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问使用Java、Hibernate和EntityManager的@ transaction中的事务提交问题
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Stack Overflow用户

提问于 2020-05-09 18:10:16

回答 2查看 6K关注 0票数 1

我正在尝试学习Spring，Hibernate和H2数据库一起使用maven来构建代码。目前，我遇到了一些问题，如何正确地使用@ transaction注释来自动启动事务并在entityManager.persist成功完成或回滚时提交事务。

我的测试项目很简单。POJO类是Person，包含名字、姓氏和电子邮件地址。有一个服务类PersonSerice是一个接口，它提供CRUD函数来添加、更改、读取和删除person数据。有一个PersonServiceImpl调用DAO类的方法。在这里，PersonDAOImpl::createPerson方法的示例代码使用

public void createPerson(Person person) {
    entityManager.getTransaction().begin();
    entityManager.persist(person);
    entityManager.getTransaction().commit();
}

一切都如期而至。有一个Hibernate SQL输出。

"Hibernate:调用hibernate_sequence Hibernate的下一个值:插入person (电子邮件、nachname、vorname、id)值(？、?)“

我想要摆脱手动调用entityManager.getTransaction().commit();，所以我尝试在调用DAO方法的ServiceImpl方法上编写@Transactional

    public void createPerson(Person person) {
    entityManager.getTransaction().begin();
    entityManager.persist(person);
    entityManager.getTransaction().commit();
}

现在它不能正常工作了。我只是得到了。“Hibernate:调用hibernate_sequence的下一个值”在数据库中写入了一些东西，但是如果没有手动提交，我就无法列出所有条目或删除它们。因此，我目前不知道出了什么问题，也不知道如何获得@Transactional，自动提交。在这里，Eclipse调试器中显示的部分entityManager内容：

ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler ( entityManager $Proxy26 (id=33) h id=116)

  containerManaged   false

  exceptionTranslator    null      jta    false      synchronizedWithTransaction    false

  target SessionImpl  (id=122)

     actionQueue ActionQueue  (id=306)

     ...         autoJoinTransactions    true

...

我想我的主要问题可能在xml资源文件中，所以我想在这里展示它们。下面是我的Beans.xlm (./src/main/resources/Beans.xml)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:task="http://www.springframework.org/schema/task"
    xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">

   <context:component-scan base-package="maven.springhibernateh2.basic"></context:component-scan>
    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName"
            value="${db.driverClassName}"></property>
        <property name="url" value="${db.url}"></property>
        <property name="username" value="${db.username}"></property>
        <property name="password" value="${db.password}"></property>
    </bean>


    <bean
        class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>database.properties</value>
            </list>
        </property>
        <property name="ignoreUnresolvablePlaceholders" value="true"/>
    </bean>


   <!-- Definition des JpaTransactionManagers -->
   <bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
      <property name="entityManagerFactory" ref="entityManagerFactory" />
   </bean>

   <!-- Acitvation of @Transactional Annotation -->
   <tx:annotation-driven mode="aspectj" transaction-manager="transactionManager" />

   <bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory">
      <property name="persistenceUnitName" value="roland.egger.maven.springhibernate" />
      <property name="dataSource" ref="dataSource" />
   </bean>

    <context:spring-configured />
    <context:annotation-config />

</beans>

一句可能是个问题。"<tx:annotation-driven mode="aspectj" transaction-manager="transactionManager" />"，因为我的pom中没有aspectj依赖项。但是，添加它们并没有改变任何事情，我也不知道要按预期的方式让@Transactional正常工作需要什么。

其他文件。

这是我的(./src/main/resources/META-INF/persistence.xml) persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" 
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.0"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
  <persistence-unit name="roland.egger.maven.springhibernate" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

    <class>maven.springhibernateh2.basic.Person</class>
     <properties>
      <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
      <property name="hibernate.hbm2ddl.auto" value="create" />
      <property name="hibernate.show_sql" value="true" />
      <property name="hibernate.format_sql" value="true" />
    </properties>


