Jsp+JavaBean+servlet购物车

package ch15.JavaBean; import java.sql.ResultSet; import java.sql.SQLException; import java.util.Vector; import ch15.JavaBean.DB_Conn; import ch15.JavaBean.Goods; public class DB_goods { DB_Conn db_conn = new DB_Conn(); // 列出网上商城中所有的商品 public Vector list_goods() { db_conn.ConnectDB(); ResultSet rs = null; try { String sql = "select * from goods"; sql = new String(sql.getBytes("ISO8859-1"), "GB2312"); rs = db_conn.sm.executeQuery(sql); Goods goods = null; Vector vector = new Vector(); // ResultSet指针最初位于第一行之前，调用next方法使下一行成为当前行 while (rs.next()) { goods = new Goods(); goods.setGoods_id(rs.getInt("goods_id")); goods.setGoods_name(rs.getString("goods_name")); goods.setTypeid(rs.getInt("typeid")); goods.setGoods_price(rs.getFloat("goods_price")); goods.setGoods_discount(rs.getFloat("Goods_discount")); goods.setGoods_desc(rs.getString("goods_desc")); goods.setSupplier(rs.getString("supplier")); goods.setQty(rs.getInt("qty")); goods.setIspreferred(rs.getInt("ispreferred")); goods.setGoods_pic(rs.getString("Goods_pic")); // 向Vector矢量中添加对象goods vector.addElement(goods); } return vector; } catch (SQLException SqlE) { SqlE.printStackTrace(); return null; } catch (Exception E) { E.printStackTrace(); return null; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } // 对上述函数进行重载，为了实现通过id获取商品的信息 public Vector list_goods(int id)// 列出网上商城中所有的商品 { db_conn.ConnectDB(); ResultSet rs = null; try { String sql = "select * from goods where Goods_id=" + id; sql = new String(sql.getBytes("ISO8859-1"), "GB2312"); rs = db_conn.sm.executeQuery(sql); Goods goods = null; Vector vector = new Vector(); while (rs.next()) { goods = new Goods(); goods.setGoods_id(rs.getInt("Goods_id")); goods.setGoods_name(rs.getString("Goods_name")); goods.setTypeid(rs.getInt("typeid")); goods.setGoods_price(rs.getFloat("Goods_price")); goods.setGoods_discount(rs.getFloat("Goods_discount")); goods.setGoods_desc(rs.getString("Goods_desc")); goods.setSupplier(rs.getString("supplier")); goods.setQty(rs.getInt("qty")); goods.setIspreferred(rs.getInt("ispreferred")); goods.setGoods_pic(rs.getString("Goods_pic")); vector.addElement(goods); } return vector; } catch (SQLException SqlE) { SqlE.printStackTrace(); return null; } catch (Exception E) { E.printStackTrace(); return null; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } public String getStr(String s) { String str = s; try { byte b[] = str.getBytes("ISO-8859-1"); str = new String(b); return str; } catch (Exception e) { return null; } } // 检索出网上商城中商品编号为Goods_id的商品 public Goods listgoods(String Goods_id) { db_conn.ConnectDB(); ResultSet rs = null; try { String sql = "select * from goods where Goods_id=" + Goods_id; sql = new String(sql.getBytes("ISO8859-1"), "GB2312"); rs = db_conn.sm.executeQuery(sql); Goods goods = null; if (rs.next()) { goods = new Goods(); goods.setGoods_id(rs.getInt("Goods_id")); goods.setGoods_name(rs.getString("Goods_name")); goods.setTypeid(rs.getInt("typeid")); goods.setGoods_price(rs.getFloat("Goods_price")); goods.setGoods_discount(rs.getFloat("Goods_discount")); goods.setGoods_desc(rs.getString("Goods_desc")); goods.setSupplier(rs.getString("supplier")); goods.setQty(rs.getInt("qty")); goods.setIspreferred(rs.getInt("ispreferred")); goods.setGoods_pic(rs.getString("Goods_pic")); } return goods; } catch (SQLException SqlE) { SqlE.printStackTrace(); return