java - 无法将带有 Gradle 的单体 Spring Boot 应用程序转换为多模块

Question

实际上，我有一个带有 gradle 的整体 Spring Boot 应用程序，我想将其转换为多模块。它只是一个简单的应用程序来做CRUD书。

我的应用程序结构如下，

simple-app
| src/main/java/example/simpleapp
| -------------------------------/controller`
| -------------------------------/exception
| -------------------------------/model
| -------------------------------/repository
| -------------------------------/service
| -------------------------------SimpleAppAplication
| build.gradle
| settings.gradle

我一步一步地将所有包分离成模块，然后我的文件夹结构更改为如下所示

simple-app
| controller
| | src
| | build.gradle
| exception
| | src
| | build.gradle
| main-app
| | src
| | build.gradle
| model
| | src
| | build.gradle
| repository
| | src
| | build.gradle
| service
| | src
| | build.gradle
| build.gradle
| settings.gradle

如果我运行该项目，它工作得很好并返回应该返回的结果。

但是，当我构建项目时，它会变成这样的错误。

PC:~/simple-app$ ./gradlew build
> Task :repository:compileJava FAILED
/simple-appp/repository/src/main/java/example/simpleapp/repository/BookRepository.java:3: error: package nanihutagaol.simpleapp.model does not exist
import example.simpleapp.model.Book;
                               ^
simple-app/repository/src/main/java/example/simpleapp/repository/BookRepository.java:9: error: cannot find symbol
public interface BookRepository extends JpaRepository<Book, Long> {
                                                  ^
symbol: class Book
2 errors
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':repository:compileJava'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.4.1/userguide/command_line_interface.html#sec:command_line_warnings
BUILD FAILED in 2s
3 actionable tasks: 1 executed, 2 up-to-date

我不明白为什么会出现这样的错误，因为模型包是存在的。希望你们中的一位能够给出解决方案。

先谢谢了...

编辑:

在存储库/build.gradle

group = 'example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
  mavenCentral()
}
dependencies {
  implementation project(":model")
  implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
  implementation 'org.springframework.boot:spring-boot-starter-web'
}

在模型/build.gradle

group = 'example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
  mavenCentral()
}
configurations {
  compileOnly {
    extendsFrom annotationProcessor
  }
}
dependencies {
  implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
  implementation 'org.springframework.boot:spring-boot-starter-web'
  compileOnly 'org.projectlombok:lombok'
  annotationProcessor 'org.projectlombok:lombok'
  runtimeOnly 'org.postgresql:postgresql'
}

Answer 1

在尝试理解其他类似主题后，我终于可以解决该错误。

所以我在 root/build.gradle 上的第一个语法如下

plugins {
    id 'org.springframework.boot' version '2.3.0.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
}
group = 'example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
    mavenCentral()
}

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

dependencies {
    implementation project(":main-app")
}

test {
    useJUnitPlatform()
}

subprojects {
    apply plugin: 'org.springframework.boot'
    apply plugin: 'io.spring.dependency-management'
    apply plugin: 'java'
}

然后我通过在 root/build.gradle 和 subprojects/build.gradle

上添加以下代码来更新它

bootJar {
  enabled = false
}

jar {
  enabled = true
}

基于 https://spring.io/guides/gs/multi-module/ 上的指南，该代码用于告诉 Gradle 不要为 Library 项目构建可执行 jar。

我不知道为什么我之前错过了这一步。所以，我的最后一个 root/build.gradle 看起来像

plugins {
    id 'org.springframework.boot' version '2.3.0.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
}

group = 'example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

bootJar {
    enabled = false
}

jar {
    enabled = true
}

repositories {
    mavenCentral()
}

dependencies {
    implementation project(":main-app")
}

test {
    useJUnitPlatform()
}

subprojects {
    apply plugin: 'org.springframework.boot'
    apply plugin: 'io.spring.dependency-management'
    apply plugin: 'java'

    group = 'example'
    version = '0.0.1-SNAPSHOT'
    sourceCompatibility = '1.8'

    repositories {
        mavenCentral()
    }
    
    bootJar {
        enabled = false
    }

    jar {
        enabled = true
    }
}

然后，我只需添加依赖项标签即可更新所有 subproject/build.gradle。例如repository/build.gradle

dependencies {
    implementation project(":model")
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-web'
}

这就是我所有的问题解释......:)