java - 影子插件 Gradle : What does mergeServiceFiles() do?

Question

在我的 build.gradle 文件中，我需要添加以下行:

shadowJar {
    mergeServiceFiles()
}

否则 jar 无法正常运行。我想知道这条线到底是做什么的？我在 Eclipse Luna 中使用 Gradle 插件。我在一个依赖于另一个 Java 项目的 Java 项目上创建了 jar。

Answer 1

mergeServiceFiles 声明为 here其实现如下:

/**
 * Syntactic sugar for merging service files in JARs
 * @return
 */
public ShadowJar mergeServiceFiles() {
    try {
        transform(ServiceFileTransformer.class);
    } catch (IllegalAccessException e) {
    } catch (InstantiationException e) {
    }
    return this;
}

如您所见，它使用定义为 here 的 ServiceFileTransfomer .从它的文档:

Modified from org.apache.maven.plugins.shade.resource.ServiceResourceTransformer.java

Resources transformer that appends entries in META-INF/services resources into a single resource. For example, if there are several META-INF/services/org.apache.maven.project.ProjectBuilder resources spread across many JARs the individual entries will all be concatenated into a single META-INF/services/org.apache.maven.project.ProjectBuilder resource packaged into the resultant JAR produced by the shading process.