在Maven2的命令行中设置插件的版本

Question

我生成默认的快速入门Maven示例，并输入mvn checkstyle:checkstyle，它总是尝试使用最新的SNAPSHOT版本。也许在我的Nexus服务器上是错误的，但是我如何在Maven2的命令行上设置插件的版本，比如用2.5代替2.6-SNAPSHOT来设置checkstyle

C:\HelloWorld>mvn checkstyle:checkstyle
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'checkstyle'.
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Error building POM (may not be this project's POM).

Project ID: org.apache.maven.plugins:maven-checkstyle-plugin

Reason: Error getting POM for 'org.apache.maven.plugins:maven-checkstyle-plugin' from  the repository: Failed to resolve artifact, possibly due to a repository list that is not appropriately equipped for this artifact's metadata.
  org.apache.maven.plugins:maven-checkstyle-plugin:pom:2.6-SNAPSHOT

from the specified remote repositories:
  nexus (http://localhost:9081/nexus/content/groups/public)

for project org.apache.maven.plugins:maven-checkstyle-plugin

我猜它可能是mvn checkstyle:2.5:checkstyle，但不幸的是它不是。

当然，如果我在pom.xml中设置了构建依赖，它将会工作，但我想看看命令行是如何工作的。

Answer 1

如果您不想运行安装在本地存储库中的插件的最新版本，则需要设置版本号。为此，您需要以以下形式指定一个完全限定的目标：

mvn groupID:artifactID:version:goal

所以在你的例子中：

mvn org.apache.maven.plugins:maven-checkstyle-plugin:2.5:checkstyle

Answer 2

我使用较新版本的maven(3.3.9)的体验略有不同。如果我不是在脱机模式下运行maven，那么无论我在本地存储库中有什么，它都将总是转到远程repo。如果它找到一个较新的版本(基于maven-metadata.xml)，它将下载并使用该版本。更重要的是，它将同时扫描多个repo：

[INFO] ------------------------------------------------------------------------
[DEBUG] Resolving plugin version for com.phoenixnap.oss:springmvc-raml-plugin
[DEBUG] Could not find metadata com.phoenixnap.oss:springmvc-raml-plugin/maven-metadata.xml in local (/home/yuranos/.m2/repository)
[DEBUG] Using transporter WagonTransporter with priority -1.0 for https://repo.spring.io/libs-milestone
[DEBUG] Using transporter WagonTransporter with priority -1.0 for https://repo.spring.io/milestone
[DEBUG] Using transporter WagonTransporter with priority -1.0 for https://repo.maven.apache.org/maven2
[DEBUG] Using transporter WagonTransporter with priority -1.0 for https://repo.spring.io/snapshot
[DEBUG] Using connector BasicRepositoryConnector with priority 0.0 for https://repo.spring.io/libs-milestone
[DEBUG] Using connector BasicRepositoryConnector with priority 0.0 for https://repo.spring.io/milestone
[DEBUG] Using connector BasicRepositoryConnector with priority 0.0 for https://repo.maven.apache.org/maven2
[DEBUG] Using connector BasicRepositoryConnector with priority 0.0 for https://repo.spring.io/snapshot
Downloading: https://repo.spring.io/libs-milestone/com/phoenixnap/oss/springmvc-raml-plugin/maven-metadata.xml
Downloading: https://repo.spring.io/snapshot/com/phoenixnap/oss/springmvc-raml-plugin/maven-metadata.xml
Downloading: https://repo.maven.apache.org/maven2/com/phoenixnap/oss/springmvc-raml-plugin/maven-metadata.xml
Downloading: https://repo.spring.io/milestone/com/phoenixnap/oss/springmvc-raml-plugin/maven-metadata.xml
[DEBUG] Writing tracking file /home/yuranos/.m2/repository/com/phoenixnap/oss/springmvc-raml-plugin/resolver-status.properties
[DEBUG] Writing tracking file /home/yuranos/.m2/repository/com/phoenixnap/oss/springmvc-raml-plugin/resolver-status.properties
Downloaded: https://repo.maven.apache.org/maven2/com/phoenixnap/oss/springmvc-raml-plugin/maven-metadata.xml (2 KB at 1.0 KB/sec)
[DEBUG] Writing tracking file /home/yuranos/.m2/repository/com/phoenixnap/oss/springmvc-raml-plugin/resolver-status.properties
Downloaded: https://repo.spring.io/libs-milestone/com/phoenixnap/oss/springmvc-raml-plugin/maven-metadata.xml (2 KB at 0.9 KB/sec)
[DEBUG] Writing tracking file /home/yuranos/.m2/repository/com/phoenixnap/oss/springmvc-raml-plugin/resolver-status.properties
[DEBUG] Could not find metadata com.phoenixnap.oss:springmvc-raml-plugin/maven-metadata.xml in spring-snapshots (https://repo.spring.io/snapshot)
[DEBUG] Could not find metadata com.phoenixnap.oss:springmvc-raml-plugin/maven-metadata.xml in spring-milestones-libs (https://repo.spring.io/milestone)

更重要的是，maven似乎知道如何比较几个元数据文件并选择工件的最新版本。根据我在resolver-status.properties中看到的，Maven使用以太来解决依赖关系：

    #NOTE: This is an Aether internal implementation file, its format can be changed without prior notice.
#Mon Feb 19 23:41:24 EET 2018
maven-metadata-spring-milestones.xml.lastUpdated=1519076484366
maven-metadata-spring-snapshots.xml.error=
maven-metadata-central.xml.lastUpdated=1519076484205
maven-metadata-spring-snapshots.xml.lastUpdated=1519076484107
maven-metadata-spring-milestones-libs.xml.lastUpdated=1519076484105
maven-metadata-spring-milestones-libs.xml.error=

Answer 3

mvn org.apache.maven.plugins:maven-site-plugin:3.7.1:site