maven - 为什么maven会下载很多相同依赖的版本？

Question

我正在 maven 3 上运行构建，它尝试下载同一 JAR 的许多不同版本。我没有指定该 JAR 作为依赖项。知道为什么要这样做吗？

Downloading: http://download.java.net/maven/2/org/codehaus/jackson/jackson-core-asl/maven-metadata.xml
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[WARNING] The POM for org.codehaus.jackson:jackson-core-asl:jar:1.7.0-SNAPSHOT-20101126.221009-1 is missing, no dependency information available
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Answer 1

您会注意到它实际上并没有下载 jar，只是下载 POM。我猜测是指定的版本不是固定版本，并且 maven 正在挖掘可用版本以找出应该使用哪个版本。

该组件包含在依赖树中的某个位置。您可以使用 mvn dependency:tree 来找出位置。当然，即使为了显示树，它仍然需要下载所有 POM，但您现在已经获得了它们:)