java之覆盖运行时 SLF4J 绑定(bind)以进行测试_编程设计

我正在写一个包。我需要 slf4j-log4j12 以及运行时的特定附加程序。但是对于测试，我只需要一个 slf4j-simple 绑定(bind)。所以，我的 pom.xml 看起来像这样:

<?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> 
 
    <properties> 
        <maven.compiler.target>1.8</maven.compiler.target> 
        <maven.compiler.source>1.8</maven.compiler.source> 
    </properties> 
 
    <groupId>com.bharani</groupId> 
    <artifactId>LoggingDemo</artifactId> 
    <version>1.0-SNAPSHOT</version> 
 
    <dependencies> 
        <!-- Direct dependencies --> 
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api --> 
        <dependency> 
            <groupId>org.slf4j</groupId> 
            <artifactId>slf4j-api</artifactId> 
            <version>1.7.25</version> 
        </dependency> 
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 --> 
        <dependency> 
            <groupId>org.slf4j</groupId> 
            <artifactId>slf4j-log4j12</artifactId> 
            <version>1.7.25</version> 
            <scope>runtime</scope> 
        </dependency> 
 
        <!-- Test dependencies --> 
        <!-- https://mvnrepository.com/artifact/junit/junit --> 
        <dependency> 
            <groupId>junit</groupId> 
            <artifactId>junit</artifactId> 
            <version>4.12</version> 
            <scope>test</scope> 
        </dependency> 
        <!-- https://mvnrepository.com/artifact/org.assertj/assertj-core --> 
        <dependency> 
            <groupId>org.assertj</groupId> 
            <artifactId>assertj-core</artifactId> 
            <version>3.8.0</version> 
            <scope>test</scope> 
        </dependency> 
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-simple --> 
        <dependency> 
            <groupId>org.slf4j</groupId> 
            <artifactId>slf4j-simple</artifactId> 
            <version>1.7.25</version> 
            <scope>test</scope> 
        </dependency> 
    </dependencies> 
 
</project>

当我运行我的程序时，我得到了预期的 log4j 日志。但是当我运行测试时，我得到:

SLF4J: Class path contains multiple SLF4J bindings. 
SLF4J: Found binding in [jar:file:/Users/bharani/.m2/repository/org/slf4j/slf4j-log4j12/1.7.25/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class] 
SLF4J: Found binding in [jar:file:/Users/bharani/.m2/repository/org/slf4j/slf4j-simple/1.7.25/slf4j-simple-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class] 
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation. 
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]

...而且我没有在 slf4j-simple 绑定(bind)中按预期在控制台中看到日志。

我该如何解决这个问题？如何让 runtime 对 slf4j-log4j12 的依赖远离测试？

谢谢。

请您参考如下方法:

问题是 runtime 范围的依赖项也包含在测试类路径中，因此 SLF4J 最终有两个绑定(bind)并且必须选择其中一个(它选择的绑定(bind)可能是随机的，碰巧它在你的情况下选择了 log4j)。

一个简单的解决方案是从 Surefire 插件的类路径中删除 log4j 绑定(bind):

<build> 
  <plugins> 
    <plugin> 
      <groupId>org.apache.maven.plugins</groupId> 
      <artifactId>maven-surefire-plugin</artifactId> 
      <version>2.20.1</version> 
      <configuration> 
        <classpathDependencyExcludes> 
          <classpathDependencyExcludes>org.slf4j:slf4j-log4j12</classpathDependencyExcludes> 
        </classpathDependencyExcludes> 
      </configuration> 
    </plugin> 
  </plugins> 
</build>