java - Maven 依赖声明分类器属性的目的是什么？

Question

我有一个 pom.xml 文件，其中我看到它们是为相同 <artifactId> 引用的 3 个依赖项区别在于标签

<classifier>sources</classifier>
<classifier>javadoc</classifier>

我已删除具有 SOURCES/JAVADOC 的依赖项并且只保留一个依赖项。我测试了我的应用程序，一切正常。

使用这个分类标签的目的是什么？以及为什么我需要重复依赖两次以添加 <classifier>带有 SOURCES/JAVADOC 的标签.

<dependency>
   <groupId>oauth.signpost</groupId>
   <artifactId>signpost-commonshttp4</artifactId>
   <version>1.2.1.2</version>
   <type>jar</type>
   <scope>compile</scope>
</dependency>
  <dependency>
   <groupId>oauth.signpost</groupId>
   <artifactId>signpost-commonshttp4</artifactId>
   <version>1.2.1.2</version>
   <type>jar</type>
      ***<classifier>javadoc</classifier>***
   <scope>compile</scope>
</dependency>
<dependency>
   <groupId>oauth.signpost</groupId>
   <artifactId>signpost-commonshttp4</artifactId>
   <version>1.2.1.2</version>
   <type>jar</type>
   ***<classifier>sources</classifier>***
   <scope>compile</scope>
</dependency> 

Answer 1

The classifier distinguishes artifacts that were built from the same POM but differ in content. It is some optional and arbitrary string that - if present - is appended to the artifact name just after the version number.

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