SpringBoot - 第十章 | 日誌管理

Spring Boot使用Commons Logging進行所有內部日誌記錄，但保留底層日誌實現。為Java Util Logging，Log4J2和Logback提供了預設配置。在每種情況下，記錄器都預先配置為使用控制台輸出，並且還提供可選的文件輸出。

預設情況下，如果使用”Starters”，則將使用Logback進行日誌記錄。還包括適當的Logback路由，以確保使用Java Util Logging，Commons Logging，Log4J或SLF4J的依賴庫都能正常工作。

預設日誌

預設情況下，Spring Boot會用Logback來記錄日誌，並用INFO級別輸出到控制台。在運行應用程序和其他例子時，你應該已經看到很多INFO級別的日誌了。

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.3.RELEASE)

2019-03-19 09:38:22.003  INFO 2588 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Starting Chapter10Application on localhost with PID 2588 (/Users/morose/Documents/workspace-SpringBoot/chapter-10/target/classes started by morose in /Users/morose/Documents/workspace-SpringBoot/chapter-10)
2019-03-19 09:38:22.008  INFO 2588 --- [           main] c.j.l.s.chapter10.Chapter10Application   : No active profile set, falling back to default profiles: default
2019-03-19 09:38:23.144  INFO 2588 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-03-19 09:38:23.175  INFO 2588 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-03-19 09:38:23.175  INFO 2588 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.16]
2019-03-19 09:38:23.187  INFO 2588 --- [           main] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/morose/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2019-03-19 09:38:23.295  INFO 2588 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-03-19 09:38:23.295  INFO 2588 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1212 ms
2019-03-19 09:38:23.554  INFO 2588 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-03-19 09:38:23.803  INFO 2588 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-03-19 09:38:23.806  INFO 2588 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Started Chapter10Application in 2.149 seconds (JVM running for 2.555)

格式化日誌

針對其輸出內容元素做說明

訊息內容	元素	說明
2019-03-19 09:38:23.144	時間日期	精確到毫秒
INFO	日誌級別	ERROR, WARN, INFO, DEBUG or TRACE
2588	進程ID	進程ID
- - -	分隔符	- - - 標識實際日誌的開始
[ main]	線程名	方括號括起來（可能會截斷控制台輸出）
o.s.b.w.embedded.tomcat.TomcatWebServer	Logger名	通常使用源代碼的類名
Tomcat initialized with port(s): 8080 (http)	日誌內容	日誌內容

控制台輸出

在Spring Boot中預設配置了FATAL、ERROR、WARN和INFO級別的日誌輸出到控制台。

撰寫 LoggerDemoController

瀏覽 http://localhost:8080/log?message=123

可以看到輸出的Log等級，就是包含INFO以上的等級

我們可以通過兩種方式切換至DEBUG級別：

在運行命令後加入 –debug，如：$java -jar xxx.jar –debug
在application.properties中 配置debug=true，該屬性置為true的時候，核心Logger（包含嵌入式容器、hibernate、spring）會輸出更多內容，但是你自己應用的日誌並不會輸出為DEBUG級別。
修改 application.properties

1	debug=true

啟動應用，並瀏覽http://localhost:8080/log?message=123

2019-03-19 10:35:42.209 DEBUG 2722 --- [           main] .c.l.ClasspathLoggingApplicationListener : Application started with classpath: [file:/Users/morose/Documents/workspace-SpringBoot/chapter-10/target/classes/, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot-starter-web/2.1.3.RELEASE/spring-boot-starter-web-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot-starter/2.1.3.RELEASE/spring-boot-starter-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot/2.1.3.RELEASE/spring-boot-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/2.1.3.RELEASE/spring-boot-autoconfigure-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot-starter-logging/2.1.3.RELEASE/spring-boot-starter-logging-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar, file:/Users/morose/.m2/repository/ch/qos/logback/logback-core/1.2.3/logback-core-1.2.3.jar, file:/Users/morose/.m2/repository/org/apache/logging/log4j/log4j-to-slf4j/2.11.2/log4j-to-slf4j-2.11.2.jar, file:/Users/morose/.m2/repository/org/apache/logging/log4j/log4j-api/2.11.2/log4j-api-2.11.2.jar, file:/Users/morose/.m2/repository/org/slf4j/jul-to-slf4j/1.7.25/jul-to-slf4j-1.7.25.jar, file:/Users/morose/.m2/repository/org/yaml/snakeyaml/1.23/snakeyaml-1.23.jar, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot-starter-json/2.1.3.RELEASE/spring-boot-starter-json-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.9.8/jackson-databind-2.9.8.jar, file:/Users/morose/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.9.0/jackson-annotations-2.9.0.jar, file:/Users/morose/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.9.8/jackson-core-2.9.8.jar, file:/Users/morose/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.9.8/jackson-datatype-jdk8-2.9.8.jar, file:/Users/morose/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.9.8/jackson-datatype-jsr310-2.9.8.jar, file:/Users/morose/.m2/repository/com/fasterxml/jackson/module/jackson-module-parameter-names/2.9.8/jackson-module-parameter-names-2.9.8.jar, file:/Users/morose/.m2/repository/org/hibernate/validator/hibernate-validator/6.0.14.Final/hibernate-validator-6.0.14.Final.jar, file:/Users/morose/.m2/repository/javax/validation/validation-api/2.0.1.Final/validation-api-2.0.1.Final.jar, file:/Users/morose/.m2/repository/org/jboss/logging/jboss-logging/3.3.2.Final/jboss-logging-3.3.2.Final.jar, file:/Users/morose/.m2/repository/com/fasterxml/classmate/1.4.0/classmate-1.4.0.jar, file:/Users/morose/.m2/repository/org/springframework/spring-web/5.1.5.RELEASE/spring-web-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/spring-beans/5.1.5.RELEASE/spring-beans-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/spring-webmvc/5.1.5.RELEASE/spring-webmvc-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/spring-aop/5.1.5.RELEASE/spring-aop-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/spring-context/5.1.5.RELEASE/spring-context-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/spring-expression/5.1.5.RELEASE/spring-expression-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/2.1.3.RELEASE/spring-boot-starter-tomcat-2.1.3.RELEASE.jar, file:/Users/morose/.m2/repository/javax/annotation/javax.annotation-api/1.3.2/javax.annotation-api-1.3.2.jar, file:/Users/morose/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/9.0.16/tomcat-embed-core-9.0.16.jar, file:/Users/morose/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/9.0.16/tomcat-embed-el-9.0.16.jar, file:/Users/morose/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/9.0.16/tomcat-embed-websocket-9.0.16.jar, file:/Users/morose/.m2/repository/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar, file:/Users/morose/.m2/repository/org/springframework/spring-core/5.1.5.RELEASE/spring-core-5.1.5.RELEASE.jar, file:/Users/morose/.m2/repository/org/springframework/spring-jcl/5.1.5.RELEASE/spring-jcl-5.1.5.RELEASE.jar]

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.3.RELEASE)

2019-03-19 10:35:42.319  INFO 2722 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Starting Chapter10Application on localhost with PID 2722 (/Users/morose/Documents/workspace-SpringBoot/chapter-10/target/classes started by morose in /Users/morose/Documents/workspace-SpringBoot/chapter-10)
2019-03-19 10:35:42.320  INFO 2722 --- [           main] c.j.l.s.chapter10.Chapter10Application   : No active profile set, falling back to default profiles: default
2019-03-19 10:35:42.320 DEBUG 2722 --- [           main] o.s.boot.SpringApplication               : Loading source class com.jj.learning.springboot.chapter10.Chapter10Application
2019-03-19 10:35:42.389 DEBUG 2722 --- [           main] o.s.b.c.c.ConfigFileApplicationListener  : Loaded config file 'file:/Users/morose/Documents/workspace-SpringBoot/chapter-10/target/classes/application.properties' (classpath:/application.properties)
2019-03-19 10:35:42.390 DEBUG 2722 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@50a7bc6e
2019-03-19 10:35:43.400 DEBUG 2722 --- [           main] .s.b.w.e.t.TomcatServletWebServerFactory : Code archive: /Users/morose/.m2/repository/org/springframework/boot/spring-boot/2.1.3.RELEASE/spring-boot-2.1.3.RELEASE.jar
2019-03-19 10:35:43.401 DEBUG 2722 --- [           main] .s.b.w.e.t.TomcatServletWebServerFactory : Code archive: /Users/morose/.m2/repository/org/springframework/boot/spring-boot/2.1.3.RELEASE/spring-boot-2.1.3.RELEASE.jar
2019-03-19 10:35:43.401 DEBUG 2722 --- [           main] .s.b.w.e.t.TomcatServletWebServerFactory : Document root: /Users/morose/Documents/workspace-SpringBoot/chapter-10/src/main/webapp
2019-03-19 10:35:43.434  INFO 2722 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-03-19 10:35:43.467  INFO 2722 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-03-19 10:35:43.468  INFO 2722 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.16]
2019-03-19 10:35:43.483  INFO 2722 --- [           main] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/morose/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2019-03-19 10:35:43.602  INFO 2722 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-03-19 10:35:43.602  INFO 2722 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1212 ms
2019-03-19 10:35:43.635 DEBUG 2722 --- [           main] o.s.b.w.s.ServletContextInitializerBeans : Mapping filters: characterEncodingFilter urls=[/*], hiddenHttpMethodFilter urls=[/*], formContentFilter urls=[/*], requestContextFilter urls=[/*]
2019-03-19 10:35:43.636 DEBUG 2722 --- [           main] o.s.b.w.s.ServletContextInitializerBeans : Mapping servlets: dispatcherServlet urls=[/]
2019-03-19 10:35:43.664 DEBUG 2722 --- [           main] o.s.b.w.s.f.OrderedRequestContextFilter  : Filter 'requestContextFilter' configured for use
2019-03-19 10:35:43.665 DEBUG 2722 --- [           main] .s.b.w.s.f.OrderedHiddenHttpMethodFilter : Filter 'hiddenHttpMethodFilter' configured for use
2019-03-19 10:35:43.665 DEBUG 2722 --- [           main] s.b.w.s.f.OrderedCharacterEncodingFilter : Filter 'characterEncodingFilter' configured for use
2019-03-19 10:35:43.665 DEBUG 2722 --- [           main] o.s.b.w.s.f.OrderedFormContentFilter     : Filter 'formContentFilter' configured for use
2019-03-19 10:35:43.890  INFO 2722 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-03-19 10:35:44.111 DEBUG 2722 --- [           main] ConditionEvaluationReportLoggingListener : 


