无法在 Java EE 中使用 MySQL 和 TomEE 配置 Hibernate（方言错误？）

Question

我正在学习 Java EE 并且已经有 2 天了我一直在努力配置 Hibernate 以在一个简单的 Java EE 中使用 TomEE 服务器上的 MySQL 数据库网络应用程序。

Hibernate 版本：5.4.10.Final（核心和实体管理器依赖项）
Java EE API: 8.0
MySQL版本：8.0.19
TomEE 版本：8.0.1（TomEE 嵌入在 tomee-embedded-maven-plugin 中）

我有 2 个简单实体：Car 和 Seat，具有从 Car 到 Seat(s) 的单向 @OneToMany 关系。 Color 和 EngineType 是普通枚举，而 Specification 是这两个枚举的值对象）。注意：FetchType.EAGER 在@OneToMany 中用于学习目的，我知道这通常不是一个好的解决方案。

当我尝试配置 persistence.xml 文件时，尽管指定了所有内容 "as for MySQL"，Hibernate 似乎仍然使用默认的 HSQLDB syntax/dialect/engine 结果，我在模式创建期间收到错误 :

[INFO] TomEE embedded started on localhost:8080
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL8Dialect
Hibernate: alter table Seat drop foreign key FKkkm9pdx9e1t9jva76n9tqhhqv
mar 06, 2020 1:48:31 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "alter table Seat drop foreign key FKkkm9pdx9e1t9jva76n9tqhhqv" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table Seat drop foreign key FKkkm9pdx9e1t9jva76n9tqhhqv" via JDBC Statement
(...)
Caused by: java.sql.SQLSyntaxErrorException: user lacks privilege or object not found: PUBLIC.SEAT
(...)
Caused by: org.hsqldb.HsqlException: user lacks privilege or object not found: PUBLIC.SEAT     // what is going on here???

对于以后的 Hibernate SQL 创建 DDL 命令，我还：

Hibernate: create table Car (identifier bigint not null auto_increment, color varchar(255), engineType varchar(255), primary key (identifier)) engine=InnoDB
mar 06, 2020 1:48:31 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "create table Car (identifier bigint not null auto_increment, color varchar(255), engineType varchar(255), primary key (identifier)) engine=InnoDB" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table Car (identifier bigint not null auto_increment, color varchar(255), engineType varchar(255), primary key (identifier)) engine=InnoDB" via JDBC Statement
(...)
Caused by: java.sql.SQLSyntaxErrorException: unexpected token: AUTO_INCREMENT
(...)
Caused by: org.hsqldb.HsqlException: unexpected token: AUTO_INCREMENT   // definitely something messed up, this is a correct MySQL token

当我省略所有 "MySQL stuff"（驱动程序和方言），并让 Hibernate 使用默认的 HSQLDB 时，它工作正常...... HSQLDB 的 DDL 是创造的很好。

我尝试了许多不同的配置和替换，通过网络和 SO 谷歌搜索它，但没有找到任何提示为什么 Hibernate 仍然使用非 MySQL 语法（但我不是 100% 确定这是直接的问题的原因）。

我试图在 webapp 下的 resources.xml 文件中指定数据源，但它没有改变任何东西。 此外，我检查了是否 HSQL DB 可以从 Maven 构建中排除，但它附带了 hibernate-core，所以它不容易实现，也许也无济于事。

我之前使用过带 Spring 和 SpringBoot 的 Hibernate，但是带 Java EE 我完全迷失在这里，这就是我问这个问题的原因。

任何人都可以帮助解决这个问题并就所有这些的正确配置提供一些建议吗？

我在 resources/META-INF 下的 persistence.xml 看起来像这样：

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.2"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
    <persistence-unit name="my-persistence-unit" transaction-type="JTA">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <jta-data-source>java:openejb/Resource/myJtaDatabase</jta-data-source>
        <!-- Entity classes -->
        <class>com.example.javaeecourse.entity.Car</class>
        <class>com.example.javaeecourse.entity.Seat</class>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <properties>
            <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/javaeecourse?serverTimezone=UTC" />
            <property name="hibernate.connection.username" value="root" />
            <property name="hibernate.connection.password" value="admin" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL8Dialect" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.hbm2ddl.auto" value="create"/>
            <property name="tomee.jpa.factory.lazy" value="true" />
            <!--<property name="tomee.jpa.cdi=false" value="false" />-->
        </properties>
    </persistence-unit>
</persistence>

汽车实体：

package com.example.javaeecourse.entity;

import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

import static com.example.javaeecourse.entity.Car.FIND_ALL;

@Getter
@Setter
@Entity
@Table(name = "cars")
@NamedQuery(name = FIND_ALL, query = "SELECT car FROM Car car")
@NoArgsConstructor
public class Car {

    public static final String FIND_ALL = "Car.findAll";

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long identifier;

    @Enumerated(EnumType.STRING)
    private Color color;
    @Enumerated(EnumType.STRING)
    private EngineType engineType;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @JoinColumn(name = "car", nullable = false)
    private Set<Seat> seats = new HashSet<>();
}

