slf4j找不到log4j2罐子 [英] slf4j does not find log4j2 jars

问题描述

我知道将 SLF4J 与Log4j2作为记录器实现一起使用应该很容易.

I know it should be easy to use SLF4J with Log4j2 as logger implementation.

您只需要将jar添加到类路径中即可.

You just need to add the jars to the classpath.

我以为我这样做了，但是我还是得到了

I have thought that I did so, but I am still getting

INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

我的 pom.xml

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.30</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j18-impl</artifactId>
    <version>2.14.0</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.14.0</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.14.0</version>
    <scope>runtime</scope>
</dependency>

然后摘录自 .classpath

<classpathentry kind="var" path="M2_REPO/org/slf4j/slf4j-api/1.7.30/slf4j-api-1.7.30.jar" sourcepath="M2_REPO/org/slf4j/slf4j-api/1.7.30/slf4j-api-1.7.30-sources.jar"/>
<classpathentry kind="var" path="M2_REPO/org/apache/logging/log4j/log4j-slf4j18-impl/2.14.0/log4j-slf4j18-impl-2.14.0.jar" sourcepath="M2_REPO/org/apache/logging/log4j/log4j-slf4j18-impl/2.14.0/log4j-slf4j18-impl-2.14.0-sources.jar"/>
<classpathentry kind="var" path="M2_REPO/org/apache/logging/log4j/log4j-api/2.14.0/log4j-api-2.14.0.jar" sourcepath="M2_REPO/org/apache/logging/log4j/log4j-api/2.14.0/log4j-api-2.14.0-sources.jar"/>
<classpathentry kind="var" path="M2_REPO/org/apache/logging/log4j/log4j-core/2.14.0/log4j-core-2.14.0.jar" sourcepath="M2_REPO/org/apache/logging/log4j/log4j-core/2.14.0/log4j-core-2.14.0-sources.jar"/>

然后，在 lib 文件夹中查找

$ find ./ -name "*slf4*.jar"
./target/my-app-0.0.1-SNAPSHOT/WEB-INF/lib/log4j-slf4j18-impl-2.14.0.jar
./target/my-app-0.0.1-SNAPSHOT/WEB-INF/lib/slf4j-api-1.7.30.jar

$ find ./ -name "*log4j*.jar"
./target/my-app-0.0.1-SNAPSHOT/WEB-INF/lib/log4j-slf4j18-impl-2.14.0.jar
./target/my-app-0.0.1-SNAPSHOT/WEB-INF/lib/log4j-api-2.14.0.jar
./target/my-app-0.0.1-SNAPSHOT/WEB-INF/lib/log4j-core-2.14.0.jar

我想念什么?

我是否需要添加一个log4j2 配置xml文件?

但是我没有收到相应的错误消息.

What am I missing?

Do I need to add a log4j2 config xml file?

But I do not get the corresponding error message.

我正在使用

• Eclipse 版本:2020-09 (4.17.0)
• Apache Maven 3.6.3

和 maven-war-plugin

<plugin>
    <artifactId>maven-war-plugin</artifactId>
    <version>3.2.3</version>
    <configuration>
        <warSourceDirectory>WebContent</warSourceDirectory>
        <!-- https://stackoverflow.com/a/33390519/2092322 annotations instead of web.xml -->
        <failOnMissingWebXml>false</failOnMissingWebXml>
    </configuration>
</plugin>

推荐答案

这是因为您使用的是 slf4j 1.7.* ，但是您使用的是 logj4j-slf4j18-impl 假定与slf4j 1.8(尚未发布或更改为当前处于Alpha版本的2.0.0版本)一起使用.您需要更改

This is because you are using slf4j 1.7.* but you using logj4j-slf4j18-impl which suppose to be used with slf4j 1.8 (which doesn't released yet or change to version 2.0.0 which currently in alpha version). You need to change from

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j18-impl</artifactId>
    <version>2.14.0</version>
    <scope>runtime</scope>
</dependency>

到

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>
    <version>2.14.0</version>
    <scope>runtime</scope>
</dependency>

以使其与您在项目中使用的slf4j兼容

in order to make it compatible with slf4j that you used in your project

这篇关于slf4j找不到log4j2罐子的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！