类路径包含多个SLF4J绑定错误

Question

尝试运行gradle build时出现此错误

我理解这是一个版本冲突，但不确定如何解决它，以及

要排除的版本...

gradle依赖树是：

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/i/.gradle/caches/modules-
2/files-2.1/org.slf4j/slf4j- 
log4j12/1.6.1/bd245d6746cdd4e6203e976e21d597a46f115802/slf4j-log4j12-
1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in   
[jar:file:/C:/Users/i/.gradle/caches/modules-2/files-
2.1/ch.qos.logback/logback- 
classic/1.1.3/d90276fff414f06cb375f2057f6778cd63c6082f/logback-classic-
1.1.3.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]
SLF4J: Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class    
path, preempting StackOverflowError. 


 compile - Compile classpath for source set 'main'.
 +--- com.google.code.gson:gson:2.2.4
 +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-databind:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 |    \--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 +--- com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 |    \--- org.yaml:snakeyaml:1.15
 +--- org.projectlombok:lombok:1.16.10
 +--- javax.validation:validation-api:1.1.0.Final
 +--- org.apache.commons:commons-lang3:3.4
 +--- org.apache.zookeeper:zookeeper:3.4.5
 |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    +--- org.slf4j:slf4j-log4j12:1.6.1
 |    |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    |    \--- log4j:log4j:1.2.16
 |    +--- log4j:log4j:1.2.15 -> 1.2.16
 |    +--- jline:jline:0.9.94
 |    |    \--- junit:junit:3.8.1
 |    \--- org.jboss.netty:netty:3.2.2.Final
 +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
 +--- org.apache.httpcomponents:httpclient:4.5.3
 |    +--- org.apache.httpcomponents:httpcore:4.4.6
 |    +--- commons-logging:commons-logging:1.2
 |    \--- commons-codec:commons-codec:1.9
 +--- commons-io:commons-io:2.5
 +--- org.jdom:jdom2:2.0.5
 \--- org.slf4j:slf4j-api:1.7.21

 default - Configuration for default artifacts.
 +--- com.google.code.gson:gson:2.2.4
 +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-databind:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 |    \--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 +--- com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 |    \--- org.yaml:snakeyaml:1.15
 +--- org.projectlombok:lombok:1.16.10
 +--- javax.validation:validation-api:1.1.0.Final
 +--- org.apache.commons:commons-lang3:3.4
 +--- org.apache.zookeeper:zookeeper:3.4.5
 |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    +--- org.slf4j:slf4j-log4j12:1.6.1
 |    |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    |    \--- log4j:log4j:1.2.16
 |    +--- log4j:log4j:1.2.15 -> 1.2.16
 |    +--- jline:jline:0.9.94
 |    |    \--- junit:junit:3.8.1
 |    \--- org.jboss.netty:netty:3.2.2.Final
 +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
 +--- org.apache.httpcomponents:httpclient:4.5.3
 |    +--- org.apache.httpcomponents:httpcore:4.4.6
 |    +--- commons-logging:commons-logging:1.2
 |    \--- commons-codec:commons-codec:1.9
 +--- commons-io:commons-io:2.5
 +--- org.jdom:jdom2:2.0.5
 \--- org.slf4j:slf4j-api:1.7.21

 runtime - Runtime classpath for source set 'main'.
 +--- com.google.code.gson:gson:2.2.4
 +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-databind:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 |    \--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 +--- com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 |    \--- org.yaml:snakeyaml:1.15
 +--- org.projectlombok:lombok:1.16.10
 +--- javax.validation:validation-api:1.1.0.Final
 +--- org.apache.commons:commons-lang3:3.4
 +--- org.apache.zookeeper:zookeeper:3.4.5
 |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    +--- org.slf4j:slf4j-log4j12:1.6.1
 |    |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    |    \--- log4j:log4j:1.2.16
 |    +--- log4j:log4j:1.2.15 -> 1.2.16
 |    +--- jline:jline:0.9.94
 |    |    \--- junit:junit:3.8.1
 |    \--- org.jboss.netty:netty:3.2.2.Final
 +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
 +--- org.apache.httpcomponents:httpclient:4.5.3
 |    +--- org.apache.httpcomponents:httpcore:4.4.6
 |    +--- commons-logging:commons-logging:1.2
 |    \--- commons-codec:commons-codec:1.9
 +--- commons-io:commons-io:2.5
 +--- org.jdom:jdom2:2.0.5
 \--- org.slf4j:slf4j-api:1.7.21

 testCompile - Compile classpath for source set 'test'.
 +--- com.google.code.gson:gson:2.2.4
 +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-databind:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 |    \--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 +--- com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 |    \--- org.yaml:snakeyaml:1.15
 +--- org.projectlombok:lombok:1.16.10
 +--- javax.validation:validation-api:1.1.0.Final
 +--- org.apache.commons:commons-lang3:3.4
 +--- org.apache.zookeeper:zookeeper:3.4.5
 |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    +--- org.slf4j:slf4j-log4j12:1.6.1
 |    |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    |    \--- log4j:log4j:1.2.16
 |    +--- log4j:log4j:1.2.15 -> 1.2.16
 |    +--- jline:jline:0.9.94
 |    |    \--- junit:junit:3.8.1 -> 4.11
 |    |         \--- org.hamcrest:hamcrest-core:1.3
 |    \--- org.jboss.netty:netty:3.2.2.Final
 +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
 +--- org.apache.httpcomponents:httpclient:4.5.3
 |    +--- org.apache.httpcomponents:httpcore:4.4.6
 |    +--- commons-logging:commons-logging:1.2
 |    \--- commons-codec:commons-codec:1.9
 +--- commons-io:commons-io:2.5
 +--- org.jdom:jdom2:2.0.5
 +--- org.slf4j:slf4j-api:1.7.21
 \--- junit:junit:4.11 (*)

