Kotlin SpringBoot and JPA - How to create relations OneToOne? - spring-boot

Question

I am trying to create a relation OneToOne between two entities and always get the error (or very similar, Error creating bean with name 'entityManagerFactory' always):
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Unknown mappedBy in: com.moises.kotlinstoreapi.model.Image.product, referenced property unknown: com.moises.kotlinstoreapi.model.Product.images
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1803) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
...
[spring-boot-devtools-2.2.1.RELEASE.jar:2.2.1.RELEASE]
Caused by: org.hibernate.AnnotationException: Unknown mappedBy in: com.moises.kotlinstoreapi.model.Image.product, referenced property unknown: com.moises.kotlinstoreapi.model.Product.images
at org.hibernate.cfg.OneToOneSecondPass.doSecondPass(OneToOneSecondPass.java:169) ~[hibernate-core-5.4.8.Final.jar:5.4.8.Final]
I can create without problems the tables if I don't put the relations.
My code:
package com.moises.kotlinstoreapi.model
import com.fasterxml.jackson.annotation.JsonManagedReference
import javax.persistence.*
import javax.validation.constraints.NotBlank
#Entity
#Table(name="images")
data class Image (
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
val id: Long = 0,
val alt: String = "",
#NotBlank
val src: String = "",
val tite: String = "",
/**
* Relations
*
*/
//#OneToOne(mappedBy="images")
#OneToOne(mappedBy = "images", cascade = [(CascadeType.ALL)], fetch= FetchType.EAGER)
#JsonManagedReference
val product: Product = Product()
)
package com.moises.kotlinstoreapi.model
import com.fasterxml.jackson.annotation.JsonManagedReference
import java.time.LocalDateTime
import javax.persistence.*
import javax.validation.constraints.NotBlank
import javax.validation.constraints.NotEmpty
import javax.validation.constraints.NotNull
#Entity
#Table(name="products")
data class Product (
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
val id: Long = 0,
#NotBlank
val title: String = "",
#NotBlank
val description: String = "",
#NotEmpty
var price: Double = 999.99,
#NotNull
var created_at: LocalDateTime = LocalDateTime.now(),
var update_at: LocalDateTime? = null,
/**
* Relations
*
*/
//#OneToOne(mappedBy="products", cascade = arrayOf(CascadeType.ALL))
//#JoinColumn(name = "id")
#OneToOne(cascade = [(CascadeType.ALL)], fetch= FetchType.EAGER)
#JoinColumn(name = "image_id")
#JsonManagedReference
val image: Image? = null
//#OneToOne(mappedBy="products", orphanRemoval=true, cascade=arrayOf(CascadeType.PERSIST))
//private val image: Image?
//#OneToOne(cascade = arrayOf(CascadeType.ALL))
//#JoinColumn(name = "purchase_line_id")
//val purchaseLine: PurchaseLine ?= null
)
I am usin IntelliJ with Maven and OpenJDK 11 in Ubuntu.
My pow.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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.moises</groupId>
<artifactId>kotlin-store-api</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>kotlin-store-api</name>
<description>API store with Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<kotlin.version>1.3.50</kotlin.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-kotlin</artifactId>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-reflect</artifactId>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jdk8</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
<testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-plugin</artifactId>
<configuration>
<args>
<arg>-Xjsr305=strict</arg>
</args>
<compilerPlugins>
<plugin>spring</plugin>
<plugin>jpa</plugin>
</compilerPlugins>
</configuration>
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-allopen</artifactId>
<version>${kotlin.version}</version>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-noarg</artifactId>
<version>${kotlin.version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>

Answer 1

you had wrong mappedBy value in Image - mappedBy = "images" it should be "image":
#OneToOne(mappedBy = "image", cascade = [(CascadeType.ALL)], fetch= FetchType.EAGER)
#JsonManagedReference
val product: Product = Product()
because Product has field image:
#JsonManagedReference
val image: Image? = null