Maven `pre` 和 `post` 阶段

Question

是 pre和 post执行相关阶段时总是执行阶段？例如，如果我这样做 mvn clean , 这会执行 mvn post-clean相也？

我在看 https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html#Lifecycle_Reference ，其中说:

The following lists all build phases of the default, clean and site lifecycles, which are executed in the order given up to the point of the one specified.

所以严格来说，自从 post-clean在 clean 之后, 如果我只是执行 mvn clean 就不应该执行.但我的直觉是不同的——虽然，我没有找到一种方法来验证这一点，因为 maven stdout 不会打印它正在执行的阶段。

任何人都可以权衡答案以及您如何验证吗？

Answer 1

您可以将插件(例如 echo-maven-plugin )绑定(bind)到 clean 的阶段。生命周期，以帮助验证是否/何时执行每个阶段。

例如，给定以下插件定义:

<plugin>
    <groupId>com.github.ekryd.echo-maven-plugin</groupId>
    <artifactId>echo-maven-plugin</artifactId>
    <version>1.2.0</version>
    <executions>
        <execution>
            <id>pre-clean</id>
            <phase>pre-clean</phase>
            <goals>
                <goal>echo</goal>
            </goals>
            <configuration>
                <message>In 'pre-clean'</message>
            </configuration>
        </execution>
        <execution>
            <id>clean</id>
            <phase>clean</phase>
            <goals>
                <goal>echo</goal>
            </goals>
            <configuration>
                <message>In 'clean'</message>
            </configuration>
        </execution>
        <execution>
            <id>post-clean</id>
            <phase>post-clean</phase>
            <goals>
                <goal>echo</goal>
            </goals>
            <configuration>
                <message>In 'post-clean'</message>
            </configuration>
        </execution>
    </executions>
</plugin>

调用 mvn clean将产生以下输出:

$ mvn clean
[INFO] Scanning for projects...
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (pre-clean) @ sandbox ---
[INFO] In 'pre-clean'
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ sandbox ---
[INFO] Deleting target
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (clean) @ sandbox ---
[INFO] In 'clean'

所以，没有调用 post-clean相那里。

调用 mvn clean compile将产生以下输出:

$ mvn clean compile
[INFO] Scanning for projects...
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (pre-clean) @ sandbox ---
[INFO] In 'pre-clean'
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ sandbox ---
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (clean) @ sandbox ---
[INFO] In 'clean'
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ sandbox ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.5.1:compile (default-compile) @ sandbox ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 5 source files to ...

同样，没有调用 post-clean相那里。这意味着 maven-clean-plugin(也许没有别的)没有绑定(bind)到 post-clean .

调用 mvn post-clean将导致 post-clean阶段被调用...

$ mvn post-clean
[INFO] Scanning for projects...
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (pre-clean) @ sandbox ---
[INFO] In 'pre-clean'
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ sandbox ---
[INFO] Deleting target
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (clean) @ sandbox ---
[INFO] In 'clean'
[INFO] 
[INFO] --- echo-maven-plugin:1.2.0:echo (post-clean) @ sandbox ---
[INFO] In 'post-clean'

因此，基于上述测试，我认为以下陈述是正确的:

post-clean是 不是 当您调用 clean 时调用

post-clean是 仅限 当你显式调用 post-clean 时调用(注意:直接调用 pre- 和 post- 阶段是不寻常的)