購物網站12：文件上傳Service---根據ID獲取文件的真實路徑

@Service @Transactional
public class UploadFileServiceBean extends DaoSupport<UploadFile> implements UploadFileService {

 @SuppressWarnings("unchecked")
 public List<String> getFilepath(Integer[] ids){
  if(ids!=null && ids.length>0){
   StringBuffer jpql = new StringBuffer();
   for(int i=0; i<ids.length;i++){
    jpql.append('?').append((i+1)).append(',');
   }
   jpql.deleteCharAt(jpql.length()-1);
   Query query = em.createQuery("select o.filepath from UploadFile o where o.id in("+ jpql.toString()+ ")");
   for(int i=0; i<ids.length;i++){
    query.setParameter(i+1, ids[i]);
   }
   return query.getResultList();
  }
  return null;
 }
}