============================
CONDITIONS EVALUATION REPORT
============================


Positive matches:
-----------------

   CodecsAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.codec.CodecConfigurer' (OnClassCondition)

   CodecsAutoConfiguration.JacksonCodecConfiguration matched:
      - @ConditionalOnClass found required class 'com.fasterxml.jackson.databind.ObjectMapper' (OnClassCondition)

   
  省略...


Negative matches:
-----------------

   ActiveMQAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'javax.jms.ConnectionFactory' (OnClassCondition)

   AopAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.aspectj.lang.annotation.Aspect' (OnClassCondition)

   省略...


Exclusions:
-----------

    None


Unconditional classes:
----------------------

    org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration

    org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration

    org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration



2019-03-19 10:35:44.160  INFO 2722 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-03-19 10:35:44.164  INFO 2722 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Started Chapter10Application in 2.179 seconds (JVM running for 2.558)
2019-03-19 10:36:02.294  INFO 2722 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-03-19 10:36:02.294  INFO 2722 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2019-03-19 10:36:02.300  INFO 2722 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 6 ms
2019-03-19 10:36:02.340  INFO 2722 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : info(訊息):123
2019-03-19 10:36:02.342  WARN 2722 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : warn(警告):123
2019-03-19 10:36:02.342 ERROR 2722 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : error(錯誤):123
2019-03-19 10:36:02.342 ERROR 2722 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : fatal(致命):123

可以看到多輸出了很多的資訊，但是在最後自己的應用Log依舊是INFO等級的，這就是「核心Logger（包含嵌入式容器、hibernate、spring）會輸出更多內容，但是你自己應用的日誌並不會輸出為DEBUG級別。」這句話的意思。

文件輸出

Spring Boot預設配置只會輸出到控制台，並不會記錄到文件中，但是我們通常生產環境使用時都需要以文件方式記錄。

若要增加文件輸出，需要在application.properties中配置logging.file或logging.path屬性。

logging.file，設置文件，可以是絕對路徑，也可以是相對路徑。如：logging.file=my.log
logging.path，設置目錄，會在該目錄下建立spring.log文件，並寫入日誌內容，如：logging.path=/var/log

註：二者不能同時使用，若同時使用，則只有logging.file生效，預設情況下，日誌文件的大小達到10MB時會截斷，產生新的日誌文件，預設級別為：ERROR、WARN、INFO

