google-app-engine - maven google app engine 项目中 datanucleus 增强器的冲突版本

Question

我在设置 datanucleus 增强器以用于谷歌应用引擎项目时遇到问题。如果我使用 datanucleus eclipse 插件一切顺利，但在我的 maven 项目中我得到一个奇怪的版本冲突错误。

我的 POM 有这些数据核引用:

<dependency>
    <groupId>org.datanucleus</groupId>
    <artifactId>datanucleus-core</artifactId>
    <version>1.1.0</version>
</dependency>

...

<plugin>
    <groupId>org.datanucleus</groupId>
    <artifactId>maven-datanucleus-plugin</artifactId>
    <version>1.1.0</version>
    <configuration>
        <mappingIncludes>**/*.class</mappingIncludes>
        <verbose>true</verbose>
        <enhancerName>ASM</enhancerName>
        <api>JDO</api>
    </configuration>
    <executions>
        <execution>
        <phase>compile</phase>
        <goals>
            <goal>enhance</goal>
        </goals>
        </execution>
    </executions>
</plugin>

当我尝试构建项目时出现以下错误:

Exception in thread "main" Plugin (Bundle) "org.datanucleus" is already registered. Ensure you dont have multiple JAR versions of the same plugin in the classpath. The URL "file:/Users/drome/.m2/repository/org/datanucleus/datanucleus-core/1.1.0/**datanucleus-core-1.1.0.jar**" is already registered, and you are trying to register an identical plugin located at URL "file:/Users/drome/.m2/repository/org/datanucleus/datanucleus-core/1.1.3/**datanucleus-core-1.1.3.jar**."org.datanucleus.exceptions.NucleusException: Plugin (Bundle) "org.datanucleus" is already registered. Ensure you dont have multiple JAR versions of the same plugin in the classpath. The URL "file:/Users/drome/.m2/repository/org/datanucleus/datanucleus-core/1.1.0/datanucleus-core-1.1.0.jar" is already registered, and you are trying to register an identical plugin located at URL "file:/Users/drome/.m2/repository/org/datanucleus/datanucleus-core/1.1.3/datanucleus-core-1.1.3.jar."at org.datanucleus.plugin.NonManagedPluginRegistry.registerBundle(NonManagedPluginRegistry.java:437)at org.datanucleus.plugin.NonManagedPluginRegistry.registerBundle(NonManagedPluginRegistry.java:343)at org.datanucleus.plugin.NonManagedPluginRegistry.registerExtensions(NonManagedPluginRegistry.java:227)at org.datanucleus.plugin.NonManagedPluginRegistry.registerExtensionPoints(NonManagedPluginRegistry.java:159)at org.datanucleus.plugin.PluginManager.registerExtensionPoints(PluginManager.java:82)at org.datanucleus.OMFContext.(OMFContext.java:164)at org.datanucleus.enhancer.DataNucleusEnhancer.(DataNucleusEnhancer.java:171)at org.datanucleus.enhancer.DataNucleusEnhancer.(DataNucleusEnhancer.java:149)at org.datanucleus.enhancer.DataNucleusEnhancer.main(DataNucleusEnhancer.java:1157)

我不明白为什么 datanucleus 需要 maven 下载 datanucleus-core-1.1.3.jar，因为它没有在 pom.xml 中引用

我也不明白为什么要注册datanucleus-core-1.1.3.jar...

有什么想法吗？提前致谢...

Answer 1

DN M2 插件会提取它完成工作所需的可用 DN jar 的最新版本(除了使用最新版本之外，没有其他明智的方法可以做到这一点)。你想限制“核心”到不同的版本，要么通过指定核心的插件依赖，要么在你的应用程序中指定它

<dependency>
    <groupId>org.datanucleus</groupId>
    <artifactId>datanucleus-core</artifactId>
    <version>1.1.0</version>
    <scope>runtime</scope> 
</dependency>