spring-boot-starter-jetty和Jetty模块-Maven Magic

Question

We're using spring-boot-starter-jetty in our maven pom, which means we don't have any direct dependency on jetty hence no control on its version.

This all works good, but we now need to add a dependency onone of jetty's modules, which are using the same jetty version convention.

This is all great and dandy, but because we can't use spring-boot-starter-jetty as our root pom, we're declaring jetty's version again under the module's dependency declaration, something like this:

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-jetty</artifactId>
   <version>1.4.3-RELEASE</version>
</dependency>
<dependency>
   <groupId>org.eclipse.jetty</groupId>
   <artifactId>jetty-nosql</artifactId>
   <version>9.3.14.v20161028</version>
</dependency>

This is no fun PLUS dangerous as if we upgrade one of them, we have to remember to upgrade the latter to the same version.

I know we can add an exclude under the module's dependency but this feels like a hack plus still doesn't fully protect us from breaking changes.

Is there anyway to extract the jetty version from spring boot and reuse it for the module's dependency?

Thanks!!

Answer 1

Maven creates the version properties for it's dependencies in the effective POM . For jetty it's jetty.version

So your dependencies will become

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jetty</artifactId>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-nosql</artifactId>
        <version>${jetty.version}</version>
    </dependency>

Here's complete POM

<?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>TestDependency</groupId>
    <artifactId>TestDependency</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>TestDependency</name>
    <description>TestDependency</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.3.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-nosql</artifactId>
            <version>${jetty.version}</version>
        </dependency>
    </dependencies>

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


</project>

It's worth pointing out that this is not required with the latest version of Spring Boot . I checked with the 1.5.4.RELEASE . Following is suficient.

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jetty</artifactId>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-nosql</artifactId>
    </dependency>

Complete POM

<?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>TestDependency</groupId>
    <artifactId>TestDependency</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>TestDependency</name>
    <description>TestDependency</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-nosql</artifactId>
        </dependency>
    </dependencies>

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


</project>

Effective POM can be generated by using following command

mvn help:effective-pom

Or if you're using Spring Tool Suite or latest version of Eclipse then you can directly check it inside the bottom tab in the Maven POM Editor

Edit

Without spring-boot parent pom the same can be done using dependencyManagement

Following is the complete pom without spring-boot parent

<?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>TestDependency</groupId>
    <artifactId>TestDependency</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>TestDependency</name>
    <description>TestDependency</description>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>1.4.3.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-nosql</artifactId>
            <version>${jetty.version}</version>
        </dependency>
    </dependencies>

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


</project>