问题描述
我正在使用模块系统将一些 Java 8 代码移植到 Java 11。
一个 jar 包含以下模块:
module de.powerstat.fb.generator
{
exports de.powerstat.fb.generator;
// ....
}
这是完美的工作。 现在在另一个 Maven 项目中,我在 pom 中引用了这个 jar/模块:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<includeProjectDependencies>false</includeProjectDependencies>
<includePluginDependencies>true</includePluginDependencies>
<executableDependency>
<groupId>de.powerstat.fb</groupId>
<artifactId>generator</artifactId>
</executableDependency>
<mainClass>de.powerstat.fb.generator/de.powerstat.fb.generator.CodeGenerator</mainClass>
<arguments>
<argument>${fb.hostname}</argument>
<argument>${fb.port}</argument>
<argument>${fb.username}</argument>
<argument>${fb.password}</argument>
<argument>${project.build.directory}</argument>
</arguments>
<cleanupDaemonThreads>false</cleanupDaemonThreads>
</configuration>
<executions>
<execution>
<phase>generate-sources</phase>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>de.powerstat.fb</groupId>
<artifactId>generator</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>
</plugin>
现在什么时候做
mvn clean install
这会导致 NullPointerException:
...
Caused by: java.lang.NullPointerException
at org.codehaus.mojo.exec.AbstractExecMojo.findExecutableArtifact (AbstractExecMojo.java:277)
at org.codehaus.mojo.exec.ExecJavaMojo.determineRelevantPluginDependencies (ExecJavaMojo.java:606)
at org.codehaus.mojo.exec.ExecJavaMojo.addRelevantPluginDependenciesToClasspath (ExecJavaMojo.java:539)
at org.codehaus.mojo.exec.ExecJavaMojo.getClassLoader (ExecJavaMojo.java:492)
at org.codehaus.mojo.exec.ExecJavaMojo.execute (ExecJavaMojo.java:273)
...
现在注释掉以下部分时:
<!--
<executableDependency>
<groupId>de.powerstat.fb</groupId>
<artifactId>generator</artifactId>
</executableDependency>
-->
然后错误变为:
Caused by: java.lang.module.ResolutionException: Modules xml.apis and xercesImpl export package org.w3c.dom.html to module maven.model
at java.lang.module.Resolver.resolveFail (Resolver.java:885)
at java.lang.module.Resolver.failTwosuppliers (Resolver.java:797)
at java.lang.module.Resolver.checkExportsuppliers (Resolver.java:718)
at java.lang.module.Resolver.finish (Resolver.java:362)
at java.lang.module.Configuration.<init> (Configuration.java:141)
at java.lang.module.Configuration.resolve (Configuration.java:424)
at java.lang.module.Configuration.resolve (Configuration.java:256)
at org.codehaus.mojo.exec.LoaderFinder.find (LoaderFinder.java:54)
at org.codehaus.mojo.exec.ExecJavaMojo.getClassLoader (ExecJavaMojo.java:498)
at org.codehaus.mojo.exec.ExecJavaMojo.execute (ExecJavaMojo.java:273)
所以我的问题是,我能做些什么来解决这种情况?也许我做错了什么?或者是插件中的错误?如果它是插件中的错误 - 是否有某种解决方法(因为插件看起来没有维护)?
只是让你知道 - 我在 MacOS 上使用 maven 3.6.3。
@Extension1:
今天在使用上面注释掉的代码进行编译时,我收到一条不同的错误消息:
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java (default) on project gentr64: Execution default of goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java Failed: Module sisu.inject.bean contains package org.sonatype.guice.asm,module sisu.inject.plexus exports package org.sonatype.guice.asm to sisu.inject.bean -> [Help 1]
所以它看起来更像是插件的问题,或者可能是 maven 本身的问题。
我想问题可能在于我试图在模块中执行一个 java 类并且因为 maven 没有模块化所以失败了? 也许有人可以证实或证伪这个理论?
@扩展 2:
从我的 pom 中删除 jacoco 插件后,我得到了另一个不同的错误:
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java (default) on project gentr64: Execution default of goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java Failed: Module maven.core contains package org.apache.maven.plugin,module maven.plugin.api exports package org.apache.maven.plugin to maven.core -> [Help 1]
解决方法
最后,当尝试在模块化 jar 上使用 exec:java 时,maven 3.6.3 和 exec-maven-plugin 无法正常工作。
作为解决方法/解决方案,我使用了以下内容:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.2</version>
<executions>
<execution>
<id>copy</id>
<phase>initialize</phase>
<goals>
<goal>copy</goal>
</goals>
<configuration>
<artifactItems>
<artifactItem>
<groupId>de.powerstat.fb</groupId>
<artifactId>generator</artifactId>
<version>1.0-SNAPSHOT</version>
<type>jar</type>
<overWrite>false</overWrite>
<outputDirectory>target</outputDirectory>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<executable>java</executable>
<arguments>
<argument>-jar</argument>
<argument>target/generator-1.0-SNAPSHOT.jar</argument>
<argument>${fb.hostname}</argument>
<argument>${fb.port}</argument>
<argument>${fb.username}</argument>
<argument>${fb.password}</argument>
<argument>${project.build.directory}</argument>
</arguments>
</configuration>
<executions>
<execution>
<phase>generate-sources</phase>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
</plugin>