配置能够@在Seam 3中注入EntityManager [英] Configuration to be able to @Inject EntityManager in Seam 3

问题描述

在我的项目中，我使用 Seam 3 ，并且我注意到 EntityManager c> @Inject 注释。我确定有一些配置，以确保 EnityManager 知道使用 PersistenceUnit 。例如， EJB 可以输入：

In my project I use Seam 3 and I am having issues injecting the EntityManager with the @Inject annotation. I am pretty sure there is some kind of configuration to make sure the EnityManager knows which PersistenceUnit to use. For example with EJB you can type:

@PersistenceContext(unitName="MY_PERSISTENCE_UNIT_NAME")
private EntityManager eManager;

哪些持久化单元配置在 persistence.xml 文件。这是我的伪配置：

which persistence unit is configured in the persistence.xml file. Here is my pseudo configuration:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

    <persistence-unit name="MY_PERSISTENCE_UNIT_NAME" transaction-type="JTA">

        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <jta-data-source>java:jboss/TimeReportDS</jta-data-source>
        <mapping-file>META-INF/orm.xml</mapping-file> 

        <class>....</class>
        <class>....</class>
        <class>....</class>

        <properties>

            <property name="jboss.entity.manager.factory.jndi.name"
                value="java:/modelEntityManagerFactory" />

            <!-- PostgreSQL Configuration File -->
            <property name="hibernate.connection.driver_class" value="org.postgresql.Driver" />
            <property name="hibernate.connection.password" value="password" />
            <property name="hibernate.connection.url" value="jdbc:postgresql://192.168.2.125:5432/t_report" />
            <property name="hibernate.connection.username" value="username" />

            <!-- Specifying DB Driver, providing hibernate cfg lookup
                 and providing transaction manager configuration -->
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
            <property name="hibernate.transaction.factory_class" value="org.hibernate.transaction.JTATransactionFactory"/>
            <property name="hibernate.transaction.manager_lookup_class"
                value="org.hibernate.transaction.JBossTransactionManagerLookup" />
            <property name="hibernate.archive.autodetection" value="class" />

            <!-- Useful configuration during development - developer can see structured SQL queries -->
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="false" />

        </properties>
    </persistence-unit>
</persistence>  

我已经读了一些关于Seam 2的文章，但是配置在 components.xml 文件中添加：

I have read some articles about Seam 2 but there the configuration is made in components.xml file by adding the:

<persistence:managed-persistence-context
        name="entityManager" auto-create="true" persistence-unit-jndi-name="java:/modelEntityManagerFactory" />

< Seam 2中的下一步是添加：

inside the <components> tag. The next step in Seam 2 is to add the:

<property name="jboss.entity.manager.factory.jndi.name"
                value="java:/modelEntityManagerFactory" />

>

in the persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence ...>
    <persistence-unit name="MY_PERSISTENCE_UNIT_NAME" ...>
        ...
        <properties>
            ...

            <property name="jboss.entity.manager.factory.jndi.name"
                value="java:/modelEntityManagerFactory" />

        </properties>
    </persistence-unit>
</persistence>

但是它在Seam 3中没有文件 components.xml 。此外，在 @Inject 注释中没有指定持久性单元的属性 unitName 。

but it seam that in Seam 3 there is no file components.xml. Also there is no attribute unitName in @Inject annotation to specify the persistence unit.

因此，请帮助我配置我的项目，以便可以使用 @Inject 和 EntityManager ，如网上的很多示例所示。

So please help me to configure my project so I can use the @Inject with EntityManager as shown in many examples on the net.

我使用 Postgres 数据库和 JBoss AS 7 。

编辑：添加示例。我不在 Entity 类中使用 EntityManager 。

Adding an example. I don't use the EntityManager in an Entity class.

@Named("validateReportAction")
@SessionScoped
public class ValidateReportAction extends ReportAction implements Serializable {

    private static final long serialVersionUID = -2456544897212149335L;

    @Inject
    private EntityManager em;
...
}  

@Inject 我从 Eclipse 获得警告没有bean可以注入到注入点[JSR-299§5.2 .1]

如果我在一些bean上使用 @Inject 标记为实体 @Inject 可以正常工作。

If I use the @Inject on some beans that are marked as Entity the @Inject works fine.

推荐答案

您可以在CDI bean上使用@PersistenceContext。它不一定是一个EJB。

You can use @PersistenceContext on a CDI bean. It doesn't have to be an EJB.

如果由于某种原因你想使用@Inject，你必须做更多的工作。 @Inject不知道EntityManager;它只能注入其他托管bean。幸运的是，有一个简单的解决方法 - 使用一个作为一个简单的蹦床的生产者方法。

If for some reason you want to use @Inject, you have to do more work. @Inject doesn't know about the EntityManager; it can only inject other managed beans. Happily, there is a simple workaround - use a producer method that acts as a simple trampoline.

@ApplicationScoped
public class EntityManagerProducer {

    @PersistenceContext
    private EntityManager entityManager;

    @Produces
    @RequestScoped
    public EntityManager getEntityManager {
        return entityManager;
    }

    public void closeEntityManager(@Disposes EntityManager em) {
        if (em != null && em.getTransaction().isActive()) {
            em.getTransaction().rollback();
        }
        if (em != null && em.isOpen()) {
            em.close();
        }
    }

}

现在使用@Inject注入EntityManager。注入的EntityManager将是RequestScoped，而EntityManagerProducer是ApplicationScoped。此外，entityManager必须关闭。

You can now use @Inject to inject the EntityManager. The injected EntityManager will be RequestScoped, while the EntityManagerProducer is ApplicationScoped. Furthermore, the entityManager must be closed.

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