Akka中使用Logback日志框架

Akka提供的默认日志系统只输出到控制台，这种日志系统不可以用到产品环境，当然你可以整合SLF4J这样的日志系统，下面介绍如何在Akka中使用Logback记录日志。

1. 创建Maven工程引入相关依赖。

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.shindler.ioee.test</groupId>
  <artifactId>akka</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>akka</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.typesafe.akka/akka-actor_2.11 -->
    <dependency>
      <groupId>com.typesafe.akka</groupId>
      <artifactId>akka-actor_2.11</artifactId>
      <version>2.4.10</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.typesafe.akka/akka-slf4j_2.11 -->
    <dependency>
      <groupId>com.typesafe.akka</groupId>
      <artifactId>akka-slf4j_2.11</artifactId>
      <version>2.4.10</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-classic -->
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.1.7</version>
    </dependency>
  </dependencies>
</project>

2. 添加akka配置文件，指定使用SLF4J日志系统。

# In this file you can override any option defined in the reference files.
# Copy in parts of the reference files and modify as you please.

akka {

  # Loggers to register at boot time (akka.event.Logging$DefaultLogger logs
  # to STDOUT)
  loggers = ["akka.event.slf4j.Slf4jLogger"]

  # Log level used by the configured loggers (see "loggers") as soon
  # as they have been started; before that, see "stdout-loglevel"
  # Options: OFF, ERROR, WARNING, INFO, DEBUG
  loglevel = "ERROR"

  # Log level for the very basic logger activated during ActorSystem startup.
  # This logger prints the log messages to stdout (System.out).
  # Options: OFF, ERROR, WARNING, INFO, DEBUG
  stdout-loglevel = "ERROR"

  # Filter of log events that is used by the LoggingAdapter before
  # publishing log events to the eventStream.
  logging-filter = "akka.event.slf4j.Slf4jLoggingFilter"

}

3. 创建Logback.xml配置文件，产品环境中，会单独记录错误日志，配置如下：

<configuration>
    <!--ERROR与其他日志分开-->
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>ERROR</level>
            <onMatch>DENY</onMatch>
            <onMismatch>ACCEPT</onMismatch>
        </filter>
        <encoder>
            <pattern>
                <pattern>CONSOLE -- [%-5level] %d{HH:mm:ss} - %msg%n</pattern>
            </pattern>
        </encoder>
    </appender>

    <!--ERROR与其他日志分开-->
    <appender name="ERROR" class="ch.qos.logback.core.ConsoleAppender">
        <target>System.err</target>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>ERROR</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <encoder>
            <pattern>
                <pattern>ERROR -- [%-5level] %d{HH:mm:ss} - %msg%n</pattern>
            </pattern>
        </encoder>
    </appender>

    <root level="DEBUG">
        <appender-ref ref="CONSOLE" />
        <appender-ref ref="ERROR" />
    </root>
</configuration>

4. 创建LoggerActor类，代码如下：

package com.shindler.ioee.test;

import akka.actor.UntypedActor;
import akka.event.Logging;
import akka.event.LoggingAdapter;
import scala.Option;

/**
 * Created by zengsam on 2016/9/29.
 */
public class LoggerActor2 extends UntypedActor {
    LoggingAdapter log = Logging.getLogger(getContext().system(), this);

    @Override
    public void onReceive(Object message) throws Throwable {
        log.error("Received message: {}", message);
        log.info("Received message: {}", message);
        log.debug("Received message: {}", message);
    }

    @Override
    public void preStart() {
        log.info("Starting");
    }

    @Override
    public void preRestart(Throwable reason, Option<Object> message) {
        log.error(reason, "Restarting due to [{}] when processing [{}]",
                reason.getMessage(), message.isDefined() ? message.get() : "");
    }
}

5. 创建测试程序，代码如下：

package com.shindler.ioee.test;

import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.Props;
import java.util.Date;

/**
 * Hello world!
 */
public class App {
    public static void main(String[] args) {
        System.out.println("Hello World!");

        ActorSystem system = ActorSystem.apply("testActorSystem");
        ActorRef loggerActor = system.actorOf(Props.create(LoggerActor.class), "loggerActor");
        ActorRef loggerActor2 = system.actorOf(Props.create(LoggerActor2.class), "loggerActor2");
        while (true) {
            try {
                loggerActor.tell(new Date().toString(), ActorRef.noSender());
                loggerActor2.tell(new Date().toString(), ActorRef.noSender());
                Thread.sleep(1000);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

运行程序，可以看到Actor使用了Logback来记录日志，并且单独记录了ERROR日志。