为什么我不能加载org.slf4j.impl.StaticLoggerBinder类

编程问答 2022-08-23

问题描述

我正在Akka上一个视频课程，但是无法正常运行日志记录。我使用IntelliJ。我已经尝试了不同版本的slf4j ...，我有pom.xml 

<?xml version="1.0" encoding="UTF-8"?>
<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>org.example</groupId>
<artifactId>AkkaPrime2</artifactId>
<version>1.0-SNAPSHOT</version>

<properties>
    <akka.version>2.6.8</akka.version>
    <scala.version>2.13</scala.version>
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-actor-typed_2.13</artifactId>
        <version>${akka.version}</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.typesafe.akka/akka-actor-testkit-typed -->
    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-actor-testkit-typed_2.13</artifactId>
        <version>${akka.version}</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-classic -->
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.2.2</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
        <version>5.6.2</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>5.6.2</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.7.25</version>
    </dependency>
</dependencies>
</project>

并且代码使用的是“常规” akka方法。

代码运行后：

.onAnyMessage(message ->{
  System.out.println("I received the message : " + message);
  return this;
})

可以，但是我可以

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (nop) logger implementation

（和日志消息）

之后将执行此代码

.onMessageEquals("create a child",() -> {
  ActorRef<String> secondActor = getContext().spawn(FirstSimpleBehavior.create(),"second actor");
  secondActor.tell("who are you");
  return this;
})

但是控制台显示：

SLF4J: Failed to load class "org.slf4j.impl.StaticMDCBinder".
SLF4J: Defaulting to no-operation MDCAdapter implementation.

解决方法

我发现方法 spawn（）不接受我的第二个参数，因为它包含一个空格（我在视频中错过了）。在途中发现Logback已经包含slf4j（link），因此我从pom中删除了（slf4j）。

我摆弄pom，所以现在更改了logback的版本...但是pom现在是：

<?xml version="1.0" encoding="UTF-8"?>
<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>org.example</groupId>
<artifactId>AkkaPrime2</artifactId>
<version>1.0-SNAPSHOT</version>

<properties>
    <akka.version>2.6.8</akka.version>
    <scala.version>2.13</scala.version>
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-actor-typed_2.13</artifactId>
        <version>${akka.version}</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.typesafe.akka/akka-actor-testkit-typed -->
    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-actor-testkit-typed_2.13</artifactId>
        <version>${akka.version}</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-classic -->
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.1.9</version>
        <!--scope>test</scope-->
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
        <version>5.6.2</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>5.6.2</version>
        <scope>test</scope>
    </dependency>
</dependencies>
</project>

在baeldung.com上没有“ scope”标签，因此我不使用（我也不知道为什么要使用它）。

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