 testRuntime - Runtime classpath for source set 'test'.
 +--- com.google.code.gson:gson:2.2.4
 +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-databind:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 |    \--- com.fasterxml.jackson.core:jackson-core:2.6.0
 +--- com.fasterxml.jackson.core:jackson-annotations:2.6.0
 +--- com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.6.0
 |    +--- com.fasterxml.jackson.core:jackson-core:2.6.0
 |    \--- org.yaml:snakeyaml:1.15
 +--- org.projectlombok:lombok:1.16.10
 +--- javax.validation:validation-api:1.1.0.Final
 +--- org.apache.commons:commons-lang3:3.4
 +--- org.apache.zookeeper:zookeeper:3.4.5
 |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    +--- org.slf4j:slf4j-log4j12:1.6.1
 |    |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    |    \--- log4j:log4j:1.2.16
 |    +--- log4j:log4j:1.2.15 -> 1.2.16
 |    +--- jline:jline:0.9.94
 |    |    \--- junit:junit:3.8.1 -> 4.11
 |    |         \--- org.hamcrest:hamcrest-core:1.3
 |    \--- org.jboss.netty:netty:3.2.2.Final
 +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
 +--- org.apache.httpcomponents:httpclient:4.5.3
 |    +--- org.apache.httpcomponents:httpcore:4.4.6
 |    +--- commons-logging:commons-logging:1.2
 |    \--- commons-codec:commons-codec:1.9
 +--- commons-io:commons-io:2.5
 +--- org.jdom:jdom2:2.0.5
 +--- org.slf4j:slf4j-api:1.7.21
 \--- junit:junit:4.11 (*)

但我甚至不知道该怎么读。

你能帮帮忙吗？

Answer 1

首先，SLF4J是一个简单的外观，用于各种日志框架(例如java.util.logging、logback、log4j)，允许最终用户在部署时插入所需的日志框架。

用简单的话来说是什么意思？

当您使用SLF4J时，您的代码将依赖于SLF4J提供的一个公共日志记录接口(SLF4JAPI)，另一方面，您可以将您选择的日志记录框架插入到SLF4J中，这将允许您轻松切换不同的日志记录框架。

因此，您在使用SLF4J外观时在代码中使用的所有日志记录调用都将委托给底层日志记录框架。

从插图中，您可以看到您的应用程序每次都使用一个带有不同日志框架的公共接口SLF4J API。

​

​

现在，让我们看看Gradle的输出：

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/i/.gradle/caches/modules-
2/files-2.1/org.slf4j/slf4j- 
log4j12/1.6.1/bd245d6746cdd4e6203e976e21d597a46f115802/slf4j-log4j12-
1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in   
[jar:file:/C:/Users/i/.gradle/caches/modules-2/files-
2.1/ch.qos.logback/logback- 
classic/1.1.3/d90276fff414f06cb375f2057f6778cd63c6082f/logback-classic-
1.1.3.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]
SLF4J: Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class    
path, preempting StackOverflowError. 

这是两种不同的SLF4J日志框架绑定的情况，第一种是org.slf4j/slf4j-log4j12，它是SLF4J绑定，第二种是LOG4J logging framework，它是Logback logging framework，SLFJ API的本机实现。

所以，为了解决你的问题，你需要从你的类路径中排除其中的一个。

具体地说，这里有问题的工件是org.apache.zookeeper:zookeeper:3.4.5，所以让我们排除一个日志框架：

dependencies {
    compile('org.apache.zookeeper:zookeeper:3.4.5') {
        exclude group: 'ch.qos.logback', module: 'logback-classic'
    }
    //...
}

参考：SLF4J manual

Answer 2

正如@僵尸所说，这看起来像是构建脚本类路径的问题，而不是compile或runtime配置的问题。它可能可以通过以下方式修复

buildscript {
    configurations {
        classpath {
            exclude group: 'ch.qos.logback', module: 'logback-classic'
            // OR
            exclude group: 'org.slf4j', module: 'slf4j-log4j12'
        }
    }
    dependencies { ... }
} 

Answer 3

您的依赖项zoo还包含org.slf4j:slf4j-api依赖项。所以只要排除它就行了

+--- org.apache.zookeeper:zookeeper:3.4.5
 |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21
 |    +--- org.slf4j:slf4j-log4j12:1.6.1
 |    |    +--- org.slf4j:slf4j-api:1.6.1 -> 1.7.21    # <-- dependency includes slf4j-api
 |    |    \--- log4j:log4j:1.2.16
 |    +--- log4j:log4j:1.2.15 -> 1.2.16
 |    +--- jline:jline:0.9.94
 |    |    \--- junit:junit:3.8.1
 |    \--- org.jboss.netty:netty:3.2.2.Final
 +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
 +--- org.apache.httpcomponents:httpclient:4.5.3
 |    +--- org.apache.httpcomponents:httpcore:4.4.6
 |    +--- commons-logging:commons-logging:1.2
 |    \--- commons-codec:commons-codec:1.9
 +--- commons-io:commons-io:2.5
 +--- org.jdom:jdom2:2.0.5
 +--- org.slf4j:slf4j-api:1.7.21  # <-- Also included as a first tier dependency

在您的build.gradle中，只需从zookeeper库中排除它即可。

dependencies {
    compile('org.apache.zookeeper:zookeeper:3.4.5') {
        // exclude transitive logging dependency from zookeeper
        exclude group: 'org.slf4j'
        // might need to exclude log4j, not sure?
        exclude group: 'log4j', module: 'log4j'
    }
    // .. other dependencies
}