model层之dao--SqlHelper

贴一下SqlHelper的代码：

 001 /** 

002  * 功能：对数据库的操作的封装 

003  */

004   

005 package cn.zwh.util; 

006   

007 import java.sql.*; 

008 import java.util.*; 

009 import java.io.*; 

010   

011 public class SqlHelper { 

012     //操作数据库必备 

013     private static Connection ct = null; 

014     private static PreparedStatement ps = null; 

015     private static ResultSet rs = null; 

016       

017     //一些常量 

018     private static String url = ""; 

019     private static String username = ""; 

020     private static String password = ""; 

021     private static String driver = ""; 

022       

023     private static Properties pp = null; 

024     //private static FileInputStream fis = null; 

025     private static InputStream is = null; 

026       

027     //静态，只执行一次 

028     static{ 

029         try { 

030             pp = new Properties(); 

031             //默认读取的主目录是在tomcat的主目录的bin目录下； 

032             //fis = new FileInputStream("dbinfo.properties"); 

033             //默认读取的主目录是在src目录下； 

034             is = SqlHelper.class.getClassLoader().getResourceAsStream("dbinfo.properties"); 

035             pp.load(is); 

036             //把一些常量搞定一下 

037             url = pp.getProperty("url"); 

038             username = pp.getProperty("username"); 

039             password = pp.getProperty("password"); 

040             driver = pp.getProperty("driver"); 

041               

042             //加载驱动 

043             Class.forName(driver); 

044         } catch (Exception e) { 

045             e.printStackTrace(); 

046             // TODO: handle exception 

047         }finally{ 

048             //关闭资源 

049 //          if(fis != null){ 

050 //              try { 

051 //                  fis.close(); 

052 //              } catch (IOException e) { 

053 //                  // TODO Auto-generated catch block 

054 //                  e.printStackTrace(); 

055 //              } 

056 //              fis = null; 

057 //          } 

058             if(is != null){ 

059                 try { 

060                     is.close(); 

061                 } catch (IOException e) { 

062                     // TODO Auto-generated catch block 

063                     e.printStackTrace(); 

064                 } 

065                 is = null; 

066             } 

067         } 

068     } 

069       

070     //得到连接 

071     public static Connection getConnection() 

072     { 

073         try { 

074             ct = DriverManager.getConnection(url, username, password); 

075         } catch (Exception e) { 

076             e.printStackTrace(); 

077             // TODO: handle exception 

078         }finally{ 

079             //关闭资源 

080             //由调用者自己关闭 

081         } 

082         return ct; 

083     } 

084       

085     //提供查询 

086     public static ResultSet executeQuery(String sql, String parameters[]) 

087     { 

088         try { 

089             //得到连接 

090             ct = getConnection(); 

091             //执行查询语句 

092             ps = ct.prepareStatement(sql); 

093             if(parameters != null) 

094             { 

095                 for(int i = 0; i<parameters.length;i++) 

096                 { 

097                     ps.setString(i+1, parameters[i]); 

098                 } 

099             } 

100               

101             rs = ps.executeQuery(); 

102         } catch (Exception e) { 

103             e.printStackTrace(); 

104             // TODO: handle exception 

105         }finally{ 

106             //关闭资源 

107             //自己关闭 

108         } 

109         return rs; 

110     } 

111       

112     //提供简单的增，删，改 

113     public static void executeUpdate(String sql, String parameters[]) 

114     { 

115         try { 

116             ct = getConnection(); 

117             ps = ct.prepareStatement(sql); 

118             if(parameters != null) 

119             { 

120                 for(int i = 0; i<parameters.length;i++) 

121                 { 

122                     ps.setString(i+1, parameters[i]); 

123                 } 

124             } 

125             ps.executeUpdate(); 

126         } catch (Exception e) { 

127             e.printStackTrace(); 

128             // TODO: handle exception 

129         }finally{ 

130             //关闭资源 

131         } 

132     } 

133       

134     //提供关闭资源的方法 

135     public static void close(ResultSet rs, PreparedStatement ps, Connection ct) 

136     { 

137         if(rs != null) 

138         { 

139             try { 

140                 rs.close(); 

141             } catch (Exception e) { 

142                 // TODO Auto-generated catch block 

143                 e.printStackTrace(); 

144             } 

145             rs = null; 

146         } 

147           

148         if(ps != null) 

149         { 

150             try { 

151                 ps.close(); 

152             } catch (SQLException e) { 

153                 // TODO Auto-generated catch block 

154                 e.printStackTrace(); 

155             } 

156             ps = null; 

157         } 

158           

159         if(ct != null) 

160         { 

161             try { 

162                 ct.close(); 

163             } catch (SQLException e) { 

164                 // TODO Auto-generated catch block 

165                 e.printStackTrace(); 

166             } 

167             ct = null; 

168         } 

169     } 

170   

171     //得到这里面的ct, ps, rs 

172     public static Connection getCt() { 

173         return ct; 

174     } 

175   

176     public static void setCt(Connection ct) { 

177         SqlHelper.ct = ct; 

178     } 

179   

180     public static PreparedStatement getPs() { 

181         return ps; 

182     } 

183   

184     public static void setPs(PreparedStatement ps) { 

185         SqlHelper.ps = ps; 

186     } 

187   

188     public static ResultSet getRs() { 

189         return rs; 

190     } 

191   

192     public static void setRs(ResultSet rs) { 

193         SqlHelper.rs = rs; 

194     } 

195       

196       

197 }

dbinfo.properties文件的代码：

连接oracle的如下:  www.2cto.com

driver=oracle.jdbc.driver.OracleDriver
url=jdbc\:oracle\:thin\:@127.0.0.1\:1521\:oraclezw
username=*
password=*