Spring+Jersey+JPA+Hibernate+MySQL整合

package com.spring.jersy.jpa.hibernate.test; import java.util.Iterator; import java.util.List; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; import com.spring.jersy.jpa.hibernate.model.Country; public class JpaTest { private static EntityManagerFactory entityFactory = Persistence .createEntityManagerFactory("springjersyjpa"); public static void main(String agrs[]) { queryProvinceInnerJoinCountry(); } /** * 内连接多表关联查询 */ public static void queryProvinceInnerJoinCountry() { EntityManager em = entityFactory.createEntityManager(); // JPA中JPQL查询，必须为每个table定义别名 //字段名要和实体类中属性相对应 String jql = "select p.proName,c.cname from Province p inner join p.country c "; Query query = em.createQuery(jql); List<Object> list = query.getResultList(); for (Iterator iterator = list.iterator(); iterator.hasNext();) { Object[] obj = (Object[]) iterator.next(); System.out.println(obj[0]+" "+obj[1]); } em.close(); entityFactory.close(); } /** * 查询所有国家 */ public static void findCountryAll() { EntityManager em = entityFactory.createEntityManager(); // JPA中JPQL查询，必须为每个table定义别名 //字段名要和实体类中属性相对应 Query query = em.createQuery("select c.cId, c.cname from Country c "); List<Object> list = query.getResultList(); for (Iterator iterator = list.iterator(); iterator.hasNext();) { Object[] obj = (Object[]) iterator.next(); System.out.println(obj[1]); } em.close(); entityFactory.close(); } /** * 根据国家编号查询国家名称 * * @param id */ public static void queryCountryBycId(Integer id) { EntityManager em = entityFactory.createEntityManager(); // JPA中JPQL查询，必须为每个table定义别名 //字段名要和实体类中属性相对应 Query query = em .createQuery("select c.cname from Country c where c.cId = :id", String.class); String name = (String) query.setParameter("id", id).getSingleResult(); System.out.println(name); em.close(); entityFactory.close(); } /** * 修改信息 */ public static void updateCountry() { EntityManager em = entityFactory.createEntityManager(); //打开事务 em.getTransaction().begin(); Country country = em.find(Country.class, 2); country.setCname("英国"); em.persist(country); //事务提交 em.getTransaction().commit(); em.close(); entityFactory.close(); } /** * 添加信息 */ public static void saveCountry() { EntityManager em = entityFactory.createEntityManager(); em.getTransaction().begin(); Country country = new Country(); country.setCname("中国"); em.persist(country); em.getTransaction().commit(); em.close(); entityFactory.close(); } }