在春季3,无法在JPA中坚持实体

Question

尽管findAll在这里工作,但我无法在JPA中持久化实体.这是JpaDAO

package aop.web.teacher.dao;

import java.lang.reflect.ParameterizedType;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceException;
import javax.persistence.Query;

import org.apache.log4j.Logger;
import org.springframework.orm.jpa.JpaCallback;
import org.springframework.orm.jpa.support.JpaDaoSupport;
import org.springframework.stereotype.Repository;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;


public abstract class JpaDAO extends JpaDaoSupport {
 protected Class entityClass;

 private static Logger log = Logger.getLogger(JpaDAO.class);

 @SuppressWarnings("unchecked")
 public JpaDAO() {
  ParameterizedType genericSuperclass = (ParameterizedType) getClass()
    .getGenericSuperclass();
  this.entityClass = (Class) genericSuperclass
    .getActualTypeArguments()[1];
 }

 @Transactional(readOnly = false, propagation = Propagation.REQUIRES_NEW)
 public void persist(E entity) {
  getJpaTemplate().persist(entity);
 }

 @Transactional
 public void remove(E entity) {
  getJpaTemplate().remove(entity);
 }

 @Transactional
 public E merge(E entity) {
  return getJpaTemplate().merge(entity);
 }

 @Transactional
 public void refresh(E entity) {
  getJpaTemplate().refresh(entity);
 }

 @Transactional
 public E findById(K id) {
  return getJpaTemplate().find(entityClass, id);
 }

 @Transactional
 public E flush(E entity) {
  getJpaTemplate().flush();
  return entity;
 }

 @SuppressWarnings("unchecked")
 @Transactional
 public List findAll() {
  Object res = getJpaTemplate().execute(new JpaCallback() {

   public Object doInJpa(EntityManager em) throws PersistenceException {
    Query q = em.createQuery("SELECT h FROM "
      + entityClass.getName() + " h");
    return q.getResultList();
   }

  });

  return (List) res;
 }

 @SuppressWarnings("unchecked")
 @Transactional
 public Integer removeAll() {
  return (Integer) getJpaTemplate().execute(new JpaCallback() {

   public Object doInJpa(EntityManager em) throws PersistenceException {
    Query q = em.createQuery("DELETE FROM " + entityClass.getName()
      + " h");
    return q.executeUpdate();
   }

  });
 }

}

这是TestDao类

package aop.web.teacher.dao;

import java.util.Date;
import java.util.List;

import javax.annotation.PostConstruct;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.stereotype.Service;



import aop.web.teacher.rmodels.Teachermaster;

@Service
@Repository
public class TestDaoImpl extends JpaDAO implements TestDao {

 @Autowired
 EntityManagerFactory entityManagerFactory;

 @PersistenceContext
 private EntityManager em;

 @PostConstruct
 public void init() {
  super.setEntityManagerFactory(entityManagerFactory);
 }

 public int saveTeacher() {
  List teacherList = findAll();
  Teachermaster m1 = teacherList.get(0);
  logger.info("Found " + m1.getId() + " and " + m1.getRace());
  m1.setRace(m1.getRace() + "::" + System.currentTimeMillis());
  logger.info("New " + m1.getId() + " and " + m1.getRace());
  persist(m1);
  return 0;
 }

}

这是spring context xml

http://pastebin.com/pKqzW9h1

这里findAll有效,但是当我们对Teachermaster的属性进行更改时,持久化或合并似乎不会保存实体...如果我们刷新它,我们会得到异常

javax.persistence.TransactionRequiredException: no transaction is in progress

请指教

Answer 1

Spring使用基于代理的AOP,因此当从同一个类调用方法时,不应用方面(包括事务方面).

一般来说

• @Transactional 注释通常应放在服务方法上而不是DAO方法上
• 您saveTeacher()看起来像一个服务方法,最好将它放在单独的服务类中并注释为@Transactional
• 您不需要persist()in saveTeacher()- 应该自动保存对持久对象所做的更改
• 注意动态代理与目标类代理的区别(关于TestDao) - 请参阅下面的链接

也可以看看:

• 7.6.1了解AOP代理
• 10.5.1了解Spring Framework的声明式事务实现