Maven 依赖解析(冲突) [英] Maven dependency resolution (conflicted)

问题描述

假设我有四个项目:

• 项目 A(依赖于 B 和 D)
• 项目 B(依赖于 D)
• 项目 C(依赖于 D)
• 项目 D

在这种情况下，如果我运行项目 A，Maven 将正确解析对 D 的依赖关系.如果我理解正确，Maven 总是采用最短路径的依赖关系.由于 D 是 A 的直接依赖项，因此将使用它而不是在 B 中指定的 D.

In this scenario if I run project A, Maven will correctly resolve the dependency to D. If I understand this correctly Maven always takes the dependency with the shortest path. Since D is a direct dependency of A it will be used rather then, the D which is specified within B.

但现在假设这个结构:

• 项目 A(依赖于 B 和 C)
• 项目 B(依赖于 D)
• 项目 C(依赖于 D)
• 项目 D

在这种情况下，解析 D 的路径具有相同的深度.发生的情况是Maven会发生冲突.我知道可以告诉 Maven 他应该排除依赖项.但我的问题是如何解决此类问题.我的意思是在现实世界的应用程序中，您有很多依赖项，也可能有很多冲突.

In this case the paths to resolving D have the same depth. What happens is that Maven will have a conflict. I know that it is possible to tell Maven that he should exclude dependencies. But my question is how to address such kind of problems. I mean in a real world application you have a lot of dependencies and possibly a lot of conflicts as well.

最佳实践解决方案是否真的要排除某些内容，或者是否有其他可能的解决方案?当我突然收到 ClassNotFound Exception 时，我发现很难处理，因为某些版本已经更改，这导致 Maven 采取不同的依赖项.当然，知道这个事实会让我们更容易猜测问题是依赖冲突.

Is the best practice solution really to exclude stuff or are there other possible solutions to this? I find it very hard to deal with when i suddenly get a ClassNotFound Exception because some versions have changed, which caused Maven to take a different dependency. Of course, knowing this fact makes it a little bit easier to guess that the problem is a dependency conflict.

我使用的是 maven 2.1-SNAPSHOT.

I'm using maven 2.1-SNAPSHOT.

推荐答案

解决此类情况的 Maven 方法是在项目的根 pom 中包含一个 部分，您可以在其中指定将使用哪个库的哪个版本.

The maven way of resolving situations like this is to include a <dependencyManagement> section in your project's root pom, where you specify which version of which library will be used.

<dependencyManagement>
  <dependencies>
    <dependency>
        <groupId>foo</groupId>
        <artifactId>bar</artifactId>
        <version>1.2.3</version>
    </dependency>
   </dependencies>
</dependencyManagement>

现在无论依赖项请求哪个版本的库 foo:bar，1.2.3 版本将始终用于此项目和所有子项目.

Now no matter which version of library foo:bar is requested by a dependency, version 1.2.3 will always be used for this project and all sub-projects.

参考:

• 依赖管理

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