Java和Spring。事务注释@Transactional

Question

我想从DAO类中删除begin和commit事务，并且我需要使用事务注释。应该怎么做？ 现在，例外是组织。冬眠HibernateException:没有活动事务，createQuery无效

当然可以。爪哇

public interface CoursesDAO {

public Course createCourse(Course course);

public Course findCourseById(Integer key);

public Course updateCourse(Course course);

public void deleteCourse(Course course);

public List<Course> getAllCourses();

public List<Course> getAllCoursesByCategory(String category);

public List<Course> getAllCoursesWhichNoProposal( );

}

课程DAOImpl。爪哇

@Repository
public class CoursesDAOImpl implements CoursesDAO {

 @Autowired
 private SessionFactory sessionFactory;

public Course createCourse(Course course) {

     Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    Integer id = (Integer) sessionFactory.getCurrentSession().save(course);
    course.setId(id);
    //session.getTransaction().commit();

    return course;
};

public Course findCourseById(Integer id) {

    Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    Course course = (Course) session.get(Course.class, id);
    //session.getTransaction().commit();

    return course;
}


public Course updateCourse(Course course) {

    Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    session.merge(course);
    //session.getTransaction().commit();

    return course;
};

public void deleteCourse(Course course) {

    Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    session.delete(course);
    //session.getTransaction().commit();    



};

public List<Course> getAllCourses() {

    Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    List listCourses = session.createQuery("from Course").list();
    //session.getTransaction().commit();
    return listCourses;
}



public List<Course> getAllCoursesByCategory(String category) {

    Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    List listCoursesByCategory = session.createQuery("from Course c where c.category='"+category+"'").list();
    //session.getTransaction().commit();

    return listCoursesByCategory;
}


public List<Course> getAllCoursesWhichNoProposal( ) {

    Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    List listCoursesNoProposal = session.createQuery("from Course c where c.state not like 'Proposal' and c.state not like 'Rejected'").list();
    //session.getTransaction().commit();

    return listCoursesNoProposal;
}

}

课程服务。爪哇

public interface CourseService {

public Course findCourseById(Integer id);

public Course updateCourse(Course course);

public Course createCourse(Course course);

public void deleteCourse(Course course);

public List<Course> getAllCourses();

public List<Course> getAllCoursesByCategory(String category);

public List<Course> getAllCoursesWhichNoProposal( );

}

CourseServiceImpl。爪哇

@Service
public class CourseServiceImpl implements CourseService {
@Autowired
private CoursesDAO coursesDAOImpl;


@Transactional
public Course findCourseById(Integer id) {

    Course course = coursesDAOImpl.findCourseById(id);

    return course;
}
@Transactional
public Course updateCourse(Course course) {

    // Course.openCurrentSessionwithTransaction();

    course = coursesDAOImpl.updateCourse(course);

    // Course.closeCurrentSessionwithTransaction();
    return course;
}
@Transactional
public Course createCourse(Course course) {

      //Course.openCurrentSessionwithTransaction();

    course = coursesDAOImpl.createCourse(course);

      //Course.closeCurrentSessionwithTransaction();
    return course;
}
@Transactional
public List<Course> getAllCourses() {

    // Course.openCurrentSessionwithTransaction();

    List<Course> listCourses = coursesDAOImpl.getAllCourses();

    // Course.closeCurrentSessionwithTransaction();
    return listCourses;
}
@Transactional
public List<Course> getAllCoursesByCategory(String category) {

    // Course.openCurrentSessionwithTransaction();

    List<Course> listCoursesByCategory = coursesDAOImpl
            .getAllCoursesByCategory(category);

    // Course.closeCurrentSessionwithTransaction();
    return listCoursesByCategory;
}

@Transactional
public List<Course> getAllCoursesWhichNoProposal( ) {

    // Course.openCurrentSessionwithTransaction();

    List<Course> listCoursesNoProposal = coursesDAOImpl
            .getAllCoursesWhichNoProposal( );

    // Course.closeCurrentSessionwithTransaction();
    return listCoursesNoProposal;
}
@Transactional
public void deleteCourse(Course course) {
    coursesDAOImpl.deleteCourse(course);

