现在的很多应用默认情况下就带了很多的日志输出, 比如下面的 java spring-boot 框架启动时的日志:
{spring.web.resources.chain.cache=false, spring.web.resources.cache.period=0}
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.4.0)
2020-11-28 10:54:18.418 INFO 16144 --- [ restartedMain] n.x.sample.boot.basicweb.AppApplication : Starting AppApplication using Java 11.0.8 on DESKTOP-CGD1N1Q with PID 16144 (C:\dev\proj\my\code-sample\be\java\fw\spring-boot\basic-web\target\classes started by xiaog in C:\dev\proj\my\code-sample\be\java\fw\spring-boot\basic-web)
2020-11-28 10:54:18.423 INFO 16144 --- [ restartedMain] n.x.sample.boot.basicweb.AppApplication : No active profile set, falling back to default profiles: default
2020-11-28 10:54:18.453 INFO 16144 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2020-11-28 10:54:18.453 INFO 16144 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2020-11-28 10:54:19.024 INFO 16144 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2020-11-28 10:54:19.031 INFO 16144 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2020-11-28 10:54:19.032 INFO 16144 --- [ restartedMain] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.39]
2020-11-28 10:54:19.096 INFO 16144 --- [ restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2020-11-28 10:54:19.098 INFO 16144 --- [ restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 644 ms
2020-11-28 10:54:19.208 INFO 16144 --- [ restartedMain] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2020-11-28 10:54:19.254 INFO 16144 --- [ restartedMain] o.s.b.a.w.s.WelcomePageHandlerMapping : Adding welcome page: class path resource [static/index.html]
2020-11-28 10:54:19.314 INFO 16144 --- [ restartedMain] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729
2020-11-28 10:54:19.337 INFO 16144 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2020-11-28 10:54:19.346 INFO 16144 --- [ restartedMain] n.x.sample.boot.basicweb.AppApplication : Started AppApplication in 1.216 seconds (JVM running for 1.887)
日志信息非常丰富当然是有助于我们理解应用运行的各个方面, 但经常地, 我们也不难发现一些不方便的地方, 比如就以上述的输出为例, 前面一大堆的 布局(layout) 相关的输出就极为冗长, 而真正关心的信息却被挤在了后面, 如果你的显示屏不够宽, 这些关键的信息常常反而看不到, 需要横向滚动, 非常繁琐.
下面将介绍一种极简的日志布局方案, 如下所示:
{spring.web.resources.chain.cache=false, spring.web.resources.cache.period=0}
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.4.0)
49:20 Starting AppApplication using Java 11.0.8 on DESKTOP-CGD1N1Q with PID 11800 (C:\dev\proj\my\code-sample\be\java\fw\spring-boot\basic-web\target\classes started by xiaog in C:\dev\proj\my\code-sample\be\java\fw\spring-boot\basic-web)
49:20 No active profile set, falling back to default profiles: default
49:20 Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
49:20 For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
49:20 Tomcat initialized with port(s): 8080 (http)
49:21 Starting service [Tomcat]
49:21 Starting Servlet engine: [Apache Tomcat/9.0.39]
49:21 Initializing Spring embedded WebApplicationContext
49:21 Root WebApplicationContext: initialization completed in 636 ms
49:21 Initializing ExecutorService 'applicationTaskExecutor'
49:21 Adding welcome page: class path resource [static/index.html]
49:21 LiveReload server is running on port 35729
49:21 Tomcat started on port(s): 8080 (http) with context path ''
49:21 Started AppApplication in 1.219 seconds (JVM running for 1.945)
可以看到, 仅仅输出了一个时间(分别是分钟数和秒数, 小时, 毫秒什么的都省略了), 然后就是关键的日志信息, 非常简洁, 一目了然, 基本不需要各种拓宽或横向拖动来显示.
下面说说怎么配置以达到上述效果.