Gradle － (4) Spring Boot Multiple Project

Root (Parent)

plugins

plugins {
    java
    id("org.springframework.boot") version "2.6.2" apply false
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    kotlin("jvm") version "1.6.10"
    kotlin("plugin.spring") version "1.6.10"
}

重點在於org.springframework.boot不要每個sub projects都使用，因為會有做為共用library的jar，
所以通常不需要每一個Project都build 成spring boot可執行的jar。

all Projects

用allprojects來控制建構中所有專案的設定（包含root）。

allprojects {
    group = "tw.elliot"
    version = "1.0"

    repositories {
        mavenCentral()
    }
}

tasks.jar {
    enabled = false
}

repositories

repositories {
    mavenCentral()
}

等於Maven中對於repositories的設定

<repositories>
    <repository>
        <id>central</id>
        <name>Maven Central</name>
        <layout>default</layout>
        <url>https://repo1.maven.org/maven2/</url>
    </repository>
</repositories>

disable task jar

tasks.jar {
    enabled = false
}

由於root(Parent) 並不需要進行任何建構，所以將build jar這task取消。

subprojects

subprojects用來設定所有sub projects，主要包含dependencyManagement、unitTest

subprojects {

    apply(plugin = "java")
    apply(plugin = "io.spring.dependency-management")
    apply(plugin = "kotlin")
    apply(plugin = "jacoco")

    dependencyManagement {
        imports {
            mavenBom(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
        }

        dependencies {
            dependency("com.google.guava:guava:30.0-jre")
        }
    }

    dependencies {
        implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
        ....
    }

    ....

}

dependencyManagement

import maven bom 可以同於下列於maven中的設定

<dependencyManagement>
    <dependencies>
        <!--BOM-->
        <dependency>
            <!-- Import dependency management from Spring Boot -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>${spring.boot.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

也可用dependencies:dependency 來設定單一的library版本
效果同於maven中在dependencyManagement的設定

<dependencyManagement>
    <dependencies>
        <!--BOM-->
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>${guava.version}</version>
        </dependency>
    </dependencies>
</dependencyManagement>

core

做為共用library的模組，通常僅需加入要使用的dependencies

dependencies {
    implementation("com.google.guava:guava")
}

frontend and backend

做為spring boot 的主要模組，必需加入spring boot主要的gradle plugin

plugins {
    id("org.springframework.boot")
}

dependencies 中則需加入共用的模組與spring boot 相關的library

dependencies {
    implementation(project(":core"))
    implementation("org.springframework.boot:spring-boot-starter-actuator")
    implementation("org.springframework.boot:spring-boot-starter-web")
}

參考

Github Source Code