Model layer dao -- SqlHelper

Paste the SqlHelper code:

001 /**

002 * function: encapsulate database operations

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 // database operations required

013 private static Connection ct = null;

014 private static PreparedStatement ps = null;

015 private static ResultSet rs = null;

016

017 // some constants

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 FCM = null;

025 private static InputStream is = null;

026

027 // static, only once

028 static {

029 try {

030 pp = new Properties ();

031 // by default, the main directory read is in the bin directory of the main directory of tomcat;

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

033 // The main directory read by default is under the src directory;

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

035 pp. load (is );

036 // fix some constants

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

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

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

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

041

042 // load the driver

043 Class. forName (driver );

044} catch (Exception e ){

045 e. printStackTrace ();

046 // TODO: handle exception

047} finally {

048 // close the resource

049 // if (FS! = Null ){

050 // try {

051 // FCM. close ();

052 //} catch (IOException e ){

053 // TODO Auto-generated catch block

054 // e. printStackTrace ();

055 //}

056 // FS = 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 // get the connection

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 // close the resource

080 // disabled by the caller

081}

082 return ct;

083}

084

085 // provide query

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

087 {

088 try {

089 // get the connection

090 ct = getConnection ();

091 // execute the query statement

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.exe cuteQuery ();

102} catch (Exception e ){

103 e. printStackTrace ();

104 // TODO: handle exception

105} finally {

106 // close the resource

107 // close it by yourself

108}

109 return rs;

110}

111

112 // simple addition, deletion, and modification

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.exe cuteUpdate ();

126} catch (Exception e ){

127 e. printStackTrace ();

128 // TODO: handle exception

129} finally {

130 // close the resource

131}

132}

133

134 // provides a method to disable Resources

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 // obtain 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 file code:

The connection to oracle is as follows: www.2cto.com

Driver = oracle. jdbc. driver. OracleDriver
Url = jdbc \: oracle \: thin \: @ fig \: 1521 \: oraclezw
Username = *
Password = *