如何以编程方式将持久性上下文注入不同的数据源 [英] How to inject persistence context to different data source programmatically

问题描述

在标准EJB 3中，当注入实体管理器时，持久性单元(指数据源)被硬编码到注释中:(或XML文件)

In standard EJB 3, when injecting entity manager, persistence unit (which refers to datasource) is hardcoded into annotation: (or alternatively xml file)

@PersistenceContext(unitName = "myunit")
private EntityManager entityManager;

是否可以使用实体管理器，但可以在运行时通过名称选择数据源?

Is there a way to use an entity manager but to select data source by name at runtime?

推荐答案

使用EclipseLink，您可以设置在应用服务器中配置的数据源.

Using EclipseLink, You can set a DataSource configured in your app server.

import org.eclipse.persistence.config.PersistenceUnitProperties;
...


....
Map props = new HashMap();  
props.put(PersistenceUnitProperties.JTA_DATASOURCE, "dataSource");  
EntityManagerFactory  emf = Persistence.createEntityManagerFactory("UNIT_NAME", props);
EntityManager em = emf.createEntityManager();

PU_NAME是指文件persistence.xml
中使用的名称. dataSource将应用服务器中用于jdbc资源的名称称为"jdbc/sample"

PU_NAME refers to the name used in the file persistence.xml
dataSource refers name used in the app server for the jdbc Resource as "jdbc/sample"

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