如何让maven警告转换依赖版本不匹配？

Question

在下面的示例Maven依赖项中,slf4j依赖项想要引入log4j 1.2.17并且log4j显式依赖项想要引入1.2.15.Maven将log4j解析为版本1.2.15但是,没有警告Maven打印出sl4j想要更高版本的log4j.

我怎样才能让Maven警告这些类型的冲突,而不是默默地采用1.2.15版本？

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-log4j12</artifactId>
  <version>1.7.2</version>
</dependency>
<dependency>
  <groupId>log4j</groupId>
  <artifactId>log4j</artifactId>
  <version>1.2.15</version>
</dependency>

Answer 1

简而言之,应该使用Maven-enforcer-plugin来处理这个问题.

您只需要配置强制执行器插件

<project>
  ...
  <build>
    <plugins>
      ...
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-enforcer-plugin</artifactId>
        <version>1.1.1</version>
        <executions>
          <execution>
            <id>enforce</id>
            <configuration>
              <rules>
                <DependencyConvergence/>
              </rules>
            </configuration>
            <goals>
              <goal>enforce</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      ...
    </plugins>
  </build>
  ...
</project>

更详细地说,正如文档页面中所说,这样的事情具有转换依赖性不匹配:

<dependencies>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-jdk14</artifactId>
    <version>1.6.1</version>
  </dependency>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-nop</artifactId>
    <version>1.6.0</version>
  </dependency>
</dependencies>  

如果没有强制规则,它将默默地"工作",但是在规则设置的情况下,它将使构建失败

Dependency convergence error for org.slf4j:slf4j-api1.6.1 paths to dependency are:

[ERROR]
Dependency convergence error for org.slf4j:slf4j-api:1.6.1 paths to dependency are:
+-org.myorg:my-project:1.0.0-SNAPSHOT
  +-org.slf4j:slf4j-jdk14:1.6.1
    +-org.slf4j:slf4j-api:1.6.1
and
+-org.myorg:my-project:1.0.0-SNAPSHOT
  +-org.slf4j:slf4j-nop:1.6.0
    +-org.slf4j:slf4j-api:1.6.0

因此,当用户收到有关失败构建的错误消息时,她可以通过排除来修复它,例如

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-jdk14</artifactId>
  <version>1.6.1</version>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-nop</artifactId>
  <version>1.6.0</version>
  <exclusions>
    <exclusion>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
    </exclusion>
  </exclusions>
</dependency>