Spring Boot Kotlin 找不到存储库 Bean

Question

我刚刚开始使用 Spring Boot + Kotlin，我正在尝试 JPA 的 PagingAndSortingRepository 接口，所以我编写了以下接口：

interface CustomerRepository : PagingAndSortingRepository<Customer, Long>

Customer 的型号如下：

@Entity
data class Customer(
    @Id @GeneratedValue var id: Long,
    var name: String
)

现在我正在尝试将其与CustomerService 连接起来，如下所示：

@Service
class CustomerService(
    private val customerRepository: CustomerRepository
) {
    fun getAllCustomers(): Collection<Customer> = customerRepository.findAll().toList()
    fun addCustomer(customer: Customer) = customerRepository.save(customer)
    fun deleteCustomer(customer: Customer) = customerRepository.delete(customer)
    fun updateCustomer(customer: Customer) = customerRepository.save(customer)
}

Application 看起来像这样：

@SpringBootApplication
@Configuration
@EnableAutoConfiguration
@EnableJpaRepositories
class Application

fun main(args: Array<String>) {
    runApplication<Application>(*args)
}

我已经添加了我认为需要的依赖项，如下所示：

plugins {
    id("org.springframework.boot") version "2.5.0-SNAPSHOT"
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    kotlin("jvm") version "1.4.30"
    kotlin("plugin.spring") version "1.4.30"
}

implementation("org.springframework.boot:spring-boot-starter-web")
implementation("org.springframework.boot:spring-boot-starter-data-jpa")
implementation("org.apache.derby:derby:10.15.2.0")
implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
implementation("org.jetbrains.kotlin:kotlin-reflect")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")

Spring Boot 无法找到一种有意义的 bean，因为我还没有定义它。但是阅读文档，看起来应该是由 Spring Boot 生成的：Spring Boot Data Repositories

Application.properties 是

spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration

我得到的错误信息是：

Description:
Parameter 0 of constructor in com.ubiquifydigital.crm.service.CustomerService required a bean named 'entityManagerFactory' that could not be found.

Action:
Consider defining a bean named 'entityManagerFactory' in your configuration.

我看到了一些关于此的不同帖子，并尝试添加 Configuration、AutoConfiguration 和 EnableJpaRepositories 注释，但这只会将错误更改为 entityManagerFactory not found 而不是 CustomerRepository not found。

Answer 1

当使用默认内存数据库时，您必须定义

spring.jpa.hibernate.ddl-auto=update

在 application.properties 中通知here。您还缺少 @Autowired 注释。 entityManagerFactory 丢失是因为默认的 auo 配置已关闭，在这种情况下，应用程序希望您执行所有必要的配置，而您又没有这样做。因此，请保持默认配置并更改您需要的内容。

此代码假定在单个文件中。

如果您有多个包，那么您可能需要按照link 中的说明添加 工作代码：

package com.example.demo

import com.fasterxml.jackson.annotation.JsonProperty
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.KotlinModule
import lombok.*
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.context.annotation.Primary
import org.springframework.data.repository.CrudRepository
import org.springframework.stereotype.Repository
import org.springframework.web.bind.annotation.*
import java.util.*
import javax.persistence.Entity
import javax.persistence.GeneratedValue
import javax.persistence.Id
import javax.persistence.Table

@SpringBootApplication
open class SpringBootDerbyAppApplication

fun main(args: Array<String>) {
    runApplication<SpringBootDerbyAppApplication>(*args)
}


@Entity
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@Table(name = "applog")
internal class AppLog {
    @Id
    @GeneratedValue
    private val id: Long = 0

    @JsonProperty
    private val name: String? = null
}

@Configuration
open class ObjectMapperConfiguration {
    @Bean
    @Primary
    open fun objectMapper() = ObjectMapper().apply {
        registerModule(KotlinModule())
    }
}

@RestController
@RequestMapping(path = ["/logs"])
internal class LogController @Autowired constructor(private val appLogRepository: AppLogRepository) {
    @GetMapping(path = ["/"])
    fun logs(): MutableIterable<AppLog> {
        return appLogRepository.findAll()
    }

    @PostMapping(path = ["/"])
    fun add(@RequestBody appLog: AppLog): AppLog {
        appLogRepository.save(appLog)
        return appLog
    }

}

@Repository
internal interface AppLogRepository : CrudRepository<AppLog, Long>

gradle 文件

plugins {
    id 'org.springframework.boot' version '2.4.3'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id 'org.jetbrains.kotlin.jvm' version '1.5.0-M1'
}

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

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
    maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    compileOnly 'org.projectlombok:lombok'
    runtimeOnly 'org.apache.derby:derby'
    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    implementation("com.fasterxml.jackson.module:jackson-module-kotlin")

}

test {
    useJUnitPlatform()
}
compileKotlin {
    kotlinOptions {
        jvmTarget = "1.8"
    }
}
compileTestKotlin {
    kotlinOptions {
        jvmTarget = "1.8"
    }
}