Maven 幻象托管依赖项

Question

我刚刚遇到了一个非常奇怪的依赖问题，以前从未见过。

我有一个父项目，它在 dependencyManagement 中声明了 Netty 库的版本：

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-bom</artifactId>
    <version>4.1.29.Final</version>
    <type>pom</type>
    <scope>import</scope>
</dependency>

我有声明依赖于 Netty JAR 的子模块，例如：

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-transport</artifactId>
</dependency>

由于某种原因，保留的 Netty 版本是 4.1.27.Final 并且在任何地方都没有提及！！

我认为 Eclipse 可能会导致问题，所以我尝试在命令行上使用 mvn 可执行文件 - 同样的事情。我认为这可能与我本地 Maven 存储库中安装的 POM/JAR 有一些冲突，所以我删除了更高 com 目录中的整个目录 - 同样的事情。

我不知道这里发生了什么 - 从未见过 Maven 的这种行为。

使用 Eclipse，如果我查看父项目的有效 POM，我会在 dependencyManagement 中看到版本为 4.1.27.Final 的所有 Netty 依赖项。但我不知道它从哪里获得这些依赖项......

---

父POM（只有依赖和依赖管理）：

<dependencies>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.3</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.session</groupId>
            <artifactId>spring-session-bom</artifactId>
            <version>Apple-SR1</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>${spring.boot.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>

        <!-- Apache Commons -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.8</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-csv</artifactId>
            <version>1.5</version>
        </dependency>
        <dependency>
            <groupId>commons-cli</groupId>
            <artifactId>commons-cli</artifactId>
            <version>1.4</version>
        </dependency>

        <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-java-sdk-bom</artifactId>
            <version>1.11.401</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>

        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>${c3p0.version}</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.connector.version}</version>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-bom</artifactId>
            <version>4.1.29.Final</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>

        <dependency>
            <groupId>dnsjava</groupId>
            <artifactId>dnsjava</artifactId>
            <version>2.1.8</version>
        </dependency>

        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>26.0-jre</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>${aspectjrt.version}</version>
        </dependency>
    </dependencies>
</dependencyManagement>

子 POM：

<dependencies>
    <!-- dependency to other child modules -->

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-log4j2</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jetty</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-json</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-websocket</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-messaging</artifactId>
    </dependency>

    <dependency>
        <groupId>org.eclipse.jetty.websocket</groupId>
        <artifactId>websocket-client</artifactId>
    </dependency>

    <dependency>
        <groupId>io.netty</groupId>
        <artifactId>netty-transport</artifactId>
    </dependency>

    <dependency>
        <groupId>commons-cli</groupId>
        <artifactId>commons-cli</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
    </dependency>

    <dependency>
        <groupId>dnsjava</groupId>
        <artifactId>dnsjava</artifactId>
    </dependency>

    <dependency>
        <groupId>com.github.kenglxn.qrgen</groupId>
        <artifactId>javase</artifactId>
        <version>2.4.0</version>
    </dependency>

    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
        <groupId>com.mchange</groupId>
        <artifactId>c3p0</artifactId>
    </dependency>

    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
    </dependency>
</dependencies>

Answer 1

它来自spring-boot-dependencies，它也声明了netty-bom。 也许改变顺序会有所帮助。你也可以排除它。