修改 application.properties

1	logging.file=my.log

啟動應用，並瀏覽http://localhost:8080/log?message=123

可以在根目錄發現產生了my.log的日誌檔案(chapter-10/my.log)，開啟檔案內容為。

2019-03-19 11:04:31.532  INFO 2807 --- [main] c.j.l.s.chapter10.Chapter10Application   : Starting Chapter10Application on localhost with PID 2807 (/Users/morose/Documents/workspace-SpringBoot/chapter-10/target/classes started by morose in /Users/morose/Documents/workspace-SpringBoot/chapter-10)
2019-03-19 11:04:31.536  INFO 2807 --- [main] c.j.l.s.chapter10.Chapter10Application   : No active profile set, falling back to default profiles: default
2019-03-19 11:04:32.588  INFO 2807 --- [main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-03-19 11:04:32.625  INFO 2807 --- [main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-03-19 11:04:32.626  INFO 2807 --- [main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.16]
2019-03-19 11:04:32.638  INFO 2807 --- [main] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/morose/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2019-03-19 11:04:32.751  INFO 2807 --- [main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-03-19 11:04:32.751  INFO 2807 --- [main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1150 ms
2019-03-19 11:04:33.027  INFO 2807 --- [main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-03-19 11:04:33.281  INFO 2807 --- [main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-03-19 11:04:33.284  INFO 2807 --- [main] c.j.l.s.chapter10.Chapter10Application   : Started Chapter10Application in 2.061 seconds (JVM running for 2.486)
2019-03-19 11:04:43.352  INFO 2807 --- [http-nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-03-19 11:04:43.353  INFO 2807 --- [http-nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2019-03-19 11:04:43.359  INFO 2807 --- [http-nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 6 ms
2019-03-19 11:04:43.392  INFO 2807 --- [http-nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : info(訊息):123
2019-03-19 11:04:43.394  WARN 2807 --- [http-nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : warn(警告):123
2019-03-19 11:04:43.395 ERROR 2807 --- [http-nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : error(錯誤):123
2019-03-19 11:04:43.395 ERROR 2807 --- [http-nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : fatal(致命):123

級別控制

在Spring Boot中只需要在application.properties中進行配置完成日誌記錄的級別控制。

配置格式：logging.level.*=LEVEL

logging.level：日誌級別控制前綴，*為包名或Logger名
LEVEL：選項TRACE, DEBUG, INFO, WARN, ERROR, FATAL, OFF
舉例：

com.jj.learning.springboot.chapter10.controller
logging.level.com.jj=DEBUG：com.jj包下所有class以DEBUG級別輸出
logging.level.root=WARN：root日誌以WARN級別輸出

修改 application.properties

# root日誌以WARN級別輸出
logging.level.root=WARN
# com.jj包下所有class以DEBUG級別輸出
logging.level.com.jj=DEBUG

啟動應用後的日誌

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.3.RELEASE)

2019-03-19 10:54:01.433  INFO 2783 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Starting Chapter10Application on localhost with PID 2783 (/Users/morose/Documents/workspace-SpringBoot/chapter-10/target/classes started by morose in /Users/morose/Documents/workspace-SpringBoot/chapter-10)
2019-03-19 10:54:01.435 DEBUG 2783 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Running with Spring Boot v2.1.3.RELEASE, Spring v5.1.5.RELEASE
2019-03-19 10:54:01.436  INFO 2783 --- [           main] c.j.l.s.chapter10.Chapter10Application   : No active profile set, falling back to default profiles: default
2019-03-19 10:54:03.184  INFO 2783 --- [           main] c.j.l.s.chapter10.Chapter10Application   : Started Chapter10Application in 2.15 seconds (JVM running for 2.579)

瀏覽 http://localhost:8080/log?message=123

2019-03-19 10:56:54.537 DEBUG 2783 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : debug(調試):123
2019-03-19 10:56:54.539  INFO 2783 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : info(訊息):123
2019-03-19 10:56:54.539  WARN 2783 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : warn(警告):123
2019-03-19 10:56:54.539 ERROR 2783 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : error(錯誤):123
2019-03-19 10:56:54.539 ERROR 2783 --- [nio-8080-exec-1] c.j.l.s.c.c.LoggerDemoController         : fatal(致命):123

可以看到日誌輸出的等級為包含Debug以上的日誌

自定義日誌配置

由於日誌服務一般都在ApplicationContext建立前就初始化了，它並不是必須通過Spring的配置文件控制。因此通過系統屬性和傳統的Spring Boot外部配置文件依然可以很好的支持日誌控制和管理。

根據不同的日誌系統，你可以按如下規則組織配置文件名，就能被正確加載：

Logback：logback-spring.xml, logback-spring.groovy, logback.xml, logback.groovy
Log4j：log4j-spring.properties, log4j-spring.xml, log4j.properties, log4j.xml
Log4j2：log4j2-spring.xml, log4j2.xml
JDK (Java Util Logging)：logging.properties

Spring Boot官方推薦優先使用帶有-spring的文件名作為你的日誌配置（如使用logback-spring.xml，而不是logback.xml）

自定義輸出格式

在Spring Boot中可以通過在application.properties配置如下參數控制輸出格式：

logging.pattern.console：定義輸出到控制台的樣式（不支持JDK Logger）
logging.pattern.file：定義輸出到文件的樣式（不支持JDK Logger）

註：以上參考了
程序猿DD-翟永超的 Spring Boot日志管理文章。

SpringBoot - 第九章 | Swagger2的集成和使用

SpringBoot - 第十一章 | 多環境配置

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本文由J.J. Huang 創作，採用CC BY 3.0 TW協議進行許可。可自由轉載、引用，但需署名作者且註明文章出處。

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J.J. Huang 2019-03-20 Spring Boot 瀏覽次數：次 {{moment(1553044200000).fromNow()}}