error.log ###
         log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
         log4j.appender.D.File = D://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

### 输出ERROR 级别以上的日志到=D://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

===========logback============
    
     4、Log4j日志转换为logback在线工具（支持log4j.properties转换为logback.xml,不支持 log4j.xml转换为logback.xml）
      https://logback.qos.ch/translator/

2、SpringBoot2.x日志讲解和自定义Logback配置实战
     简介：讲解SpringBoot2.x整合Logback配置实战

1、官网介绍：https://docs.spring.io/spring-boot/docs/2.1.0.BUILD-SNAPSHOT/reference/htmlsingle/#boot-features-logging

　　日志节选：

　　26.1 Log Format

The default log output from Spring Boot resembles the following example:

2014-03-05 10:57:51.112  INFO 45469 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/7.0.52
2014-03-05 10:57:51.253  INFO 45469 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2014-03-05 10:57:51.253  INFO 45469 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1358 ms
2014-03-05 10:57:51.698  INFO 45469 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2014-03-05 10:57:51.702  INFO 45469 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]

The following items are output:

• Date and Time: Millisecond precision and easily sortable.
• Log Level: ERROR, WARN, INFO, DEBUG, or TRACE.
• Process ID.
• A --- separator to distinguish the start of actual log messages.
• Thread name: Enclosed in square brackets (may be truncated for console output).
• Logger name: This is usually the source class name (often abbreviated).
• The log message.

各个组件案例：https://logback.qos.ch/manual/index.html
        
         2、分析SpringBoot启动日志
             1）默认情况下，Spring Boot将日志输出到控制台

3、整合Logback实战
             1）创建 日志文件logback-spring.xml，官方推荐 -spring.xml结尾
                 默认加载加载配置顺序 logback-spring.xml, logback-spring.groovy, logback.xml, or logback.groovy
            
             注释：
                 <configuration> 子节点
                 <appender></appender>                      
                 <logger></logger>
                 <root></root>(要加在最后)

　　配置文件代码：

 <?xml version="1.0" encoding="UTF-8" ?>
 <configuration>

     <appender name="consoleApp" class="ch.qos.logback.core.ConsoleAppender">
         <layout class="ch.qos.logback.classic.PatternLayout">
             <pattern>
                 %date{yyyy-MM-dd HH:mm:ss.SSS} %-5level[%thread]%logger{56}.%method:%L -%msg%n
             </pattern>
         </layout>
     </appender>

     <appender name="fileInfoApp" class="ch.qos.logback.core.rolling.RollingFileAppender">
         <filter class="ch.qos.logback.classic.filter.LevelFilter">
             <level>ERROR</level>
             <onMatch>DENY</onMatch>
             <onMismatch>ACCEPT</onMismatch>
         </filter>
         <encoder>
             <pattern>
                 %date{yyyy-MM-dd HH:mm:ss.SSS} %-5level[%thread]%logger{56}.%method:%L -%msg%n
             </pattern>
         </encoder>
         <!-- 滚动策略 -->
         <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
             <!-- 路径 -->
             <fileNamePattern>app_log/log/app.info.%d.log</fileNamePattern>
         </rollingPolicy>
     </appender>

     <appender name="fileErrorApp"
         class="ch.qos.logback.core.rolling.RollingFileAppender">
         <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
             <level>ERROR</level>
         </filter>
         <encoder>
             <pattern>
                 %date{yyyy-MM-dd HH:mm:ss.SSS} %-5level[%thread]%logger{56}.%method:%L -%msg%n
             </pattern>
         </encoder>

         <!-- 设置滚动策略 -->
         <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
             <!-- 路径 -->
             <fileNamePattern>app_log/log/app.err.%d.log</fileNamePattern>

             <!-- 控制保留的归档文件的最大数量，超出数量就删除旧文件，假设设置每个月滚动， 且<maxHistory> 是1，则只保存最近1个月的文件，删除之前的旧文件 -->
             <MaxHistory>1</MaxHistory>

         </rollingPolicy>
     </appender>

     <!-- 控制总的输出级别 -->
     <root level="INFO">
         <appender-ref ref="consoleApp" />
         <appender-ref ref="fileInfoApp" />
         <appender-ref ref="fileErrorApp" />
     </root>
 </configuration>

设置完成后会自动创建文件夹