Spring Data JPA 取得EntityManager實例

Spring Data JPA取得EntityManger實例的作法如下。

在Spring component使用@PersistenceContext即可注入persistence context管理的EntityManger的實例。

DemoDao

import org.springframework.stereotype.Repository;

import javax.persistence.EntityManager;

@Repository
public class DemoDao {

    @PersistenceContext
    private EntityManager em; // spring will inject EntityManager instance

    ...
}

• How to access entity manager with spring boot and spring data
• Guide to the Hibernate EntityManager
• Hibernate JPA Entity 生命週期 (JPA Entity Lifecycle)