  </persistence-unit>
</persistence>

我的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>roland.egger</groupId>
  <artifactId>maven.springhibernateh2.basic</artifactId>
  <version>0.0.1-SNAPSHOT</version>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.6.1</version>
            <configuration>
               <source>1.8</source>
               <target>1.8</target>
            </configuration>
         </plugin>
      </plugins>
   </build>
   <properties>
      <slf4j.version>1.7.30</slf4j.version>
      <spring.version>5.2.5.RELEASE</spring.version>
      <hibernate.version>5.4.15.Final</hibernate.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-core</artifactId>
         <version>${spring.version}</version>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-context</artifactId>
         <version>${spring.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.springframework/spring-orm -->
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-orm</artifactId>
         <version>${spring.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-jdbc</artifactId>
         <version>${spring.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-aspects</artifactId>
         <version>${spring.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-tx</artifactId>
         <version>${spring.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
      <dependency>
         <groupId>com.h2database</groupId>
         <artifactId>h2</artifactId>
         <version>1.4.200</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
      <dependency>
         <groupId>org.hibernate</groupId>
         <artifactId>hibernate-core</artifactId>
         <version>${hibernate.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-entitymanager -->
      <dependency>
         <groupId>org.hibernate</groupId>
         <artifactId>hibernate-entitymanager</artifactId>
         <version>${hibernate.version}</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.hibernate.javax.persistence/hibernate-jpa-2.1-api -->
      <dependency>
         <groupId>org.hibernate.javax.persistence</groupId>
         <artifactId>hibernate-jpa-2.1-api</artifactId>
         <version>1.0.2.Final</version>
      </dependency>
      <dependency>
         <groupId>org.slf4j</groupId>
         <artifactId>slf4j-api</artifactId>
         <version>${slf4j.version}</version>
      </dependency>
      <dependency>
         <groupId>org.slf4j</groupId>
         <artifactId>slf4j-log4j12</artifactId>
         <version>${slf4j.version}</version>
      </dependency>
      <!-- Fuer den RollingFileAppender -->
      <dependency>
         <groupId>log4j</groupId>
         <artifactId>apache-log4j-extras</artifactId>
         <version>1.1</version>
      </dependency>
   </dependencies>
</project>

在这里database.properties

db.driverClassName=org.h2.Driver
db.url=jdbc:h2:mem:test;DB_CLOSE_DELAY=-1
db.username=sa
db.password=

在这里Person.java

package maven.springhibernateh2.basic;

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


@Entity
@Table(name="person")
public class Person {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="id")
    private int personId;

    @Column(name = "vorname")
    private String Vorname;

    @Column(name = "nachname")
    private String Nachname;

    @Column(name = "email")
    private String Emailadresse;
    public int getPersonId() {
        return personId;
    }
    public void setPersonId(int personId) {
        this.personId = personId;
    }
    public String getVorname() {
        return Vorname;
    }
    public void setVorname(String vorname) {
        Vorname = vorname;
    }
    public String getNachname() {
        return Nachname;
    }
    public void setNachname(String nachname) {
        Nachname = nachname;
    }
    public String getEmailadresse() {
        return Emailadresse;
    }
    public void setEmailadresse(String emailadresse) {
        Emailadresse = emailadresse;
    }

    public String toString() {
        return "Person [PersonId=" + personId + ", Vorname=" + Vorname + ", Nachname=" + Nachname + ", Emailadresse=" + Emailadresse + "]";
    }
}

PersonService.java

package maven.springhibernateh2.basic;

import java.util.List;

public interface PersonService {
    public abstract void addPerson(Person person);
    public abstract Person fetchPersonById(int personId);
    public abstract void deletePersonByID(int personId);
    public abstract void updatePersonEmailByID(String newEmail, int personId);
    public abstract List<Person> getAllPersonInfo();
}

PersonServiceImpl.java

package maven.springhibernateh2.basic;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;

@Component("personService")
public class PersonServiceImpl implements PersonService {

    @Autowired
    private PersonDAO personDAO;

    public void setPersonDAO(PersonDAO personDAO) {
        this.personDAO = personDAO;
    }

    @Transactional
    public void addPerson(Person person) {
        personDAO.createPerson(person);
    }

    @Transactional
    public Person fetchPersonById(int personId) {
        return personDAO.getPersonById(personId);
    }

    @Transactional
    public void deletePersonByID(int personId) {
        personDAO.deletePersonByID(personId);
    }

    @Transactional
    public void updatePersonEmailByID(String newEmail, int personId) {
        personDAO.updatePersonEmailByID(newEmail, personId);
    }

