Question

在Hibernate 5.2 org.hibernate.Session.saveOrUpdate()中，对于已分离的对象，update不执行save。

使用Hibernate 3.6时，它按预期工作。

这些是重现问题的文件：

实体Person.java：

package model;

import javax.persistence.*;

@Entity
public class Person
{
    @Id
    @GeneratedValue
    private Long id;
    @Column(unique = true)
    private String name;
    private Integer age;

    public void setName(String name)
    {
        this.name = name;
    }

    public void setAge(Integer age)
    {
        this.age = age;
    }
}

DAO界面HibernateTestDao.java：

package model;

public interface HibernateTestDao
{
    void test();
}

和DAO实施HibernateTestDaoImpl.java：

package model;

import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

@Transactional(readOnly = true)
@Repository
public class HibernateTestDaoImpl implements HibernateTestDao
{
    @Autowired
    private SessionFactory sessionFactory;

    @Transactional(readOnly = false)
    @Override
    public void test()
    {
        Person person = new Person();
        person.setName("Joe");
        person.setAge(10);

        Long id = (Long)sessionFactory.getCurrentSession().save(person);

        sessionFactory.getCurrentSession().flush();

        person = sessionFactory.getCurrentSession().get(Person.class, id);

        sessionFactory.getCurrentSession().clear();

        person.setAge(11);

        sessionFactory.getCurrentSession().saveOrUpdate(person);
        sessionFactory.getCurrentSession().flush();

        throw new RuntimeException();
    }

}

主要课程HibernateTest.java：

package test;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import model.HibernateTestDao;

public class HibernateTest
{
    public static void main(String[] args)
    {
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:/applicationContext.xml");

        HibernateTestDao dao = applicationContext.getBean(HibernateTestDao.class);

        dao.test();;

        applicationContext.close();
    }
}

Spring配置文件applicationContext.xml：

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:context="http://www.springframework.org/schema/context"
  xmlns:util="http://www.springframework.org/schema/util"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:tx="http://www.springframework.org/schema/tx"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
        http://www.springframework.org/schema/util
        http://www.springframework.org/schema/util/spring-util-4.3.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    <context:component-scan base-package="model"/>

    <bean id="dataSource"  class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/hibernatetest" />
        <property name="username" value="hibernatetest" />
        <property name="password" value="hibernatetest" />
    </bean>

    <bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
        <property name="packagesToScan">
            <list>
                <value>model</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                <prop key="hibernate.id.new_generator_mappings">false</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.generate_statistics">false</prop>
                <prop key="hibernate.max_fetch_depth">3</prop>
            </props>
        </property>
        <property name="dataSource">
            <ref bean="dataSource"/>
        </property>
    </bean>

    <tx:annotation-driven/>

    <bean id="transactionManager" class="org.springframework.orm.hibernate5.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>

</beans>

最后是pom.xml文件：

<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>ProvaHibernate</groupId>
  <artifactId>ProvaHibernate</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
      <hibernate.version>5.2.12.Final</hibernate.version>
      <spring.version>4.3.12.RELEASE</spring.version>
  </properties>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.7.0</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <dependencies>
      <dependency>
          <groupId>org.hibernate</groupId>
          <artifactId>hibernate-core</artifactId>
          <version>${hibernate.version}</version>
      </dependency>
      <dependency>
          <groupId>org.hibernate</groupId>
          <artifactId>hibernate-validator</artifactId>
          <version>5.3.4.Final</version>
      </dependency>
        <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.45</version>
        </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-beans</artifactId>
          <version>${spring.version}</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>${spring.version}</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-orm</artifactId>
          <version>${spring.version}</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-tx</artifactId>
          <version>${spring.version}</version>
      </dependency>
      <dependency>
          <groupId>org.apache.commons</groupId>
          <artifactId>commons-dbcp2</artifactId>
          <version>2.1.1</version>
      </dependency>
   </dependencies>
</project>

执行时，控制台显示：

    Hibernate: insert into Person (age, name) values (?, ?)
    Hibernate: insert into Person (age, name) values (?, ?)
    Dec 13, 2017 6:26:47 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
    WARN: SQL Error: 1062, SQLState: 23000
    Dec 13, 2017 6:26:47 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
    ERROR: Duplicate entry 'Joe' for key 'person_un'
    Exception in thread "main"
    org.hibernate.exception.ConstraintViolationException: could not execute statement
    ...
    Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException:
    Duplicate entry 'Joe' for key 'person_un'
    ...

如果我删除sessionFactory.getCurrentSession().clear();中的HibernateTestDaoImpl.java语句，让对话中的Person对象显示：

    Hibernate: insert into Person (age, name) values (?, ?)
    Hibernate: update Person set age=?, name=? where id=?

Hibernate documentation表示saveOrUpdate将分离的对象重新附加到会话中：

这是一个Hibernate 5.2错误，我错过了什么。

Answer 1

这不是Hibernate的错误。

在answer之后，我向integrate的方法JpaAnnotationsIntegrator添加了一个句子，引发了问题。增加的句子是：

eventListenerRegistry.prependListeners(EventType.SAVE_UPDATE, new JpaSaveEventListener(callbackRegistry));

更新：我忘了说我没有使用任何监听器，只是安装该服务。我无法理解为什么这会在saveOrUpdate中引发这种行为。如果我将prependListeners更改为appendListeners，那么事情就会正常进行。

为什么在Hibernate 5.2中saveOrUpdate的行为与记录不一致

1 个答案: