Maven打包JavaFX应用时Main-Class未写入MANIFEST.MF求助

问题现象 #

执行java -jar BadDDOS-1.0-SNAPSHOT.jar时提示：

no main manifest attribute, in BadDDOS-1.0-SNAPSHOT.jar

打包后的Jar内MANIFEST.MF缺少Main-Class属性，内容如下：

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven 3.8.5
Built-By: Jason
Build-Jdk: 21.0.2

Jar结构确认包含主类文件（me/jason/badddos/Application.class），完整结构：

META-INF/
META-INF/MANIFEST.MF
me/
me/jason/
me/jason/badddos/
me/jason/badddos/css/
me/jason/badddos/fxml/
me/jason/badddos/misc/
me/jason/badddos/skins/
me/jason/badddos/Application.class
me/jason/badddos/css/home-style.css
me/jason/badddos/DDOS.class
me/jason/badddos/fxml/home-view.fxml
me/jason/badddos/Home_Controller.class
me/jason/badddos/misc/shrek.jpg
me/jason/badddos/skins/ddosBtn_Skin.class
module-info.class
META-INF/maven/
META-INF/maven/me.jason/
META-INF/maven/me.jason/BadDDOS/
META-INF/maven/me.jason/BadDDOS/pom.xml
META-INF/maven/me.jason/BadDDOS/pom.properties

配置情况 #

已在pom.xml的javafx-maven-plugin中配置<mainClass>me.jason.badddos.Application</mainClass>，完整pom.xml内容：

<?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>me.jason</groupId>
  <artifactId>BadDDOS</artifactId>
  <version>1.0-SNAPSHOT</version>
  <name>BadDDOS</name>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<junit.version>5.10.0</junit.version>  </properties>

  <dependencies>
    <dependency>
      <groupId>com.github.akman</groupId>
      <artifactId>jpackage-maven-plugin</artifactId>
      <version>0.1.5</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-controls</artifactId>
      <version>21</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-fxml</artifactId>
      <version>21</version>
    </dependency>
    <dependency>
      <groupId>org.controlsfx</groupId>
      <artifactId>controlsfx</artifactId>
      <version>11.1.2</version>
    </dependency>
    <dependency>
      <groupId>org.kordamp.ikonli</groupId>
      <artifactId>ikonli-javafx</artifactId>
      <version>12.3.1</version>
    </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>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.11.0</version>
        <configuration>
          <source>21</source>
          <target>21</target>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.openjfx</groupId>
        <artifactId>javafx-maven-plugin</artifactId>
        <version>0.0.8</version>
        <executions>
          <execution>
            <id>default-cli</id>
            <configuration>
              <mainClass>me.jason.badddos.Application</mainClass>
              <launcher>app</launcher>
              <jlinkZipName>app</jlinkZipName>
              <jlinkImageName>app</jlinkImageName>
              <noManPages>true</noManPages>
              <stripDebug>true</stripDebug>
              <noHeaderFiles>true</noHeaderFiles>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

原因分析 #

javafx-maven-plugin的默认执行目标是javafx:run，仅用于运行应用，不会负责生成包含Main-Class的可执行Jar。当前打包操作实际是maven-jar-plugin的默认jar目标完成的，而该插件未配置主类信息，因此生成的Jar没有Main-Class属性。

解决方案 #

方案1：配置maven-jar-plugin添加主类信息 #

在pom.xml的<build><plugins>中添加maven-jar-plugin配置，指定主类：

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-jar-plugin</artifactId>
  <version>3.3.0</version>
  <configuration>
    <archive>
      <manifest>
        <mainClass>me.jason.badddos.Application</mainClass>
        <addClasspath>true</addClasspath>
      </manifest>
    </archive>
  </configuration>
</plugin>

注意：这种方式生成的Jar需要依赖JavaFX运行时环境，运行时需确保JavaFX库在类路径中，或使用--module-path指定JavaFX模块路径。

方案2：使用javafx-maven-plugin生成可执行Jar #

修改javafx-maven-plugin的配置，添加javafx:jar执行目标，该目标会生成包含JavaFX依赖的可执行Jar：

<plugin>
  <groupId>org.openjfx</groupId>
  <artifactId>javafx-maven-plugin</artifactId>
  <version>0.0.8</version>
  <executions>
    <execution>
      <id>default-cli</id>
      <configuration>
        <mainClass>me.jason.badddos.Application</mainClass>
        <launcher>app</launcher>
        <jlinkZipName>app</jlinkZipName>
        <jlinkImageName>app</jlinkImageName>
        <noManPages>true</noManPages>
        <stripDebug>true</stripDebug>
        <noHeaderFiles>true</noHeaderFiles>
      </configuration>
    </execution>
    <execution>
      <id>default-jar</id>
      <goals>
        <goal>jar</goal>
      </goals>
      <configuration>
        <mainClass>me.jason.badddos.Application</mainClass>
      </configuration>
    </execution>
  </executions>
</plugin>

执行打包命令：mvn clean package，生成的Jar会包含Main-Class属性，且内置JavaFX依赖。

方案3：使用jlink生成模块化运行镜像（推荐） #

如果项目是模块化项目（存在module-info.class），可以使用javafx-maven-plugin的jlink目标生成独立的运行镜像，无需依赖系统JavaFX环境：

<plugin>
  <groupId>org.openjfx</groupId>
  <artifactId>javafx-maven-plugin</artifactId>
  <version>0.0.8</version>
  <executions>
    <execution>
      <id>default-cli</id>
      <configuration>
        <mainClass>me.jason.badddos.Application</mainClass>
        <launcher>app</launcher>
        <jlinkZipName>app</jlinkZipName>
        <jlinkImageName>app</jlinkImageName>
        <noManPages>true</noManPages>
        <stripDebug>true</stripDebug>
        <noHeaderFiles>true</noHeaderFiles>
      </configuration>
      <goals>
        <goal>jlink</goal>
      </goals>
    </execution>
  </executions>
</plugin>

执行命令：mvn clean javafx:jlink，生成的app目录中包含可执行启动脚本，直接运行即可。

内容的提问来源于stack exchange，提问作者crjase