    @Transactional
    public List<Person> getAllPersonInfo() {
        return personDAO.getAllPersonData();
    }
}

PersonDAO.java

package maven.springhibernateh2.basic;

import java.util.List;

public interface PersonDAO {
    public abstract void createPerson(Person person);
    public abstract Person getPersonById(int personId);
    public abstract void deletePersonByID(int personId);
    public abstract void updatePersonEmailByID(String newEmail, int personId);
    public abstract List<Person> getAllPersonData();

}

PersonDAOImpl.java

package maven.springhibernateh2.basic;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import javax.persistence.TypedQuery;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;

import org.springframework.stereotype.Repository;


@Repository
public class PersonDAOImpl implements PersonDAO {

    @PersistenceUnit(name = "roland.egger.maven.springhibernate")
    private EntityManagerFactory entityManagerFactory;    

    private EntityManager entityManager;

    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    public EntityManagerFactory getEntityManagerFactory() {
        return entityManagerFactory;
    }

    @PersistenceUnit
    public void setEntityManagerFactory(EntityManagerFactory entityManagerFactory) {
        this.entityManagerFactory = entityManagerFactory;
        this.entityManager = this.entityManagerFactory.createEntityManager();
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }


    public void createPerson(Person person) {
        entityManager.persist(person);
    }

    public Person getPersonById(int personId) {
        Person person = entityManager.find(Person.class, personId);
        return person;
    }

    public void deletePersonByID(int personId) {
        Person person = getPersonById(personId);
        if (person != null) {
            //entityManager.getTransaction().begin();
            entityManager.remove(person);
            //entityManager.getTransaction().commit();
        }
    }

    public void updatePersonEmailByID(String newEmail, int personId) {
        Person person = getPersonById(personId);
        if (person != null)
        { 
            entityManager.getTransaction().begin();
            person.setEmailadresse(newEmail);
            entityManager.getTransaction().commit();
        }
    }

    public List<Person> getAllPersonData() {
        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
        CriteriaQuery<Person> cq = cb.createQuery(Person.class);
        Root<Person> rootEntry = cq.from(Person.class);
        CriteriaQuery<Person> all = cq.select(rootEntry);
        TypedQuery<Person> allQuery = entityManager.createQuery(all);
        return allQuery.getResultList();
    }

}

请原谅我发布了源代码，但我希望它能帮助其他人理解我在做什么，以及如何解决问题，使事务能够正常工作，而无需将它们手动写入代码中。

java

spring

hibernate

transactions

entitymanager

回答 2

Stack Overflow用户

回答已采纳

发布于 2020-05-09 18:35:44

使用@PersistenceUnit时，需要创建/销毁EntityManager并手动管理事务。如果您想使用spring @Transactional，您需要删除由@PersistenceUnit注释的entityManagerFactory，而是在您的entityManager变量上使用@PersistenceContext，如下所示。

@PersistenceContext
private EntityManager entityManager;

原因是，当您使用@PersistenceContext时，您定义了一个容器托管bean(这里是spring管理的)，这样您就不需要显式地提交/回滚您的事务，而在@PersistenceUnit中，您指定要处理事务。

更新：

与最近提到的“当前线程没有实际事务可用的EntityManager”相关：

，您可以从配置中删除mode=" aspectj“，如果您不需要使用aspectj，并且可以依赖spring默认的AOP。在从immediately.
Or中删除mode=" aspectj“之后，您的代码应该工作，调整配置以正确实现Beans.xml。至少您需要将aspectj依赖项添加到您的项目pom中，并将“context:load”定义添加到Beans.xml中。请查看spring事务管理文档以了解aspectj的使用情况.

希望这能有所帮助。

票数 4

Stack Overflow用户

发布于 2020-05-09 20:57:49

我试着回答阿里·盖伦克斯的建议，但我的评论是简短的，我明白了，我在entityManager之后遇到了另一个问题。感谢Ali，我被告知我的PersonDAOImpl类中的@PersistenceUnit对于我的EntityManagerFactory及其setter函数会造成问题，并且应该使用@PersistenceContext。这里是我的PersonDaoImpl新代码的一部分

@Repository
public class PersonDAOImpl implements PersonDAO {

    private EntityManagerFactory entityManagerFactory;    

    @PersistenceContext
    private EntityManager entityManager;

    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    public EntityManagerFactory getEntityManagerFactory() {
        return entityManagerFactory;
    }

    public void setEntityManagerFactory(EntityManagerFactory entityManagerFactory) {
        this.entityManagerFactory = entityManagerFactory;
        this.entityManager = this.entityManagerFactory.createEntityManager();
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }


    public void createPerson(Person person) {
        entityManager.persist(person);
    }
...

