我正在使用Hibernate和JPA进行一个小项目。在尝试获取一个类型化的查询时,有些问题。
java.lang.AbstractMethodError: org.hibernate.ejb.EntityManagerImpl.createQuery(Ljava/lang/String;Ljava/lang/Class;)Ljavax/persistence/TypedQuery
抛出的异常来自org.hibernate.ejb.EntityManagerImpl,该类位于hibernate-entitymanager-3.3.2.GA.jar。
以上异常的抛出是不正常的:
public Account read(Account entity) {
EntityManager em = ManagedEntityManagerFactory.getEntityManager();
String jpql = JPQLGenerator.readAccount();
TypedQuery<Account> typedQuery =
em.createQuery(jpql, Account.class);
typedQuery.setParameter("accountId", entity.getAccountId());
return typedQuery.getSingleResult();
}
这样是可以的,但是:
public Account read(Account entity) {
EntityManager em = ManagedEntityManagerFactory.getEntityManager();
String jpql = JPQLGenerator.readAccount();
Query query =
em.createQuery(jpql);
query.setParameter("accountId", entity.getAccountId());
Account account = null;
Object obj = query.getSingleResult();
if(obj instanceof Account) {
account = (Account)obj;
}
return account;
}