完整的“Scala 日志记录”示例

Complete "Scala Logging" Example

提问by jans

I'm trying to use Typesafe's Scala Loggingbut couldn't get it to print any debug message. I expect Scala Logging to print debug message to the default screen but it doesn't work. A complete example would be very helpful or specific advise what to change would be great too. I use Scala 2.11. Here is what I did:

我正在尝试使用 Typesafe 的Scala Logging，但无法打印任何调试消息。我希望 Scala Logging 将调试消息打印到默认屏幕，但它不起作用。一个完整的例子会非常有帮助，或者具体建议改变什么也很好。我使用 Scala 2.11。这是我所做的：

1. I added the dependency to build.sbt:

   libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging" % "3.1.0"
   

   Even though I'm not sure if this is required, I added the following line but it didn't do any difference:

   libraryDependencies += "com.typesafe.scala-logging" % "scala-logging-slf4j_2.11" % "2.1.2"
   

2. This is how my class looks like basically:

   import com.typesafe.scalalogging._
   
   class MyClass extends LazyLogging {
     // ...
     logger.debug("Here goes my debug message.")
     // ...
   }
   

3. I discovered the file ./src/main/resources/logback.xml but am not sure which module installed it and if its relevant. I changed the log level to "debug" without effect.

   <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>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
       </encoder>
     </appender>
   
     <logger name="scala.slick" level="DEBUG"/>
   
     <root level="debug">
       <appender-ref ref="STDOUT" />
     </root>
   </configuration>
   

1. 我在 build.sbt 中添加了依赖项：

   libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging" % "3.1.0"
   

   尽管我不确定是否需要这样做，但我添加了以下行，但没有任何区别：

   libraryDependencies += "com.typesafe.scala-logging" % "scala-logging-slf4j_2.11" % "2.1.2"
   

2. 这就是我的班级基本上的样子：

   import com.typesafe.scalalogging._
   
   class MyClass extends LazyLogging {
     // ...
     logger.debug("Here goes my debug message.")
     // ...
   }
   

3. 我发现了文件 ./src/main/resources/logback.xml 但不确定哪个模块安装了它以及它是否相关。我将日志级别更改为“调试”但没有效果。

   <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>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
       </encoder>
     </appender>
   
     <logger name="scala.slick" level="DEBUG"/>
   
     <root level="debug">
       <appender-ref ref="STDOUT" />
     </root>
   </configuration>
   

采纳答案by Alexey Romanov

IIRC it'll print messages starting from info level by default. To change this, you need to put logback.xmlfile into src/main/resources(or use -Dlogback.configurationFile=/path/to/config.xmlJVM parameter). See Configurationchapter in Logback documentation.

IIRC 它将默认从信息级别开始打印消息。要更改此设置，您需要将logback.xml文件放入src/main/resources（或使用-Dlogback.configurationFile=/path/to/config.xmlJVM 参数）。请参阅Logback 文档中的配置章节。

回答by Vinay

For those who're still struggling for how to make your scala-logging work in your sbt project. They just need to follow these steps:

对于那些仍在为如何在 sbt 项目中使用 Scala 日志而苦苦挣扎的人。他们只需要遵循以下步骤：

1. Add these two dependencies in your build.sbt:

   libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging" % "3.1.0"
   libraryDependencies += "ch.qos.logback" % "logback-classic" % "1.1.2"
   

2. Create a file logback.xmlin your /src/main/resources/ and paste below mentioned content in that file.

   <configuration>
       <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
           <encoder>
               <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
           </encoder>
       </appender>
   
       <appender name="FILE" class="ch.qos.logback.core.FileAppender">
           <!-- path to your log file, where you want to store logs -->
           <file>/Users/yourusername/test.log</file>
           <append>false</append>
           <encoder>
               <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
           </encoder>
       </appender>
   
       <root level="debug">
           <appender-ref ref="STDOUT" />
           <appender-ref ref="FILE" />
       </root>
   </configuration>
   

3. Extend your Scala class or object with trait LazyLogging:

   import com.typesafe.scalalogging.slf4j.LazyLogging
   class MyClass extends LazyLogging {
     logger.debug("This is very convenient ;-)")
   }
   

4. It's done.

1. 将这两个依赖项添加到您的build.sbt：

   libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging" % "3.1.0"
   libraryDependencies += "ch.qos.logback" % "logback-classic" % "1.1.2"
   

2. 在您的 /src/main/resources/ 中创建一个文件logback.xml并将下面提到的内容粘贴到该文件中。

   <configuration>
       <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
           <encoder>
               <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
           </encoder>
       </appender>
   
       <appender name="FILE" class="ch.qos.logback.core.FileAppender">
           <!-- path to your log file, where you want to store logs -->
           <file>/Users/yourusername/test.log</file>
           <append>false</append>
           <encoder>
               <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
           </encoder>
       </appender>
   
       <root level="debug">
           <appender-ref ref="STDOUT" />
           <appender-ref ref="FILE" />
       </root>
   </configuration>
   

3. 使用 trait 扩展你的 Scala 类或对象LazyLogging：

   import com.typesafe.scalalogging.slf4j.LazyLogging
   class MyClass extends LazyLogging {
     logger.debug("This is very convenient ;-)")
   }
   

4. 完成。

P.S: Only a side note that loggeris already a member of trait LazyLogging so you don't need to create it (as shown in above example)

PS：只需要说明一下logger已经是 trait LazyLogging 的成员，所以你不需要创建它（如上例所示）

回答by Joseph Sawyer

You're close, but you have to declare a loggerinstance using an SLF4J logger in the applymethod for the Loggercompanion in com.typesafe.scalalogging. In your build.sbtinclude:

你靠近，但你必须声明logger中使用SLF4J记录器实例apply的方法Logger同伴com.typesafe.scalalogging。在您的build.sbt包括：

libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging" % "3.1.0"

libraryDependencies += "org.slf4j" % "slf4j-api" % "1.7.10"

Then this will work:

然后这将起作用：

import com.typesafe.scalalogging._
import org.slf4j.LoggerFactory

class MyClass extends LazyLogging {
  // ...
  val logger = Logger(LoggerFactory.getLogger(this.getClass))
  logger.debug("Here goes my debug message.")
  // ...
}

Hereis a reference for LoggerFactory. Hope it helps!

这是 LoggerFactory 的参考。希望能帮助到你！