基于Java的在线购物系统的设计与实现

package beans; import java.sql.*; public class connDB{ Connection conn=null; Statement stmt=null; ResultSet rs=null; public connDB(){ try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); }catch(java.lang.ClassNotFoundException e){ System.err.println(e.getMessage()); } } /*************************************************** *method name: executeQuery() *功能:执行查询操作 *return value: ResultSet *2007-03-05 ****************************************************/ public ResultSet executeQuery(String sql){ try{ conn=DriverManager.getConnection("jdbc:odbc:db_bookmanage"); stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); rs=stmt.executeQuery(sql); }catch(SQLException ex){ System.err.println(ex.getMessage()); } return rs; } /*************************************************** *method name: executeUpdate() *功能:执行更新操作 *return value: int *2007-03-05 ****************************************************/ public int executeUpdate(String sql){ int result=0; try{ conn=DriverManager.getConnection("jdbc:odbc:db_bookmanage"); stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); result=stmt.executeUpdate(sql); }catch(SQLException ex){ result=0; } return result; } /*************************************************** *method name:executeUpdate_id() *功能:执行更新操作并返回自动编号的值 *return value: int *2007-03-05 ****************************************************/ public int executeUpdate_id(String sql) { int result = 0; try{ conn=DriverManager.getConnection("jdbc:odbc:db_bookmanage"); stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); result = stmt.executeUpdate(sql); String ID = "select @@IDENTITY as id"; rs = stmt.executeQuery(ID); if (rs.next()) { int autoID = rs.getInt("id"); result = autoID; } } catch (SQLException ex) { result = 0; } return result; } /*************************************************** *method name: close() *功能:关闭数据库链接 *return value: void *2007-03-05 ****************************************************/ public void close() { try { if (rs != null) { rs.close(); //关闭ResultSet结果集 } } catch (Exception e) { e.printStackTrace(System.err); } try { if (stmt != null) { stmt.close(); //关闭Statement } } catch (Exception e) { e.printStackTrace(System.err); } try { if (conn != null) { conn.close(); //关闭Connection } } catch (Exception e) { e.printStackTrace(System.err); } } }