现在既没有调用setter setEntityManagerFactory也没有调用setter setEntityManager。此问题发生在createPerson方法调用entityManager.persist(person)期间。entityManager调用引发以下异常：

" javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'persist' call "

在此异常之前，entityManager显示Eclipse调试器中的折叠内容。

entityManager   $Proxy26  (id=40)   
h   SharedEntityManagerCreator$SharedEntityManagerInvocationHandler  (id=47)    
           logger   LogAdapter$Slf4jLocationAwareLog  (id=51)   
           properties   null
           proxyClassLoader Launcher$AppClassLoader  (id=55)
           synchronizedWithTransaction  true    
           targetFactory    $Proxy23  (id=62)

完整的控制台输出是：

INFO  | 2020-05-09 22:44:44,953 |                                      |        | main | maven.springhibernateh2.basic.CRUDTest - Programmanfang... 
 INFO  | 2020-05-09 22:44:45,486 |                                      |        | main | org.hibernate.jpa.internal.util.LogHelper - HHH000204: Processing PersistenceUnitInfo [name: roland.egger.maven.springhibernate] 
 INFO  | 2020-05-09 22:44:45,532 |                                      |        | main | org.hibernate.Version - HHH000412: Hibernate ORM core version 5.4.15.Final 
 INFO  | 2020-05-09 22:44:45,657 |                                      |        | main | org.hibernate.annotations.common.Version - HCANN000001: Hibernate Commons Annotations {5.1.0.Final} 
 INFO  | 2020-05-09 22:44:46,193 |                                      |        | main | org.hibernate.dialect.Dialect - HHH000400: Using dialect: org.hibernate.dialect.H2Dialect 
 Hibernate: 

    drop table if exists person CASCADE 
Hibernate: 

    drop sequence if exists hibernate_sequence
Hibernate: create sequence hibernate_sequence start with 1 increment by 1
Hibernate: 

    create table person (
       id integer not null,
        email varchar(255),
        nachname varchar(255),
        vorname varchar(255),
        primary key (id)
    )
INFO  | 2020-05-09 22:44:46,877 |                                      |        | main | org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator - HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform] 
 INFO  | 2020-05-09 22:44:46,884 |                                      |        | main | org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean - Initialized JPA EntityManagerFactory for persistence unit 'roland.egger.maven.springhibernate' 
 ERROR | 2020-05-09 22:44:46,987 |                                      |        | main | maven.springhibernateh2.basic.CRUDTest - javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'persist' call 
 INFO  | 2020-05-09 22:44:46,987 |                                      |        | main | maven.springhibernateh2.basic.CRUDTest - Programmende... 
 INFO  | 2020-05-09 22:44:46,988 |                                      |        | main | org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean - Closing JPA EntityManagerFactory for persistence unit 'roland.egger.maven.springhibernate'

要使entityManager对当前线程可用，需要什么？

Update:，多亏了Ali的更新建议，我让它工作了:)在我的测试项目中，我选择了最简单的解决方案，没有aspectj。这里改变了我的Beans.xml的部分：.

       <!--  <tx:annotation-driven mode="aspectj" transaction-manager="transactionManager" />  -->
       <tx:annotation-driven transaction-manager="transactionManager" /> 
...
       <aop:config proxy-target-class="true"/>

现在，无需手动事务调用，一切都可以正常工作。(非常感谢:)

上面的代码正在运行，我可以在Eclipse (mvn：-Dexec.mainClass="maven.springhibernateh2.basic.CRUDTest"). -Dexec.mainClass=“maven.springhibernateh2.basic.CRUDTest”).)中运行它。不幸的是，我无法构建一个可执行的jar来运行它。请看：problem creating an executable jar with maven using spring 5 and hibernate 5 => BeanDefinitionParsingException，我想pom.xml有个问题。如果有任何建议，我将非常高兴。

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/61701466

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