为什么 Maven 看不到 JavaFX 图形模块（而 Eclipse 有）答案

【问题标题】：Why does Maven not see JavaFX graphics module (while Eclipse does)为什么 Maven 看不到 JavaFX 图形模块（而 Eclipse 有）
【发布时间】：2020-02-11 12:30:38
【问题描述】：

我有一个多模块 Maven 项目，其中一个模块使用 JavaFX。虽然在 Eclipse 中一切都编译得很好，但做一个

mvn 干净编译

返回此错误

package javafx.scene.robot does not exist

似乎 maven 看不到包含 javafx.scene.robot 的 javafx.graphics 模块（但 Eclipse 确实看到了它，因为它没有给出编译错误）。如何让 Maven 编译这段代码？

我创建了一个迷你版的应用程序来重现这一点。这些是文件：

主 pom.xml

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>nl.eddy</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <release>11</release>   <!-- JDK Version -->
                </configuration>
            </plugin>
        </plugins>
    </build>

    <modules>
        <module>mod1</module>
    </modules>
</project>

模块 pom.xml

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>nl.eddy</groupId>
        <artifactId>demo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <artifactId>mod1</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>11.0.2</version>
        </dependency>
    </dependencies>

</project>

Launch.java

package nl.eddy.mod1;

import javafx.application.Application;
import javafx.scene.robot.Robot;
import javafx.stage.Stage;

public class Launch extends Application{

    public static void main(String[] args) {

    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        new Robot();
    }

}

模块信息.java

module nl.eddy.mod1 {

    requires javafx.controls;
//  requires javafx.graphics; uncommenting this does not change maven's message
}

mvn clean compile 的输出

[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /C:/Users/egr/eclipse-workspace/demo/mod1/src/main/java/nl/eddy/mod1/Launch.java:[4,26] package javafx.scene.robot does not exist
[ERROR] /C:/Users/egr/eclipse-workspace/demo/mod1/src/main/java/nl/eddy/mod1/Launch.java:[15,21] cannot find symbol
  symbol:   class Robot
  location: class nl.eddy.mod1.Launch
[INFO] 2 errors
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for demo 0.0.1-SNAPSHOT:
[INFO]
[INFO] demo ............................................... SUCCESS [  0.368 s]
[INFO] mod1 ............................................... FAILURE [  2.541 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.161 s
[INFO] Finished at: 2020-02-11T13:08:56+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project mod1: Compilation failure: Compilation failure:
[ERROR] /C:/Users/egr/eclipse-workspace/demo/mod1/src/main/java/nl/eddy/mod1/Launch.java:[4,26] package javafx.scene.robot does not exist
[ERROR] /C:/Users/egr/eclipse-workspace/demo/mod1/src/main/java/nl/eddy/mod1/Launch.java:[15,21] cannot find symbol
[ERROR]   symbol:   class Robot
[ERROR]   location: class nl.eddy.mod1.Launch
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.

来自mvn -X compile日志的编译器详情

Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T20:41:47+02:00)
Maven home: C:\apps\apache-maven-3.6.0\bin\..
Java version: 12.0.2, vendor: Oracle Corporation, runtime: C:\Program Files\Java\jdk-12.0.2
Default locale: en_US, platform encoding: Cp1252
OS name: "windows server 2012 r2", version: "6.3", arch: "amd64", family: "windows"

【问题讨论】：

你编译的时候用的是什么JDK？（运行mvn -X compile 找出答案）
@JoséPereda 我已经在上面的帖子中添加了mvn -X compile 输出的开头。
我无法重现您的问题。确保%PATH% 中没有任何其他 JDK，因为 Maven 会选择它。您也可以尝试添加到编译器插件配置：<executable>/path/to/javac</executable><fork>true</fork>，其中路径指向上面的 JDK 12.0.2
@JoséPereda 感谢您向我指出编译器插件配置。我只需要将版本更改为 12，它是 11。

标签： java maven javafx java-module

【解决方案1】：

只要我将 maven-compiler-plugin 发布元素更改为值 12 而不是 11，编译就会正常进行。即，与实际运行 Maven 的编译器的值相同。非常感谢@JosePereda，请参阅 cmets。

【讨论】：