使用JPA / JTA / JBOSS / CDI无法持久保存对象

Question

请帮助我了解为什么以下代码无法持久化对象。 它引发javax.persistence.TransactionRequiredException：JBAS011469：需要事务才能执行此操作（使用事务或扩展的持久性上下文）

public class OrganizationRepositoryImpl implements OrganizationRepository {

    @PersistenceContext(unitName="usermanagement",type=PersistenceContextType.TRANSACTION)
    private EntityManager em;

    public void save(Organization organization) {
        try {
            em.persist(organization);
        }catch(Exception e) {
            e.printStackTrace();

        }
    }    
}

但是，如果我使用@Stateless批注（现在为ejb）对类进行批注，则对象将开始保留

@Stateless    
public class OrganizationRepositoryImpl implements OrganizationRepository {

            @PersistenceContext(unitName="usermanagement",type=PersistenceContextType.TRANSACTION)
            private EntityManager em;

            public void save(Organization organization) {
                try {
                    em.persist(organization);
                }catch(Exception e) {
                    e.printStackTrace();

                }
            }    
        }

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"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
        version="2.1">
    <persistence-unit name="usermanagement" transaction-type="JTA">
        <jta-data-source>java:jboss/datasources/MysqlXADS</jta-data-source>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <properties>
             <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
             <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
             <property name="hibernate.show_sql" value="true"/>
             <property name="hibernate.format_sql" value="true"/>  
             <property name="use_sql_comments" value="true"/>
             <property name="jboss.entity.manager.factory.jndi.name" value="java:jboss/myEntityManagerFactory" /> 
        </properties>
    </persistence-unit>
</persistence>

服务类调用存储库以将对象持久存储到数据库中

    public class OrganizationServiceImpl implements OrganizationService {

    @Inject
    private OrganizationRepository orgRepo;

    public Response createOrganization(InputStream is) {
        Organization org = null;
        org = readStream(is);
        orgRepo.save(org);
        return Response.created(URI.create("/organizations/" + org.getId()))
                .build();
    }

    private Organization readStream(InputStream is) {
        JAXBContext context;
        Organization org = null;
        try {
            context = JAXBContext.newInstance(Organization.class);
            Unmarshaller um = context.createUnmarshaller();
            org = (Organization) um.unmarshal(is);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
        return org;
    }
}  

Answer 1

当您将bean声明为@Stateless ，默认情况下该bean中的方法是事务性的。 事务方法在完全执行时会提交持久状态。

当您没有用@Stateless方法注释的类时，默认情况下不会进行事务处理，因此您会遇到上述异常。

Answer 2

我对EJB不太熟悉，但是我相信问题在于，如果没有@Stateless批注，则bean不是EJB，因此不会自动管理事务。 如果需要有状态，请使用@Stateful批注创建有状态EJB。 如果您不想使用EJB，则必须像这样使用EntityManager手动管理事务。

tx = em.getTransaction();
tx.begin();

// do some work
...

tx.commit();