Spring：创建在类路径资源中定义的名称为“entityManagerFactory”的bean时出错

Posted 2023-02-26

【中文标题】Spring：创建在类路径资源中定义的名称为“entityManagerFactory”的bean时出错

【英文标题】：Spring : Error creating bean with name 'entityManagerFactory' defined in class path resource

【发布时间】：2019-07-02 03:07:57

【问题描述】：

我正在尝试使用 spring jpa 在我的数据库上的两个不同表之间建立关系。但是，每次我尝试执行 @OnetoMany 或 @ManytoOne 时，都会收到标题中提到的错误。

学生：

    package EIC.com.example.Backend.Entity;
    import org.hibernate.annotations.Cascade;
    import javax.persistence.*;

    @Entity
    @Table(name = "etudiant")

    public class Student 
        @Id
        @Column(name="Apogee")
        private int id;
        @Column(name="Prenom")
        private String first_name;
        @Column(name="Nom")
        private String last_name;
        @Column(name="Classement")
        private int rank;
        @Column(name="Filiere")
        private String speciality;
        @ManyToOne
        @Column(name = "Offre")
        private Offer school; 
        /* GETTERS SETTERS CONSTRUCTORS */
    

报价：

    package EIC.com.example.Backend.Entity;
    import javax.persistence.*;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    @Entity
    public class Offer 
        @Id
        @Column(name = "ID_OFFRE")
        private int id;
        @Column(name = "Type")
        private int type; // 0 for DD 1 for MOBILITY
        @Column(name = "Etablissement")
        private String school;
        @Column(name = "Filiere_Concerne")
        private String target;
        @Column(name = "Nb_place")
        private int seats;
        @Column(name = "Delai")
        private Date limit;
        @OneToMany
        @JoinColumn(name = "Offre")
        private List<Student> students=new ArrayList<>();
        /* GETTERS SETTERS CONSTRUCTORS */
    

依赖：

http://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0 org.springframework.boot spring-boot-starter-parent 2.1.2.发布 EIC.com.example 后端 0.0.1-快照 后端 带有 Spring Boot 和 Angular 的 EIC 项目

<properties>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-cache</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-data-rest</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-rest-hal-browser</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.session</groupId>
        <artifactId>spring-session-core</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.39</version>
        <scope>runtime</scope>
    </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>

【问题讨论】：

对于这种类型的错误，通常在堆栈跟踪的下方有一个“Caused by”，它会告诉您无法创建 entityManagerFactory bean 的更具体原因。看看，你可以在这里发帖

【参考方案1】：

我认为您看到的错误与您发布的 bean 的配置无关。 Boot 正在代表您创建此 entityManager，但无法成功。

检查this post - 这可能是关键。

【参考方案2】：

你不能同时拥有@Column和@ManyToOne

使用@JoinColumn 代替@Column。 您的学生类应如下所示：

@Entity
@Table(name = "etudiant")

    public class Student 
        @Id
        @Column(name="Apogee")
        private int id;
        @Column(name="Prenom")
        private String first_name;
        @Column(name="Nom")
        private String last_name;
        @Column(name="Classement")
        private int rank;
        @Column(name="Filiere")
        private String speciality;
        @ManyToOne
        @JoinColumn(name = "Offre")
        private Offer school; 
        /* GETTERS SETTERS CONSTRUCTORS */