问题

I'm a physics engineer and I have to do some research on earthquakes, for that I'm building a software to perform some calculations. I have experience with java and android, but I'm having some difficulties with Spring Boot framework. I need to send to MySql database some important earthquakes, to analyze them. I have two entities, one is for the earthquakes and one is for a list of distances near the epicenter. Currently my problem consists in @OneToMany and @ManyToOne relationship where the error starts. I have for each entities also a DTO like below:
EarthquakeEntity:

@Entity(name = "earthquakes")
public class EarthquakeEntity implements Serializable {

    @Id
    @GeneratedValue
    private long id;

    @Column(nullable = false)
    private String earthquakeId;

    @Column(nullable = false)
    private float magnitude;

    @Column(nullable = false, length = 120)
    private String region;

    @Column(nullable = false, length = 50)
    private String dateTime;

    @Column(nullable = false, length = 50)
    private String location;

    @Column(nullable = false, length = 50)
    private Integer depth;

    @OneToMany(mappedBy = "earthquakeDetails", cascade = CascadeType.ALL)
    private List<DistancesEntity> distances;

    // getters and setters
}

Earthquake DTO:

public class EarthquakeDto implements Serializable {
    private long id;
    private String earthquakeId;
    private float magnitude;
    private String region;
    private String dateTime;
    private String location;
    private Integer depth;
    private List<DistanceDto> distances;
    
    // getters and setters
}

and for the distance:

DistanceEntity:

@Entity(name = "distances")
public class DistancesEntity implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    @Column(nullable = false, length = 30)
    private String distanceId;

    @Column(nullable = false, length = 120)
    private String distance;

    @Column(nullable = false, length = 50)
    private Integer population;

    @Column(nullable = false, length = 50)
    private String localTime;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "earthquakes_id", nullable = false)
    private EarthquakeDto earthquakeDetails;
 
    // getters and setters
}

DistanceDTO:

public class DistanceDto implements Serializable {
    private long id;
    private String distanceId;
    private String distance;
    private Integer population;
    private String localTime;
    private EarthquakeDto earthquakeDetails;

    // getters and setters
}

And in my service I have the logic for adding the earthquakes to the database,

EarthquakeServiceImpl.java

@Override
public EarthquakeDto addEarthquake(EarthquakeDto earthquake) {
    for (int i = 0; i < earthquake.getDistances().size(); i++) {
        DistanceDto distance = earthquake.getDistances().get(i);
        distance.setEarthquakeDto(earthquake);
        distance.setDistanceId(utils.generateQuakeDistanceID(30));
        earthquake.getDistances().set(i, distance);
    }

    ModelMapper modelMapper = new ModelMapper();
    EarthquakeEntity earthquakeEntity = modelMapper.map(earthquake, EarthquakeEntity.class);

    String earthquakeId = utils.generateEarthquakeID(30);
    earthquakeEntity.setEarthquakeId(earthquakeId);

    EarthquakeEntity addedEarthquakes = earthquakeRepository.save(earthquakeEntity);

    EarthquakeDto returnQuake = modelMapper.map(addedEarthquakes, EarthquakeDto.class);

    return returnQuake;
}

and my controller

@PostMapping(consumes = { MediaType.APPLICATION_XML_VALUE, MediaType.APPLICATION_JSON_VALUE },
            produces = { MediaType.APPLICATION_XML_VALUE, MediaType.APPLICATION_JSON_VALUE })
public EarthquakeRest addEarthquake(@RequestBody EarthquakeRequestModel earthquakeDetails) throws Exception {
    EarthquakeRest earthquakeRest = new EarthquakeRest();

    ModelMapper modelMapper = new ModelMapper();
    EarthquakeDto quakeDto = modelMapper.map(earthquakeDetails, EarthquakeDto.class);

    EarthquakeDto addedEarthquake = earthquakeService.addEarthquake(quakeDto);
    earthquakeRest = modelMapper.map(addedEarthquake, EarthquakeRest.class);

    return earthquakeRest;
}

I did some research before decided to post my question on stack overflow, but none of them worked for me. The error seems to do with the hibernate, I carefully checked if I had import the annotations from javax.persistence and maven dependencies. Everything seems to be okay, but error persists:

