如何在spring boot中将所有常见依赖项从maven模块移动到父模块

Question

我有两个简单的Spring Boot 应用程序，一个是eureka-server，另一个是eureka-client。它们都驻留在 maven 聚合器模块 eureka-sample 中。

我在eureka-server 和eureka-client 应用程序中都有一些共同的依赖项，我想将它们移至父pom，这样我就不必时不时地将它们包含在每个子模块中。

我尝试将依赖项 spring-boot-starter-test 从子模块移动到 <dependencyManagement> 部分下的父 pom 中，但随后子模块中的测试无法编译，因为这些类无法找到 jar。可能是我配置错误或放置在错误的部分。

我怎样才能做到这一点？

eureka-sample（父 pom.xml）

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.study.spring</groupId>
    <artifactId>eureka-sample</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>
    <name>eureka-sample</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR4</spring-cloud.version>
    </properties>

    <modules>
        <module>eureka-server</module>
        <module>eureka-client</module>
    </modules>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.8.RELEASE</version>
        <relativePath />
    </parent>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

eureka-server/pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>eureka-server</artifactId>
    <packaging>jar</packaging>
    <name>eureka-server</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>com.study.spring</groupId>
        <artifactId>eureka-sample</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>

        **<!-- ALL THE FOLLOWING 3 DEPENDENCIES SHOULD GO TO PARENT POM SO THAT I DO NOT HAVE TO PUT THEM IN EVERY CHILD MODULE -->**
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

eureka-client/pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <artifactId>eureka-client</artifactId>
    <packaging>jar</packaging>
    <name>eureka-client</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>com.study.spring</groupId>
        <artifactId>eureka-sample</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>

        **<!-- ALL THE FOLLOWING 3 DEPENDENCIES SHOULD GO TO PARENT POM SO THAT I DO NOT HAVE TO PUT THEM IN EVERY CHILD MODULE -->**
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

Answer 1

尝试将公共依赖项放在父 .pom 的 <dependencies> 部分而不是 <dependencyManagement> 部分中。

使用<dependencyManagement>，您只需准备和配置所有子模块的依赖项，但为了实际使用它们，您仍然需要从子模块中引用它们。

区别很微妙，但很重要 - 详情请参阅 https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html。