PetStore中EJB的设计模式 ∥获得产品信息 public Page getProducts(String categorylD, int start, int count, Locale D)i ∥调周用DAO,实现业务逻辑 return dao. get Products(categorylD, start, count, I) catchCatalog Exception se)( throw new EJBException(se. getMessageo) 2.1.4.3 CatalogDAO public interface CatalogDAO ∥声明能力 public Page getProducts( String categorylD, int start, int count, Locale D) throws CatalogDAOSys Exception 2.1.4.4 Catalog DAOImpl DAOpublic class Catalog DAOlmpl implements CatalogDAO public Page get Products( String categoryID, int start, int count, Locale D)i { c=getDataSource(). getConnectiono ps=c prepare Statement("select a productid, name, descn oduct details b +"and a catid = +"order by name ResultSet TYPE SCROLL INSENSITIVE, ResultSet CONCUR READ ONLY ps setString(l, 1. toString(); ps setString(2, category); rs=ps execute QueryO ∥读取数据库 catch(SQLException se)PetStore 中 EJB 的设计模式 9/9 //获得产品信息 public Page getProducts(String categoryID, int start, int count, Locale l) { try { //调用 DAO,实现业务逻辑 return dao.getProducts(categoryID, start, count, l); } catch (CatalogDAOSysException se) { throw new EJBException(se.getMessage()); } } 2.1.4.3 CatalogDAO public interface CatalogDAO { //声明能力 public Page getProducts(String categoryID, int start, int count, Locale l) throws CatalogDAOSysException; } 2.1.4.4 CatalogDAOImpl DAOpublic class CatalogDAOImpl implements CatalogDAO { public Page getProducts(String categoryID, int start, int count, Locale l){ try { c = getDataSource().getConnection(); ps = c.prepareStatement("select a.productid, name, descn " + "from (product a join " + "product_details b on " + "a.productid=b.productid) " + "where locale = ? " + "and a.catid = ? " + "order by name", ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); ps.setString(1, l.toString()); ps.setString(2, categoryID); rs = ps.executeQuery(); //读取数据库 rs.close(); ps.close(); } catch (SQLException se) {