如何在最新版本的 log4j 2 中使用 commons-logging api

How to use commons-logging api with the latest version of log4j 2

我想在 log4j 2 中使用 commons-logging API。

我的类有以下代码获取记录器(commons-logging api)

package com.example.testwebapp;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


public class Log4j2ConfigBuilder {
  
  public static void main(String[] args) { 
    getLog().debug("DEBUG log entryc 11111 ");
    getLog().info("INFO log entry ");
    getLog().error("ERROR log entry ");
    getLog().warn("#############  WAR log entry ");
  }

  /**
   * @return The logger for the class.
   */
  private static Log getLog() {
    return LogFactory.getLog(Log4j2ConfigBuilder.class);
  }
}

我遇到了类似于以下问题中描述的问题:

所以简短的问题是什么是我必须使用的 maven 依赖项,才能使 commons-logging api 与最新版本的 log4j2

一起工作

以下是我的非工作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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>TestWebApp</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>TestWebApp</name>
    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.target>1.8</maven.compiler.target>
        <maven.compiler.source>1.8</maven.compiler.source>
        <junit.version>5.7.1</junit.version>
        <log4j.version>2.17.0</log4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.3.1</version>
            </plugin>
        </plugins>
    </build>
</project>

vanilla Commons Logging 有一个它可以发现的固定日志记录实现列表(参见 documentation)。 Log4j1.x在其中,但Log4j2.x不在

因此您需要将 Log4j Commons Logging Adapter 添加到您的类路径中:

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-jcl</artifactId>
    <version>${log4j.version}</version>
</dependency>

在幕后,这包含 LogFactory, which will be automatically discovered and used through the ServiceLoader 机制的替代实现。