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: @OneToOne or @ManyToOne on com.physicslab.Physics.Lab.io.entity.DistancesEntity.earthquakeDetails references an unknown entity: com.physicslab.Physics.Lab.shared.dto.EarthquakeDto

and another one

Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.physicslab.Physics.Lab.io.entity.DistancesEntity.earthquakeDetails references an unknown entity: com.physicslab.Physics.Lab.shared.dto.EarthquakeDto

I need some advice or suggestions of what I'm doing wrong or if I'm doing a bad practice. I'm also posting my maven dependencies if I did something wring here:

<?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>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.physicslab</groupId>
    <artifactId>Physics-Lab</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>Physics-Lab</name>
    <description>Project and laboratory management for physics projects</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <jjwt.version>0.6.0</jjwt.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>

        <dependency>
            <groupId>io

<details>
<summary>英文:</summary>

I&#39;m a physics engineer and I have to do some research on earthquakes, for that I&#39;m building a software to perform some calculations. I have experience with java and android, but I&#39;m having some difficulties with Spring Boot framework. I need to send to MySql database some important earthquakes, to analyze them. I have two entities, one is for the earthquakes and one is for a list of distances near the epicenter. Currently my problem consists in @OneToMany and @ManyToOne relationship where the error starts. I have for each entities also a DTO like below:
EarthquakeEntity:

@Entity(name = "earthquakes")
public class EarthquakeEntity implements Serializable {

@Id
@GeneratedValue
private long id;

@Column(nullable = false)
private String earthquakeId;

@Column(nullable = false)
private float magnitude;

@Column(nullable = false, length = 120)
private String region;

@Column(nullable = false, length = 50)
private String dateTime;

@Column(nullable = false, length = 50)
private String location;

@Column(nullable = false, length = 50)
private Integer depth;

@OneToMany(mappedBy = "earthquakeDetails", cascade = CascadeType.ALL)
private List<DistancesEntity> distances;

// getters and setters

}

Earthquake DTO:

public class EarthquakeDto implements Serializable {
private long id;
private String earthquakeId;
private float magnitude;
private String region;
private String dateTime;
private String location;
private Integer depth;
private List<DistanceDto> distances;

// getters and setters

}

and for the distance:
DistanceEntity:

@Entity(name = "distances")
public class DistancesEntity implements Serializable {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;

@Column(nullable = false, length = 30)
private String distanceId;

@Column(nullable = false, length = 120)
private String distance;

@Column(nullable = false, length = 50)
private Integer population;

@Column(nullable = false, length = 50)
private String localTime;

@ManyToOne(fetch = FetchType.LAZY, optional = false)
@JoinColumn(name = "earthquakes_id", nullable = false)
private EarthquakeDto earthquakeDetails;

// getters and setters

}

DistanceDTO:

public class DistanceDto implements Serializable {
private long id;
private String distanceId;
private String distance;
private Integer population;
private String localTime;
private EarthquakeDto earthquakeDetails;

// getters and setters

}

And in my service I have the logic for adding the earthquakes to the database,
EarthquakeServiceImpl.java

Override
public EarthquakeDto addEarthquake(EarthquakeDto earthquake) {
for (int i = 0; i < earthquake.getDistances().size(); i++) {
DistanceDto distance = earthquake.getDistances().get(i);
distance.setEarthquakeDto(earthquake);
distance.setDistanceId(utils.generateQuakeDistanceID(30));
earthquake.getDistances().set(i, distance);
}

    ModelMapper modelMapper = new ModelMapper();
    EarthquakeEntity earthquakeEntity = modelMapper.map(earthquake, EarthquakeEntity.class);

    String earthquakeId = utils.generateEarthquakeID(30);
    earthquakeEntity.setEarthquakeId(earthquakeId);

    EarthquakeEntity addedEarthquakes = earthquakeRepository.save(earthquakeEntity);

    EarthquakeDto returnQuake = modelMapper.map(addedEarthquakes, EarthquakeDto.class);

    return returnQuake;
}

and my controller

@PostMapping(consumes = { MediaType.APPLICATION_XML_VALUE, MediaType.APPLICATION_JSON_VALUE },
produces = { MediaType.APPLICATION_XML_VALUE, MediaType.APPLICATION_JSON_VALUE })
public EarthquakeRest addEarthquake(@RequestBody EarthquakeRequestModel earthquakeDetails) throws Exception {
EarthquakeRest earthquakeRest = new EarthquakeRest();

