spring - 在 Spring Boot Web 应用程序中创建名称为 'entityManagerFactory' 的 bean 时出错

Question

我是 Spring 引导编码的初学者当我运行 spring boot web 应用程序时，出现以下错误。

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 java.lang.ClassCastException: org.hibernate.mapping.SingleTableSubclass cannot be cast to org.hibernate.mapping.RootClass

我正在使用 STS Eclipse 和 MySql 数据库

我在 Application.Properties 中的连接字符串是

spring.datasource.url=jdbc:mysql://localhost:3306/dreamhospital?zeroDateTimeBehavior=CONVERT_TO_NULL&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.main.banner-mode=off

server.port=8100

这是我的 pom.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>2.2.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.DreamHospital</groupId>
    <artifactId>DreamHospital</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>DreamHospital</name>
    <description>Demo project for Spring Boot</description>
<properties>
    <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>

        <java.version>1.8</java.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-mail</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-web-services</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.session</groupId>
            <artifactId>spring-session-core</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.12</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>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
        <groupId>org.hibernate.validator</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>6.0.16.Final</version>
    </dependency>
    </dependencies>

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

</project>

这是我的实体类:这是患者实体:

@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@Entity
@DiscriminatorValue("patient")
public class patient implements Serializable{
@Id
private int id;
private String nom;
private String prenom;

@ManyToOne
@JoinColumn(name="idLit")
lit lit;
@ManyToOne
@JoinColumn(name="idM")
medecin medecin;
}

这是用户实体:

@Entity
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="fonction" , discriminatorType=DiscriminatorType.STRING,length=10)
public class User implements Serializable {
@Id
private String UserName;
private String Password;
@Column(name="fonction", insertable = false, updatable = false)

protected String fonction;

这是 medecin 实体:

@Data
@Entity
@DiscriminatorValue("medecin")
public class medecin extends User implements Serializable  {
@Id @GeneratedValue
private UUID idM;
private String nom;
private String specialite;
@OneToMany(mappedBy="idM")
List<patient> patients;
}

我尝试了stackoverflow中提出的许多解决方案，但没有奏效

Answer 1

显然 User 和 medecin 的映射有问题，你不能在父类(super class)中有 @Id 和另一个 @Id在子类中。从子类 (medecin) 的 idM 中删除 @Id 应该防止异常。