如何在 Hibernate 的复合主键中自动增加 Id？答案

【问题标题】：How to autoincrement an Id in a composite primary key in Hibernate?如何在 Hibernate 的复合主键中自动增加 Id？
【发布时间】：2019-05-04 20:01:00
【问题描述】：

我有一个包含复合主键的表 - groupId 和 batchId。实体类看起来像：

@Entity(name="EMPLOYEE")
public class Employee {

    @EmbeddedId
    private EmployeePK employeePK;

    //Other columns and their getters and setters
    //Getters and setters
}

复合PK：

@Embeddable
public class EmployeePK implements Serializable {

    private long groupId;
    private long batchId;

    @GeneratedValue(strategy=GenerationType.AUTO)
    public long getBatchId() {
        return batchId;
    }

    public void setBatchId(long batchId) {
        this.batchId = batchId;
    }
}

我正在尝试自动增加批次 ID，以便插入新记录。

//For saving
Employee employee = new Employee();
EmployeePK pk = new IRAmendmentBatchesPK();
pk.setBatchId(0);
pk.setGroupId(4388);

Employee employee = employeeRepository.save(employee);


//Repository Interface
public interface EmployeeRepository extends JpaRepository<Employee, EmployeePK>{

}

我明确将 batchId 设置为 0，希望在保存（插入）期间在 batchId 中设置自动递增值。截至目前，此代码将保存一个新条目，batchId 为 0。

【问题讨论】：

看起来hibernate不支持..forum.hibernate.org/viewtopic.php?f=1&t=1006818..什么是hibernate版本？
你也不应该手动设置id..
@secretsuperstar 那么，有没有我可以做到这一点？
我有一个使用 @IdClass 的工作解决方案，但它在内存数据库中使用 h2，但看起来不适用于 mysql DB。我可以在这里发布，如果你愿意，你可以尝试一下口语。我正在使用hibernate 5和spring 5。我认为spring应该无关紧要。
发表了答案

标签： java oracle hibernate crud

【解决方案1】：

正如我在评论中提到的，我使用了@IdClass，它在我尝试在hsqldb 内存数据库中工作时工作，但在mysql 中工作失败。

请注意我使用的是 hibernate 5

您可以尝试一下 oracle，我不记得了，但它应该可以工作。但是，如果有的话，请检查该方法是否有任何缺点。

pom.xml

<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.techdisqus</groupId>
    <artifactId>spring5-mvc-hibernate-example</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <properties>
        <failOnMissingWebXml>false</failOnMissingWebXml>
        <spring.version>5.0.0.RELEASE</spring.version>
        <hibernate.version>5.2.11.Final</hibernate.version>
        <hibernate.validator>5.4.1.Final</hibernate.validator>
        <c3p0.version>0.9.5.2</c3p0.version>
        <jstl.version>1.2.1</jstl.version>
        <tld.version>1.1.2</tld.version>
        <servlets.version>3.1.0</servlets.version>
        <jsp.version>2.3.1</jsp.version>
        <hsqldb.version>1.8.0.10</hsqldb.version>
    </properties>
    <dependencies>
        <!-- Spring MVC Dependency -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- Spring ORM -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- Hibernate ORM -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>${hibernate.version}</version>
        </dependency>

        <!-- Hibernate-C3P0 Integration -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-c3p0</artifactId>
            <version>${hibernate.version}</version>
        </dependency>

        <!-- c3p0 -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>${c3p0.version}</version>
        </dependency>

        <!-- Hibernate Validator -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>${hibernate.validator}</version>
        </dependency>

        <!-- JSTL Dependency -->
        <dependency>
            <groupId>javax.servlet.jsp.jstl</groupId>
            <artifactId>javax.servlet.jsp.jstl-api</artifactId>
            <version>${jstl.version}</version>
        </dependency>

        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>${tld.version}</version>
        </dependency>

        <!-- Servlet Dependency -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${servlets.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- JSP Dependency -->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>${jsp.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- HSQL Dependency -->
          <dependency>
            <groupId>hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <version>${hsqldb.version}</version>
        </dependency>  

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.12</version>
        </dependency>
    </dependencies>

    <build>
        <sourceDirectory>src/main/java</sourceDirectory>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <!-- Embedded Apache Tomcat required for testing war -->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <path>/</path>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Book.java

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.IdClass;
import javax.persistence.Table;

@Entity(name = "Book")
@Table(name = "book")
@IdClass( PK.class )
public class Book {

    @Id
    @Column(name = "registration_number")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long registrationNumber;

    @Id
    @Column(name = "publisher_id")
    private Integer publisherId;

    private String title;

    public Long getRegistrationNumber() {
        return registrationNumber;
    }

    public void setRegistrationNumber(Long registrationNumber) {
        this.registrationNumber = registrationNumber;
    }

    public Integer getPublisherId() {
        return publisherId;
    }

    public void setPublisherId(Integer publisherId) {
        this.publisherId = publisherId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    @Override
    public String toString() {
        return "Book [registrationNumber=" + registrationNumber + ", publisherId=" + publisherId + ", title=" + title
                + "]";
    }
 }

