java - Maven 执行 :java goal on a multi-module project

Question

我正在尝试在一个简单的两模块项目上运行 exec-maven-plugin 的 exec:java 目标，其中一个模块依赖于另一个模块。到目前为止，我找不到有效的配置。这是一个简化的测试用例:

+ exec-multi-module-test/
    + pom.xml
    + module1/
        + pom.xml
        + src/
            + main/
                + java/
                    + HelloPrinter.java
    + module2/
        + pom.xml
        + src/
            + main/
                + java/
                    + MyMain.java

这是父 pom:

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.mkscrg.sandbox</groupId>
    <artifactId>exec-multi-module-test</artifactId>
    <version>1.0</version>
    <packaging>pom</packaging>

    <modules>
        <module>module1</module>
        <module>module2</module>
    </modules>

    <build>
        <plugins>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.2.1</version>
            </plugin>
        </plugins>
    </build>
</project>

module1 的 pom:

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>exec-multi-module-test</artifactId>
        <groupId>com.mkscrg.sandbox</groupId>
        <version>1.0</version>
    </parent>

    <artifactId>module1</artifactId>
</project>

module2 的 pom: 4.0.0

    <parent>
        <artifactId>exec-multi-module-test</artifactId>
        <groupId>com.mkscrg.sandbox</groupId>
        <version>1.0</version>
    </parent>

    <artifactId>module2</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.mkscrg.sandbox</groupId>
            <artifactId>module1</artifactId>
            <version>${project.version}</version>
        </dependency>
    </dependencies>
</project>

此项目从顶部编译成功，但运行 mvn exec:java -Dexec.mainClass=myMain 失败:

[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO] 
[INFO] exec-multi-module-test
[INFO] module1
[INFO] module2
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building exec-multi-module-test 1.0
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] >>> exec-maven-plugin:1.2.1:java (default-cli) @ exec-multi-module-test >>>
[INFO] 
[INFO] <<< exec-maven-plugin:1.2.1:java (default-cli) @ exec-multi-module-test <<<
[INFO] 
[INFO] --- exec-maven-plugin:1.2.1:java (default-cli) @ exec-multi-module-test ---
[WARNING] 
java.lang.ClassNotFoundException: MyMain
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
        at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:285)
        at java.lang.Thread.run(Thread.java:680)
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] exec-multi-module-test ............................ FAILURE [0.363s]
[INFO] module1 ........................................... SKIPPED
[INFO] module2 ........................................... SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.566s
[INFO] Finished at: Mon Jun 18 14:11:54 PDT 2012
[INFO] Final Memory: 3M/81M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project exec-multi-module-test: An exception occured while executing the Java class. MyMain -> [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.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

配置这个项目以允许 exec:java 看到 MyMain 的正确方法是什么？

编辑:如果您想自己尝试一下，这里有一个要点:https://gist.github.com/2950830

编辑:澄清:我知道可以 mvn install 然后从 module2 的目录运行 exec:java 或使用-pl 标志从顶部。但是，我想避免运行 mvn install。无需修改我的本地存储库即可在多模块项目中运行此目标。就像 mvn compile 在多模块项目中“正常工作”一样，其他目标/阶段也应该如此。

Answer 1

多模块项目中的目标在从父级运行时，将针对所有模块运行。我不认为那是你想要的。你可以试试:

mvn exec:java -pl module2 -Dexec.mainClass=MyMain

这可能有用吗？更多信息:

• Running a specific Maven plugin goal from the command line in a sub-module of a multi-module reactor project

但是，我认为在运行之前将目录更改为包含可执行文件的子模块更直观。