Maven构建后运行Jar报NoClassDefFoundError: org/slf4j/LoggerFactory

执行mvn clean install构建项目后，运行java -jar target/Sorting-1.0-SNAPSHOT.jar时抛出如下错误：

Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
    at xyz.skwar.sorting.Main.<clinit>(Main.java:7)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
    ... 1 more

已尝试以下操作但未解决：

• 引入logback-classic而非仅SLF4J API
• 参考多篇技术文章及Stack Overflow帖子（其中第4个方案无效，第5个场景不符，未设置依赖scope）
• 移除slf4j-api依赖（按SLF4J文档说明，logback-classic已包含该依赖），但运行出现提示：

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.

编写最小复现代码仍存在问题：

package xyz.skwar.sorting;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Main {
  private static final Logger logger = LoggerFactory.getLogger(Main.class);

  public static void main(String[] args) {
    logger.info("test");
  }
}

完整pom.xml文件：

<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>xyz.skwar.sorting</groupId>
  <artifactId>Sorting</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <maven.compiler.source>20</maven.compiler.source>
    <maven.compiler.target>20</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <org.slf4j.version>2.0.9</org.slf4j.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.30</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.testng</groupId>
      <artifactId>testng</artifactId>
      <version>7.8.0</version>
    </dependency>
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.4.11</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>${org.slf4j.version}</version>
    </dependency>
  </dependencies>
  <pluginRepositories>
    <pluginRepository>
      <releases>
        <updatePolicy>never</updatePolicy>
      </releases>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Central Repository</name>
      <url>https://repo.maven.apache.org/maven2</url>
    </pluginRepository>
  </pluginRepositories>
  <build>
    <plugins>
      <plugin>
        <!-- Build an executable JAR -->
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.1.0</version>
        <configuration>
          <archive>
            <manifest>
              <addClasspath>true</addClasspath>
              <classpathPrefix>lib/</classpathPrefix>
              <mainClass>xyz.skwar.sorting.Main</mainClass>
            </manifest>
          </archive>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

核心问题是生成的可执行Jar未包含依赖包：maven-jar-plugin仅打包项目自身代码，不会将SLF4J、Logback等依赖Jar包打包进去，也不会自动把依赖包复制到配置的lib目录下。

以下是两种常用解决方式：

方式一：生成包含所有依赖的Fat Jar（推荐） #

使用maven-shade-plugin替换或补充现有插件，它会将所有依赖合并到一个Jar中，直接运行即可：

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-shade-plugin</artifactId>
      <version>3.4.1</version>
      <executions>
        <execution>
          <phase>package</phase>
          <goals>
            <goal>shade</goal>
          </goals>
          <configuration>
            <transformers>
              <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                <mainClass>xyz.skwar.sorting.Main</mainClass>
              </transformer>
            </transformers>
          </configuration>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

执行mvn clean package后，直接运行java -jar target/Sorting-1.0-SNAPSHOT.jar即可。

方式二：复制依赖到lib目录并保持原Jar结构 #

保留原maven-jar-plugin配置，添加maven-dependency-plugin将依赖复制到target/lib目录：

<build>
  <plugins>
    <plugin>
      <!-- 原有的maven-jar-plugin配置 -->
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-jar-plugin</artifactId>
      <version>3.1.0</version>
      <configuration>
        <archive>
          <manifest>
            <addClasspath>true</addClasspath>
            <classpathPrefix>lib/</classpathPrefix>
            <mainClass>xyz.skwar.sorting.Main</mainClass>
          </manifest>
        </archive>
      </configuration>
    </plugin>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-dependency-plugin</artifactId>
      <version>3.6.0</version>
      <executions>
        <execution>
          <phase>package</phase>
          <goals>
            <goal>copy-dependencies</goal>
          </goals>
          <configuration>
            <outputDirectory>${project.build.directory}/lib</outputDirectory>
          </configuration>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

执行mvn clean package后，target目录会生成lib文件夹和原Jar包，直接运行java -jar target/Sorting-1.0-SNAPSHOT.jar即可，Manifest中的classpath会自动指向lib目录下的依赖。

额外说明 #

logback-classic确实已包含slf4j-api，因此可以移除pom中单独的slf4j-api依赖，避免潜在版本冲突（当前logback-classic 1.4.11依赖的slf4j-api版本为2.0.9，与你配置的版本一致，移除后更简洁）。

内容的提问来源于stack exchange，提问作者benni347