座位实体：

package com.example.javaeecourse.entity;

import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import javax.persistence.*;

@Entity
@Table(name = "seats")
@NoArgsConstructor
@Getter
@Setter
public class Seat {

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

    private String seatMaterial;

    public Seat(String seatMaterial) {
        this.seatMaterial = seatMaterial;
    }
}

CarManufacturer class（@Stateless EJB，调用 EntityManager 的地方）：

package com.example.javaeecourse.boundary;

import com.example.javaeecourse.control.CarFactory;
import com.example.javaeecourse.entity.Car;
import com.example.javaeecourse.entity.CarCreatedEvent;
import com.example.javaeecourse.entity.Specification;

import javax.ejb.Stateless;
import javax.enterprise.event.Event;
import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import java.util.List;

@Stateless
public class CarManufacturer {

    @Inject
    CarFactory carFactory;

    @Inject
    Event<CarCreatedEvent> carCreatedEvent;

    @PersistenceContext
    EntityManager entityManager;

    public Car manufactureCar(Specification specification) {
        Car car = carFactory.createCar(specification);
        entityManager.persist(car);
        carCreatedEvent.fire(new CarCreatedEvent(car.getIdentifier()));
        return car;
    }

    public List<Car> retrieveCars() {
        return entityManager.createNamedQuery(Car.FIND_ALL, Car.class).getResultList();
    }
}

CarFactoryclass，实例化实体：

package com.example.javaeecourse.control;

import com.example.javaeecourse.entity.*;

import javax.inject.Inject;

public class CarFactory {

    @Inject
    @DefaultCarColor
    Color randomCarColor;

    @Inject
    @DefaultCarEngineType
    EngineType randomCarEngineType;

    public Car createCar(Specification specification) {
        Car car = new Car();
        car.setColor(specification.getColor() == null ? randomCarColor : specification.getColor());
        car.setEngineType(specification.getEngineType() == null ? randomCarEngineType : specification.getEngineType());
        Seat seat = new Seat("Leather");
        car.getSeats().add(seat);
        return car;
    }
}

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.example</groupId>
  <artifactId>javaeecourse</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>Java EE Course App</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <failOnMissingWebXml>false</failOnMissingWebXml>
  </properties>

  <dependencies>
    <dependency>
      <groupId>javax</groupId>
      <artifactId>javaee-api</artifactId>
      <version>8.0</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <scope>runtime</scope>
      <version>8.0.19</version>
    </dependency>
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.4.10.Final</version>
    </dependency>
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-entitymanager</artifactId>
      <version>5.4.10.Final</version>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.12</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.jaxrs</groupId>
      <artifactId>jackson-jaxrs-json-provider</artifactId>
      <version>2.9.0</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>javaeecourse</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <groupId>org.apache.tomee.maven</groupId>
          <artifactId>tomee-embedded-maven-plugin</artifactId>
          <version>8.0.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

如有任何帮助，我将不胜感激。

Answer 1

感谢@areus在问题评论中提供的提示，我得以解决此案。如果以后有人遇到类似问题，我会在这里发布答案。

有 1 个主要问题和 1 个 "bad practice" 问题。

主要问题是我使用的是 JTA 事务类型并通过 JNDI 名称引用了 jta-data-source，但是 resources.xml 位于 webapp 而不是 resources/META-INF 下。 我将 resource.xml 移动到 META-INF 后，可以正确创建数据库并持久化实体。

此外，在我的配置中，我为 MySQL 8 使用了一个已弃用的 JDBC 驱动程序。根据 this 文档，自 MySQL 8.0 以来，驱动程序是现在 com.mysql.cj.jdbc.Driver，而不是 com.mysql.jdbc.Driver。

我也删除了不必要的属性，所以配置现在很清楚，一切正常。

resources/META-INF/persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.2"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
    <persistence-unit name="my-persistence-unit" transaction-type="JTA">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <jta-data-source>jdbc/javaeecourse</jta-data-source>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL8Dialect"/>
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
            <property name="tomee.jpa.factory.lazy" value="true"/>
        </properties>
    </persistence-unit>
</persistence>

resources/META-INF/resources.xml

<?xml version="1.0" encoding="UTF-8"?>
<tomee>
<Resource id="jdbc/javaeecourse" type="javax.sql.DataSource">
    JdbcDriver = com.mysql.cj.jdbc.Driver
    JdbcUrl = jdbc:mysql://localhost:3306/javaeecourse?serverTimezone=UTC
    UserName = root
    Password = admin
    jtaManaged = true
</Resource>
</tomee>

这里还有一个great article关于JTA/RESOURCE_LOCAL事务类型以及jta-data-source和non-jta-data-source的配置，帮助我理解了细节。

无法在 Java EE 中使用 MySQL 和 TomEE 配置 Hibernate（方言错误？）

Cannot configure Hibernate with MySQL and TomEE in Java EE (wrong dialect?)

mysql

hibernate

jpa

apache-tomee

java-ee-8