JSPMVC的经典案例

package com.svse.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import com.svse.DBC.DBConnection; import com.svse.bean.Spbean; public class Spdao { DBConnection b = new DBConnection(); Connection conn = null; PreparedStatement pre = null; ResultSet rs = null; public Spdao() { conn = b.getConnection(); } /** *****************增加商品********************* */ public void addsp(Spbean bean) { String sql = "insert into t_sp values(?,?)"; try { pre = conn.prepareStatement(sql); pre.setString(1, bean.getS_name()); pre.setDouble(2, bean.getS_price()); pre.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (pre != null) { pre.close(); } } catch (Exception e) { e.printStackTrace(); } } } /** *****************查询所有商品**************** */ public List getallsp() { List ar = new ArrayList(); String sql = "select * from t_sp "; try { pre = conn.prepareStatement(sql); rs = pre.executeQuery(); while (rs.next()) { Spbean bean = new Spbean(); bean.setS_id(rs.getInt("s_id")); bean.setS_name(rs.getString("s_name")); bean.setS_price(rs.getDouble("s_price")); ar.add(bean); } } catch (Exception e) { e.printStackTrace(); } finally { try { if (rs != null) { rs.close(); } if (pre != null) { pre.close(); } } catch (Exception e) { e.printStackTrace(); } } return ar; } /** *****************查询单个商品**************** */ public Spbean getonlysp(int s_id) { Spbean bean = new Spbean(); String sql = "select * from t_sp where s_id=?"; try { pre = conn.prepareStatement(sql); pre.setInt(1, s_id); rs = pre.executeQuery(); while (rs.next()) { bean.setS_id(rs.getInt("s_id")); bean.setS_name(rs.getString("s_name")); bean.setS_price(rs.getDouble("s_price")); } } catch (Exception e) { e.printStackTrace(); } finally { try { if (rs != null) { rs.close(); } if (pre != null) { pre.close(); } } catch (Exception e) { e.printStackTrace(); } } return bean; } /** *****************修改商品******************* */ public void upsp(Spbean bean) { String sql = "update t_sp set s_name=?,s_price=? where s_id=?"; try { pre = conn.prepareStatement(sql); pre.setString(1, bean.getS_name()); pre.setDouble(2, bean.getS_price()); pre.setInt(3, bean.getS_id()); pre.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (pre != null) { pre.close(); } } catch (Exception e) { e.printStackTrace(); } } } /** *****************删除商品******************* */ public void delsp(int s_id) { String sql = "delete from t_sp where s_id=?"; try { pre = conn.prepareStatement(sql); pre.setInt(1, s_id); pre.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (pre != null) { pre.close(); } } catch (Exception e) { e.printStackTrace(); } } } }