使用 Hibernate ORM 时出现未知实体错误

Question

我正在编写一个简单的程序来在 Apache NetBeans 17 上使用 Gradle 8.0 测试和学习 Hibernate ORM。我将使用 H2 DB，它可以用作嵌入式数据库。

我编写的程序将在安装了Java 8的计算机上运行，所以我必须使用兼容Java 8的最新Hibernate版本。因此，我选择的技术版本如下：

• Hibernate = org.hibernate.orm:hibernate-java8:6.0.0.Alpha7（最后一个 java8 兼容版本）
• H2 DB = com.h2database:h2:2.2.224
• 雅加达 = jakarta.persistence:jakarta.persistence-api:3.0.0
• ShadowJar = com.github.johnrengelman:shadow:8.1.1（用于生成单个 jar）

Main.java

import java.util.List;
import org.mypackage.database.*;
import org.hibernate.Session;

import org.hibernate.Transaction;

public class Main {
    public static void main(String[] args) {

        Student student = new Student("John", "Cena", "[email protected]");
        
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            System.out.println("INFO: Session opened");
            transaction = session.beginTransaction();
            session.save(student);
            transaction.commit();
        } catch (Exception e) {
            System.out.println("ERROR" + e.getMessage());
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }

        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            List < Student > students = session.createQuery("from Student", Student.class).list();
            students.forEach(s -> System.out.println(s.getFirstName()));
        } catch (Exception e) {
            System.out.println("ERROR" + e.getMessage());
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }
}

学生.java

import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;

@Entity
@Table(name = "student")
public class Student{

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private int id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;

    @Column(name = "email")
    private String email;

    public Student() {

    }

    public Student(String firstName, String lastName, String email) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]";
    }
}

HibernateUtils.java

package org.mypackage.database;

import org.hibernate.SessionFactory;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

public class HibernateUtil {
    private static StandardServiceRegistry registry;
    private static SessionFactory sessionFactory;

    public static SessionFactory getSessionFactory() {
        if (sessionFactory == null) {
            try {
                final StandardServiceRegistry registry = new StandardServiceRegistryBuilder().build();
        try {
                    sessionFactory = new MetadataSources(registry)
                            .addAnnotatedClass(Student.class)
                            .buildMetadata()
                            .buildSessionFactory();
        }
        catch (Exception e) {
            StandardServiceRegistryBuilder.destroy(registry);
        }
                
            } catch (Exception e) {
                e.printStackTrace();
                if (registry != null) {
                    StandardServiceRegistryBuilder.destroy(registry);
                }
            }
        }
        
        return sessionFactory;
    }

    public static void shutdown() {
        if (registry != null) {
            StandardServiceRegistryBuilder.destroy(registry);
        }
    }
}

休眠.属性

# Database connection settings
hibernate.connection.driver_class=org.h2.Driver
hibernate.connection.url=jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1
hibernate.connection.username=sa
hibernate.connection.password=
hibernate.connection.pool_size=1

hibernate.dialect=org.hibernate.dialect.H2Dialect

# Echo all executed SQL to console
hibernate.show_sql=true
hibernate.format_sql=true
hibernate.highlight_sql=true

hibernate.hbm2ddl.auto=create-drop

# Automatically export the schema
hibernate.current_session_context_class=thread
hibernate.hbm2ddl.auto=create
hibernate.dbcp.initialSize=5
hibernate.dbcp.maxTotal=20
hibernate.dbcp.maxIdle=10
hibernate.dbcp.minIdle=5
hibernate.dbcp.maxWaitMillis=-1

构建.gradle

buildscript {
    repositories {
        gradlePluginPortal()
    }
    dependencies {
        classpath 'com.github.johnrengelman:shadow:8.1.1'
    }
}

plugins {
    id 'com.github.johnrengelman.shadow' version '8.1.1'
    id 'java'
    id 'application'
}

apply plugin: 'com.github.johnrengelman.shadow'
apply plugin: 'java'

mainClassName = 'org.mypackage.Main'
group = 'org.mypackage'
version = '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.hibernate.orm:hibernate-java8:6.0.0.Alpha7'
    implementation 'com.h2database:h2:2.2.224'
    implementation 'jakarta.persistence:jakarta.persistence-api:3.0.0'

    testImplementation platform('org.junit:junit-bom:5.9.1')
    testImplementation 'org.junit.jupiter:junit-jupiter'
}

test {
    useJUnitPlatform()
}

compileJava   {
  sourceCompatibility = '1.8'
  targetCompatibility = '1.8'
}

我正在使用在互联网上找到的代码。然而，尽管一切都是正确的，但我收到以下错误。我已经搜索了几天，但没有任何改变，我什至没有收到不同的错误。我写在这里作为最后的手段。如果您希望我添加任何其他信息，请在您的帖子中注明。

Answer 1

正如 @MarkRotteveel 上面提到的，当我使用 Hibernate 5.6.15.Final 和 Jakarta 2.3.3 时，我的问题得到了解决。我将这篇文章标记为帮助其他人的解决方案。