    ModelMapper modelMapper = new ModelMapper();
    EarthquakeDto quakeDto = modelMapper.map(earthquakeDetails, EarthquakeDto.class);

    EarthquakeDto addedEarthquake = earthquakeService.addEarthquake(quakeDto);
    earthquakeRest = modelMapper.map(addedEarthquake, EarthquakeRest.class);

    return earthquakeRest;
}

I did some research before decided to post my question on stack overflow, but none of them worked for me. The error seems to do with the hibernate, I carefully checked if I had import the annotations from javax.persistence and maven dependencies. Everything seems to be okay, but error persists:

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: @OneToOne or @ManyToOne on com.physicslab.Physics.Lab.io.entity.DistancesEntity.earthquakeDetails references an unknown entity: com.physicslab.Physics.Lab.shared.dto.EarthquakeDto

and another one

Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.physicslab.Physics.Lab.io.entity.DistancesEntity.earthquakeDetails references an unknown entity: com.physicslab.Physics.Lab.shared.dto.EarthquakeDto

I need some advice or suggestions of what I'm doing wrong or if I'm doing a bad practice. I'm also posting my maven dependencies if I did something wring here:

<?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&quot;>
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.physicslab</groupId>
<artifactId>Physics-Lab</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Physics-Lab</name>
<description>Project and laboratory management for physics projects</description>

<properties>
	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
	<java.version>1.8</java.version>
	<jjwt.version>0.6.0</jjwt.version>
</properties>

<dependencies>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-web</artifactId>
	</dependency>

	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-security</artifactId>
	</dependency>

	<dependency>
		<groupId>io.jsonwebtoken</groupId>
		<artifactId>jjwt</artifactId>
		<version>${jjwt.version}</version>
	</dependency>

	<dependency>
		<groupId>org.apache.commons</groupId>
		<artifactId>commons-lang3</artifactId>
		<version>3.3.2</version>
	</dependency>

	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-data-jpa</artifactId>
		<version>2.3.1.RELEASE</version>
	</dependency>


	<dependency>
		<groupId>com.google.code.gson</groupId>
		<artifactId>gson</artifactId>
		<version>2.8.6</version>
	</dependency>

	<dependency>
		<groupId>org.hibernate</groupId>
		<artifactId>hibernate-validator</artifactId>
		<version>6.0.10.Final</version>
	</dependency>

	<dependency>
		<groupId>org.modelmapper.extensions</groupId>
		<artifactId>modelmapper-spring</artifactId>
		<version>2.3.0</version>
	</dependency>

	<dependency>
		<groupId>commons-beanutils</groupId>
		<artifactId>commons-beanutils</artifactId>
		<version>1.9.4</version>
	</dependency>

	<dependency>
		<groupId>org.passay</groupId>
		<artifactId>passay</artifactId>
		<version>1.3.0</version>
	</dependency>

	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-databind</artifactId>
		<version>2.11.1</version>
	</dependency>

	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-core</artifactId>
		<version>2.11.1</version>
	</dependency>

	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-annotations</artifactId>
		<version>2.11.1</version>
	</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>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
		</plugin>
	</plugins>
</build>

</project>

Maybe someone can suggest me some books to read about Spring Boot Framework because the tutorials treat differently and cannot understand well the concepts.
Thanks in advance

</details>


# 答案1
**得分**: 2

如错误提示所示，您正在在另一个JPA实体中对非持久性类型进行注释（引用）。

`EarthquakeEntity` 应该是映射的类型，而不是 `EarthquakeDto`：

```java
@Entity(name = "distances")
public class DistancesEntity implements Serializable {

    // 其他字段

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "earthquakes_id", nullable = false)
    private EarthquakeEntity earthquakeDetails;

    // 获取器和设置器
}

然后，您应该配置您的 ModelMapper 以便在将 EarthquakeDto 映射到 EarthquakeEntity 实例时，DistanceDto 也自动映射到 DistanceEntity。

请注意，您的问题与Spring框架本身无关，而是纯粹的JPA - Hibernate错误。

@Entity(name = "distances")
public class DistancesEntity implements Serializable {

    // other fields

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "earthquakes_id", nullable = false)
    private EarthquakeEntity earthquakeDetails;
 
    // getters and setters
}