null; } catch (Exception E) { E.printStackTrace(); return null; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } public Vector list_goods(String key)// 列出网上商城中所有的商品 { db_conn.ConnectDB(); ResultSet rs = null; try { // String new_key=getStr(key); String sql = "select * from goods where Goods_name like " + "'" + "%" + key + "%" + "'"; rs = db_conn.sm.executeQuery(sql); Goods goods = null; Vector vector = new Vector(); while (rs.next()) { goods = new Goods(); goods.setGoods_id(rs.getInt("Goods_id")); goods.setGoods_name(rs.getString("Goods_name")); goods.setTypeid(rs.getInt("typeid")); goods.setGoods_price(rs.getFloat("Goods_price")); goods.setGoods_discount(rs.getFloat("Goods_discount")); goods.setGoods_desc(rs.getString("Goods_desc")); goods.setSupplier(rs.getString("supplier")); goods.setQty(rs.getInt("qty")); goods.setIspreferred(rs.getInt("ispreferred")); goods.setGoods_pic(rs.getString("Goods_pic")); vector.addElement(goods); } return vector; } catch (SQLException SqlE) { SqlE.printStackTrace(); return null; } catch (Exception E) { E.printStackTrace(); return null; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } // 返回网上商城中商品种类数量 public int goods_count() { db_conn.ConnectDB(); ResultSet rs = null; try { String sql = "select * from goods"; sql = new String(sql.getBytes("ISO8859-1"), "GB2312"); rs = db_conn.sm.executeQuery(sql); int i = 0; // 如果next方法返回true，说明ResultSet指针移至下一行时依然有元素存在，则 // 使得变量i的值加1 while (rs.next()) { i++; } return i; } catch (SQLException SqlE) { SqlE.printStackTrace(); return -1; } catch (Exception E) { E.printStackTrace(); return -2; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } // 修改商品信息 public int goods_update(Goods goods) { db_conn.ConnectDB(); try { String sql = "update goods set Goods_id=" + goods.getGoods_id() + ",Goods_name='" + goods.getGoods_name() + "',typeid=" + goods.getTypeid() + ",Goods_price=" + goods.getGoods_price() + ",Goods_discount=" + goods.getGoods_discount() + ",Goods_desc='" + goods.getGoods_desc() + "',supplier='" + goods.getSupplier() + "',qty=" + goods.getQty() + ",ispreferred=" + goods.getIspreferred() + ",Goods_pic='" + goods.getGoods_pic() + "' where Goods_id=" + goods.getGoods_id(); sql = new String(sql.getBytes("ISO8859-1"), "GB2312"); System.out.println(sql); int i = db_conn.sm.executeUpdate(sql); return i; } catch (SQLException SqlE) { SqlE.printStackTrace(); return -1; } catch (Exception E) { E.printStackTrace(); return -2; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } // 插入商品信息 public int goods_insert(Goods goods) { db_conn.ConnectDB(); try { String sql = "insert into goods (Goods_name,typeid," + "Goods_price,Goods_discount,Goods_desc,supplier," + "qty,ispreferred,Goods_pic) values(" + "'" + goods.getGoods_name() + "'" + "," + goods.getTypeid() + "," + goods.getGoods_price() + "," + goods.getGoods_discount() + "," + "'" + goods.getGoods_desc() + "'" + "," + "'" + goods.getSupplier() + "'" + "," + goods.getQty() + "," + goods.getIspreferred() + "," + "'" + goods.getGoods_pic() + "'" + ")"; sql = new String(sql.getBytes("ISO8859-1"), "GB2312"); int i = db_conn.sm.executeUpdate(sql); return i; } catch (SQLException SqlE) { SqlE.printStackTrace(); return -1; } catch (Exception E) { E.printStackTrace(); return -2; } finally { // 关闭连接，释放数据库资源： db_conn.CloseDB(); } } // 删除商品信息 public int goods_delete(int Go