@Repository @Transactional(readOnly = true)  class AccountServiceImpl implements AccountService {    @PersistenceContext   private EntityManager em;    @Override   @Transactional   public Account save(Account account) {      if (account.getId() == null) {        em.persist(account);        return account;      } else {        return em.merge(account);      }    }    @Override   public List<Account> findByCustomer(Customer customer) {      TypedQuery query = em.createQuery("select a from Account a where a.customer = ?1", Account.class);      query.setParameter(1, customer);      return query.getResultList();    }      @Override   public List<Customer> findAll(int page, int pageSize) {      TypedQuery query = em.createQuery("select c from Customer c", Customer.class);      query.setFirstResult(page * pageSize);      query.setMaxResults(pageSize);      return query.getResultList();    }     }    

原文出处：Netkiller 系列 手札

本文作者：陈景峯 转载请与作者联系，同时请务必标明文章原始出处和作者信息及本声明。