};

应用程序上下文。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:context="http://www.springframework.org/schema/context"
xmlns:security="http://www.springframework.org/schema/security"
xmlns:mvc="http://www.springframework.org/schema/mvc"   xmlns:p="http://www.springframework.org/schema/p"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
    http://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">

<mvc:annotation-driven />

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
    destroy-method="close"
    p:driverClassName="org.h2.Driver"
    p:url="jdbc:h2:tcp://localhost:9092/~/QWE;INIT=create schema if not exists QWE\;"
    p:username="sa"
    p:password="" />

<bean id="sessionFactory"
    class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="hibernateProperties">   
    <props>
<prop key="hibernate.dialect">org.hibernate.dialect.H2Dialect</prop> 
<prop key="hibernate.show_sql">true</prop> 
<prop key="connection.pool_size">1</prop> 
<prop key="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</prop>
<prop key="hibernate.current_session_context_class">thread</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop> 
<prop key="hibernate.default_schema">QWE</prop>
</props>    
</property> 

<property name="annotatedClasses">
  <list>
    <value>com.epam.edu.jtc.entity.User</value>
    <value>com.epam.edu.jtc.entity.Category</value>
    <value>com.epam.edu.jtc.entity.Course</value>
    <value>com.epam.edu.jtc.entity.UserCourse</value>
    <value>com.epam.edu.jtc.entity.ManagerCourse</value>
     </list>
 </property>
 </bean>        

<!-- FreeMarker Configuration -->
<bean id="freemarkerEmailConfig" class="freemarker.template.Configuration">
<property name="directoryForTemplateLoading" value="WEB-INF/pages/templates" />
<property name="objectWrapper">
    <bean class="freemarker.template.DefaultObjectWrapper"/>
</property>

</bean>

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
 <tx:annotation-driven transaction-manager="transactionManager"/>   
 <context:component-scan base-package="com.epam.edu.jtc" />

</beans>

Answer 1

我想这是一个概念上的问题

适当的体系结构应该是拥有一个调用存储库的事务服务。像这样的

@Service
public class CoursesServiceImpl implements CoursesService {

  @Autowired
  private CoursesDAO coursesDAO;

  @Override
  @Transactional
  public void insertCourses(Course courses) {
    coursesDAO.createCourse(courses);
  }

}

然后是您的存储库

@Repository
public class CoursesDAOImpl implements CoursesDAO {

@Autowired
private SessionFactory sessionFactory;

public Course createCourse(Course course) {

   Session session = sessionFactory.getCurrentSession();
    //session.beginTransaction();
    Integer id = (Integer) session.save(course);
    course.setId(id);
    //session.getTransaction().commit();

    return course;
};

Answer 2

在设置了正确的事务管理器之后，只需尝试将@Transactional注释移动到所实现类上的方法

    @Repository
    public class CoursesDAOImpl implements CoursesDAO {

    @Autowired
    private SessionFactory sessionFactory;

    @Transactional 
public Course createCourse(Course course) {

Answer 3

您的配置中有两个缺陷

首先，在使用@Transactional时，您还必须通过在应用程序上下文文件中包含<tx:annotation-driven />标记来明确配置。如果不是的话，你的@Transactional将什么也不做

简单添加<tx:annotation-driven transaction-manager="txManager/>，因为您将其命名为不同于transactionManager（默认名称）。当然，您还必须将正确的xsd添加到头中，以使tx名称空间可用

xmlns:tx="http://www.springframework.org/schema/tx"

并将其添加到schemaLocation属性中

http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

其次，您已经在hibernate配置中配置了hibernate.current_session_context_class属性。这打破了与spring的适当集成，后者将其设置为自定义spring类，但是您的设置会覆盖此设置。删除此属性

另一个要考虑的是实际事务边界应该是服务层而不是数据访问层。您的服务方法是全有或全无操作，如果您有3个数据库调用，它们都应该参与同一事务。通过设置，您将获得3个单独的事务，例如，在执行多个更新时，这些事务可能会使数据库处于不希望的状态。我建议将@Transactional移动到您的服务层，而不是数据访问层