PK.java

import java.io.Serializable;
import java.util.Objects;

public class PK implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 2371758145387850080L;

    private Long registrationNumber;
    private Integer publisherId;

    public PK(Long registrationNumber, Integer publisherId) {
        this.registrationNumber = registrationNumber;
        this.publisherId = publisherId;
    }


    public PK() {
    }

    @Override
    public boolean equals(Object o) {
        if ( this == o ) {
            return true;
        }
        if ( o == null || getClass() != o.getClass() ) {
            return false;
        }
        PK pk = (PK) o;
        return Objects.equals( registrationNumber, pk.registrationNumber ) &&
                Objects.equals( publisherId, pk.publisherId );
    }

    @Override
    public int hashCode() {
        return Objects.hash( registrationNumber, publisherId );
    }
}

hibernate.cfg.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.archive.autodetection">class,hbm</property>
        <property name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</property>
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.connection.driver_class">org.hsqldb.jdbcDriver</property>
        <property name="hibernate.connection.username">sa</property>
        <property name="hibernate.connection.password"></property>
        <property name="hibernate.connection.url">jdbc:hsqldb:mem:test</property>
        <property name="hibernate.hbm2ddl.auto">create</property>

        <property name="hibernate.c3p0.min_size">5</property>
        <property name="hibernate.c3p0.max_size">20</property>
        <property name="hibernate.c3p0.acquire_increment">2</property>
        <property name="hibernate.c3p0.acquire_increment">1800</property>
        <property name="hibernate.c3p0.max_statements">150</property>
    </session-factory>
</hibernate-configuration>

HibernateConfig.java

@Configuration
@EnableTransactionManagement
@ComponentScans(value = { @ComponentScan("com.techdisqus")})
public class HibernateConfig {

    @Autowired
    private ApplicationContext context;

    @Bean
    public LocalSessionFactoryBean getSessionFactory() {
        LocalSessionFactoryBean factoryBean = new LocalSessionFactoryBean();
        factoryBean.setConfigLocation(context.getResource("classpath:hibernate.cfg.xml"));
        factoryBean.setAnnotatedClasses(Book.class);
        return factoryBean;
    }

    @Bean
    public HibernateTransactionManager getTransactionManager() {
        HibernateTransactionManager transactionManager = new HibernateTransactionManager();
        transactionManager.setSessionFactory(getSessionFactory().getObject());
        return transactionManager;
    }

}

BookDAOImpl.java

@Repository
public class BookDAOImpl implements BookDAO {

    @Autowired
    private SessionFactory sessionFactory;

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }




    public void save(Book book) {
        Session session = this.sessionFactory.openSession();
        Transaction tx = session.beginTransaction();
        session.persist(book);
        tx.commit();
        session.close();

    }

}

客户端代码：

public class SpringHibernateMain2 {

    public static void main(String[] args) {

        ApplicationContext appContext = new AnnotationConfigApplicationContext(HibernateConfig.class);

        BookDAO personDAO = appContext.getBean(BookDAO.class);

        Book book = new Book();
        book.setPublisherId(12);
        book.setTitle("t 1");
        //book.setRegistrationNumber(2l);
        personDAO.save(book);

        System.out.println("book::"+book);




        //context.close();

    }

}

与 H 一起使用时来自日志：

Hibernate：调用 hibernate_sequence 的下一个值 Hibernate：插入到书（标题，publisher_id，registration_number）值（？，？，？） book::Book [registrationNumber=1, publisherId=12, title=t 1]

以下是我尝试使用 MySql

时得到的 error

Hibernate：从 hibernate_sequence 中选择 next_val 作为 id_val 更新时间：2018 年 12 月 4 日下午 6:24:53 org.hibernate.id.enhanced.TableStructure$1$1 执行错误：不能读取 hi 值 java.sql.SQLSyntaxErrorException: Table “security.hibernate_sequence”不存在t

我已经在帖子中尝试了接受的答案 Hibernate insert failing when embedded key contains identity column on SQL Server 但没有运气。

【讨论】：

这似乎也不适用于 Oracle。感谢您的回复。
你得到什么错误？你可以试试序列生成器（mysql中有序列，所以不能用）？什么是休眠版本？
我收到如下错误：hibernate_sequence 不存在。休眠版本是 5.0.12。
你可以尝试使用序列生成器。当前代码使用AUTO。看看 Book.java

【解决方案2】：

@Embeddable
public class EmployeePK implements Serializable {

    private long groupId;
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long batchId;

   
    public long getBatchId() {
        return batchId;
    }

    public void setBatchId(long batchId) {
        this.batchId = batchId;
    }

//implements equals and hashcode

}

【讨论】：