maven 依赖相关

maven pom 依赖

有些找到的maven依赖写的type是pom类型, 一时不知如何处理.

<!-- https://mvnrepository.com/artifact/org.apache.flink/flink-walkthroughs -->
<dependency>
    <groupId>org.apache.flink</groupId>
    <artifactId>flink-walkthroughs</artifactId>
    <version>1.17.0</version>
    <type>pom</type>
</dependency>

搜索了一番, 有两个用法.

放置在<dependencyManagement>里面, 并且额外添加<scope>import </scope>, 可以使得这个pom依赖里的<dependencyManagement>也被引用进来, 但是具体<dependencies>里的依赖就不会被引用了. 后面需要使用, 还是需要参考<dependencyManagement>的用法, 额外写<dependency>, 只是不用写版本号.
只是放置在<dependencies>中作为简单依赖使用, 那就得看pom文件里写了哪些依赖项, 只有这些项目会被引用.

所以两种用法, 其实都需要具体查看下pom文件里的内容, 看看到底要怎么使用, 引用<dependencyManagement>或是<dependencies>.

比如上面flink的依赖, pom的文档在maven仓库里可以看到https://repo1.maven.org/maven2/org/apache/flink/flink-walkthroughs/1.17.0/flink-walkthroughs-1.17.0.pom. 里面并没有dependencyManagement的内容, 只有普通的dependencies依赖, 还不如直接去引用里面具体的子模块https://repo1.maven.org/maven2/org/apache/flink/flink-walkthrough-common/1.17.0/flink-walkthrough-common-1.17.0.pom

<!-- https://mvnrepository.com/artifact/org.apache.flink/flink-walkthrough-common -->
<dependency>
    <groupId>org.apache.flink</groupId>
    <artifactId>flink-walkthrough-common</artifactId>
    <version>1.17.0</version>
</dependency>

What is the difference between "pom" type dependency with scope "import" and without "import"

关键是这句话: So basically the two different mechanisms are used for importing/including the two different types of dependencies (managed dependencies and normal dependencies).

https://stackoverflow.com/questions/11778276/what-is-the-difference-between-pom-type-dependency-with-scope-import-and-wit

You can only import managed dependencies. This means you can only import other POMs into the dependencyManagement section of your project's POM. i.e.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>other.pom.group.id</groupId>
            <artifactId>other-pom-artifact-id</artifactId>
            <version>SNAPSHOT</version>
            <scope>import</scope>
            <type>pom</type>
        </dependency>   
    </dependencies>
</dependencyManagement>

What then happens is that all the dependencies defined in the dependencyManagement section of the other-pom-artifact-id are included in your POM's dependencyManagement section. You can then reference these dependencies in the dependency section of your POM (and all of its child POMs) without having to include a version etc.

However if in your POM you simply define a normal dependency to other-pom-artifact-id then all dependencies from the dependency section of the other-pom-artifact-id are included transitively in your project - however the dependencies defined in the dependencyManagement section of the other-pom-artifact-id are not included at all.

So basically the two different mechanisms are used for importing/including the two different types of dependencies (managed dependencies and normal dependencies).

maven 依赖相关

maven pom 依赖​

maven pom 依赖