Spring 引导错误：@OneToOne 或 @ManyToOne 引用未知实体

Question

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.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

Answer 1

As the error suggests, you are annotating (referencing) a non-persistent type within anohter JPA Entity.

The EarthquakeEntity should be the mapped type instead of EarthquakeDto :

@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
}

You should then configure your ModelMapper so that the DistanceDto gets automatically mapped to DistanceEntity as well when mapping the EarthquakeDto to a EarthquakeEntity instance.

Note that you issue has nothing to do with the Spring framework itself and is a pure JPA - Hibernate error.