Question

我试图在两个实体之间创建一个OneToMany关系，并且在创建名称为'entityManagerFactory'的bean时总是出错：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-11-23 12:17:20.082 ERROR 17130 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

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 javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.loader.MultipleBagFetchException: cannot simultaneously fetch multiple bags: [com.moises.kotlinstoreapi.model.Customer.purchases, com.moises.kotlinstoreapi.model.Purchase.purchasesLines]
...

我已经与其他两个实体（带购买的客户）创建了相同类型的关系，但是在这种情况下，它不会运行...

产品代码：包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 = "",
    @NotEmpty
    val price: Double = 999.99,
    @NotNull
    val created_at: LocalDateTime = LocalDateTime.now(),
    val update_at: LocalDateTime? = null,

    /**
    * Relations
    *
    */
    @OneToOne(mappedBy="product")
    val purchaseLine: PurchaseLine? = null
)

购买代码：

package com.moises.kotlinstoreapi.model

import com.fasterxml.jackson.annotation.JsonBackReference
import com.fasterxml.jackson.annotation.JsonManagedReference
import com.sun.istack.NotNull
import java.time.LocalDateTime
import javax.persistence.*
import javax.validation.constraints.NotEmpty

@Entity
@Table(name="purchases")
data class Purchase(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private val id: Long=0,
    @Column(name="notes", columnDefinition="TEXT")
    val notes: String = "",
    @NotNull
    val created_at: LocalDateTime = LocalDateTime.now(),
    val update_at: LocalDateTime? = null,

    /**
    * Relations
    *
    */
    //@ManyToOne(cascade = arrayOf(CascadeType.ALL),fetch= FetchType.EAGER)
    //@JoinColumn(name="customer_id")
    //@JsonBackReference
    //val customer: Customer? = null,

    @OneToMany(mappedBy="purchase", cascade=arrayOf(CascadeType.ALL), fetch=FetchType.EAGER)
    @JsonManagedReference
    var purchasesLines: List<PurchaseLine> = emptyList()
)

PurchaseLine代码：

package com.moises.kotlinstoreapi.model

import com.fasterxml.jackson.annotation.JsonBackReference
import com.fasterxml.jackson.annotation.JsonManagedReference
import javax.persistence.*
import javax.validation.constraints.NotEmpty

@Entity
@Table(name="purchase_lines")
data class PurchaseLine(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private val id: Long=0,
    @NotEmpty
    val quantity: Int = 1,

    /**
    * Relations
    *
    */
    @OneToOne(cascade = arrayOf(CascadeType.ALL))
    @JoinColumn(name = "product_id")
    @JsonManagedReference
    val product: Product? = null,

    @ManyToOne(cascade = arrayOf(CascadeType.ALL),fetch= FetchType.EAGER)
    @JoinColumn(name="purchase_id")
    @JsonBackReference
    var purchase: Purchase? = null
)

我在IntelliJ中与Ubuntu中的Maven和OpenJDK 11一起使用。

我的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>

Kotlin SpringBoot和JPA-关系OneToMany-ManyToOne的问题

0 个答案: