代码之家 › 专栏 › 技术社区 › Andrea D'Attero

创建名为“entityManagerFactory”的bean时出错:Property“com.example.shopping.models.Account.orders”不是集合

spring-data-jpa maven spring-boot spring java

Andrea D'Attero · 技术社区 · 2 年前

大家好,我是Springboot的初学者,我需要一些设置方面的帮助,不知何故,当我启动spring应用程序时,它会抛出以下错误:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name
'entityManagerFactory' defined in class path resource 
[org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]:
Property 'com.example.shopping.models.Account.orders' is not a collection and
may not be a '@OneToMany', '@ManyToMany', or '@ElementCollection'

Account模型如下所示:

package com.example.shopping.models;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.OneToMany;

@Entity
public class Account {
    
    @Id
    @GeneratedValue(strategy= GenerationType.SEQUENCE, generator="account_id")
    private Long id;

    public String name;

    public String email;

    @OneToMany()
    public Iterable<Order> orders;

}

我还有如下订单模型:

package com.example.shopping.models;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.ManyToOne;
import jakarta.persistence.OneToMany;

@Entity
public class Order {
    @Id
    @GeneratedValue(strategy= GenerationType.SEQUENCE, generator="order_id")
    private Long id;
    
    @Id
    public Long accountId;
    
    @ManyToOne
    public Account account;

    @OneToMany()
    public Iterable<ProductOrder> products;
}

这是application.properties文件:

## default connection pool
spring.datasource.hikari.connectionTimeout=20000
spring.datasource.hikari.maximumPoolSize=5

## PostgreSQL
spring.datasource.url=jdbc:postgresql://localhost:5432/shopping?createDatabaseIfNotExist=true&amp;amp;useUnicode=true&amp;amp;characterEncoding=utf-8&amp;amp;autoReconnect=true
spring.datasource.username=postgres
spring.datasource.password=test

# create and drop table, good for testing, production set to none or comment it
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.generate-ddl=true
app.db.init.enabled=true
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect

这是pom.xml文件:

<?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>3.2.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>shopping</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>shopping</name>
    <description>Shopping project for Spring Boot</description>
    <properties>
        <java.version>21</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>          
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>3.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

我没有创建数据库,我认为它应该由Spring自动创建,表也正确吗?

2 回复 | 直到 2 年前

Andrei Lisa 2 年前

你得到的错误告诉你必须改变什么。

属性“com.example.shopping.models.Account.orders”不是集合,并且可能不是“@OneToMany”、“@ManyToMany”或 '@ElementCollection'

要修复它,您必须更换

    @OneToMany
    public Iterable<Order> orders;

收件人:

@OneToMany
public List<Order> orders;

而且

    @OneToMany
    public Iterable<ProductOrder> products;

使用 List 而不是 Iterable

mentallurg 2 年前

错误消息解释了问题所在:Account.orders不是集合。将Account.orders定义为集合,例如,定义为集合。

@OneToMany
private Set<Order> orders;