SpringBoot2.x使用slf4j+logback日志，以及动态修改日志级别
前言：记录一下SpringBoot学习历程
SpringBoot中内置了slf4j日志框架，我们直接使用就好了。
使用slf4j
新建一个测试controller，如：
public final Logger log = LoggerFactory.getLogger(getClass());
@GetMapping("/test")
public void test() {
log.info("Logger Level ：{}", "info");
log.error("Logger Level ：{}", "error");
log.debug("Logger Level ：{}", "debug");
log.warn("Logger Level ：{}", "warn");
}
启动项目，访问test请求，log日志就可以打印了。
每次都写：==public final Logger log = LoggerFactory.getLogger(getClass());==是不是觉得很繁琐，有一种更方便的办法就是使用注解。
首先，修改pom文件，导入依赖：
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
dependency>
关于lombok还有很多别的功能，比如使用@Data注解可以为一个bean自动生成getter , setter方法及toString 方法
然后在测试controller中使用注解：@Slf4j
@Slf4j
@RestController()
public class HelloController {
@GetMapping("/test")
public void test() {
log.info("Logger Level ：{}", "info");
log.error("Logger Level ：{}", "error");
log.debug("Logger Level ：{}", "debug");
log.warn("Logger Level ：{}", "warn");
}
}
这样即使不用写public final Logger log = LoggerFactory.getLogger(getClass());，都可以打印日志了
使用slf4j + logback 记录日志
新建一个logback-spring.xml（或者logback.xml，官方推荐使用-spring,可以使用springProfile
实现多环境日志配置），logback-spring.xml示例：
<configuration scan="true" scanPeriod="10 seconds">
<contextName>logbackcontextName>
<property name="log.path" value="logs" />
<property name="service.name" value="demo" />
<conversionRule conversionWord="clr" converterClass="org.springframework.boot.logging.logback.ColorConverter" />
<conversionRule conversionWord="wex" converterClass="org.springframework.boot.logging.logback.WhitespaceThrowableProxyConverter" />
<conversionRule conversionWord="wEx" converterClass="org.springframework.boot.logging.logback.ExtendedWhitespaceThrowableProxyConverter" />
<property name="CONSOLE_LOG_PATTERN" value="${CONSOLE_LOG_PATTERN:-%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %clr(${LOG_LEVEL_PATTERN:-%5p}) %clr(${PID:- }){magenta} %clr(---){faint} %clr([%15.15t]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n${LOG_EXCEPTION_CONVERSION_WORD:-%wEx}}"/>
<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
<filter class="ch.qos.logback.classic.filter.ThresholdFilter">
<level>debuglevel>
filter>
<encoder>
<Pattern>${CONSOLE_LOG_PATTERN}Pattern>
<charset>UTF-8charset>
encoder>
appender>
<appender name="LOGFILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${log.path}/${service.name}.logfile>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%npattern>
<charset>UTF-8charset>
encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${log.path}/${service.name}-%d{yyyy-MM-dd}.%i.logfileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MBmaxFileSize>
timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15maxHistory>
rollingPolicy>
appender>
<appender name="DEBUG_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${log.path}/${service.name}-DEBUG.logfile>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%npattern>
<charset>UTF-8charset>
encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${log.path}/web-debug-%d{yyyy-MM-dd}.%i.logfileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MBmaxFileSize>
timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15maxHistory>
rollingPolicy>
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>debuglevel>
<onMatch>ACCEPTonMatch>
<onMismatch>DENYonMismatch>
filter>
appender>
<appender name="INFO_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${log.path}/${service.name}-INFO.logfile>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%npattern>
<charset>UTF-8charset>
encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${log.path}/${service.name}-INFO-%d{yyyy-MM-dd}.%i.logfileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MBmaxFileSize>
timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15maxHistory>
rollingPolicy>
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>infolevel>
<onMatch>ACCEPTonMatch>
<onMismatch>DENYonMismatch>
filter>
appender>
<appender name="WARN_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${log.path}/${service.name}-WARN.logfile>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%npattern>
<charset>UTF-8charset>
encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${log.path}/${service.name}-WARN-%d{yyyy-MM-dd}.%i.logfileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MBmaxFileSize>
timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15maxHistory>
rollingPolicy>
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>warnlevel>
<onMatch>ACCEPTonMatch>
<onMismatch>DENYonMismatch>
filter>
appender>
<appender name="ERROR_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${log.path}/${service.name}-ERROR.logfile>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%npattern>
<charset>UTF-8charset>
encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${log.path}/${service.name}-ERROR-%d{yyyy-MM-dd}.%i.logfileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MBmaxFileSize>
timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15maxHistory>
rollingPolicy>
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>ERRORlevel>
<onMatch>ACCEPTonMatch>
<onMismatch>DENYonMismatch>
filter>
appender>
<springProfile name="dev">
<root level="info">
<appender-ref ref="CONSOLE" />
root>
springProfile>
<springProfile name="test">
<root level="info">
<appender-ref ref="LOGFILE" />
<appender-ref ref="DEBUG_FILE" />
<appender-ref ref="INFO_FILE" />
<appender-ref ref="ERROR_FILE" />
<appender-ref ref="WARN_FILE" />
root>
springProfile>
<springProfile name="prod">
<root level="info">
<appender-ref ref="LOGFILE" />
<appender-ref ref="INFO_FILE" />
<appender-ref ref="ERROR_FILE" />
<appender-ref ref="WARN_FILE" />
root>
springProfile>
configuration>
dev开发环境则只打印到控制台上（注意：springProfile name=“prod” name,需要配置不同的环境ID，配置不同环境可参考我之前博客:https://blog.csdn.net/qq_36174487/article/details/89419347），
我们以测试环境启动项目，生成日志为logs文件目录下：
这样日志就成功被记录到.log文件中了，并且按照日期来归档，可设置文件大小，过期天数等，附上博主归档日志：
动态修改日志级别
首先更改yml文件：
# 1.5.x 版本中是 management.security.enabled=false
management:
endpoints:
web:
exposure:
include: "loggers"
不然访问loggers端点时，会报如下错误：
{
"timestamp": 1556596470000,
"status": 401,
"error": "Unauthorized",
"message": "Full authentication is required to access this resource.",
"path": "/loggers/com.didispace"
}
启动项目，访问地址：http://127.0.0.1:8081/actuator/loggers
结果：
{
"levels": [
"OFF",
"ERROR",
"WARN",
"INFO",
"DEBUG",
"TRACE"
],
"loggers": {
"ROOT": {
"configuredLevel": "INFO",
"effectiveLevel": "INFO"
},
"com": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example.demo": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example.demo.DemoApplication": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example.demo.task": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example.demo.task.Scheduling": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example.demo.web": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"com.example.demo.web.HelloController": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"io": {
"configuredLevel": null,
"effectiveLevel": "INFO"
},
"io.micrometer": {
"configuredLevel": null,
"effectiveLevel": "INFO"
}
//详细包日志级别省略
}
}
其中com.com.example,com.example.demo 对应项目的包名，可针对性的更改不同包的日志级别，
比如更改 com.example.demo 级别为DEBUG
发起请求：http://127.0.0.1:8081/actuator/loggers/com.example.demo
参数：
{
"configuredLevel":"DEBUG"
}
参数格式一定不能乱！
再次访问test请求：dubug级别日志就可被打印出来了
还可以使用根据Actuator提供的RESTful API定制界面，或使用 Spring Boot Admin ，可视化修改日志级别
或者自定义请求，logger.setLevel(LEVELS.convertSystemToNative(level)); 等来更改，有兴趣的同学可以试试！
参考资料：
1.https://blog.csdn.net/dyc87112/article/details/54866244/
2.https://blog.csdn.net/heguiliang_123/article/details/80296745
3.https://my.oschina.net/eacdy/blog/3040211