JDBC Learning Note (21): Designing patterns using template methods

To add a Find method to the parent class:

1  PackageCom.xxyh.jdbc.dao.refactor;2 Importjava.sql.Connection;3 Importjava.sql.PreparedStatement;4 ImportJava.sql.ResultSet;5 Importjava.sql.SQLException;6 Importcom.xxyh.jdbc.JdbcUtils;7 Importcom.xxyh.jdbc.dao.DaoException;8  Public Abstract classAbstractdao {9     Ten      PublicObject Find (String sql, object[] args) { OneConnection conn =NULL; APreparedStatement PS =NULL; -ResultSet rs =NULL;  -         Try { theconn =jdbcutils.getconnection (); -PS =conn.preparestatement (SQL); -              for(inti = 0;i < args.length; i++)  -Ps.setobject (i+1, Args[i]); +rs =ps.executequery (); -Object obj =NULL; +              while(Rs.next ()) { Aobj =RowMapper (RS); at             } -             returnobj; -}Catch(SQLException e) { -             Throw Newdaoexception (E.getmessage (), e); -}finally { - Jdbcutils.close (RS, PS, conn); in         } -     } to      +     Abstract protectedObject RowMapper (ResultSet rs)throwsSQLException; -      the     /** * * Dynamic Update $      * @paramSQL UPDATE statementPanax Notoginseng      * @paramargs need to pass in Parameters -      * @returnreturns the number of result bars the      */ +      Public intUpdate (String sql, object[] args) { AConnection conn =NULL; thePreparedStatement PS =NULL; +ResultSet rs =NULL; -         Try { $conn =jdbcutils.getconnection (); $PS =conn.preparestatement (SQL); -              -              for(inti = 0; i < args.length; i++) thePs.setobject (i+1, Args[i]); -             Wuyi             returnps.executeupdate (); the}Catch(SQLException e) { -             Throw Newdaoexception (E.getmessage (), e); Wu}finally { - Jdbcutils.close (RS, PS, conn); About         } $     } -}

Refine the implementation class:

1  PackageCom.xxyh.jdbc.dao.refactor;2 ImportJava.sql.ResultSet;3 Importjava.sql.SQLException;4 ImportCom.xxyh.jdbc.domain.User;5  Public classUserdaoimplextendsabstractdao{6     7      PublicUser Finduser (String name) {8String sql = "SELECT ID, Name, money, birthday from user where name=?";9object[] args =Newobject[] {name};TenObject user =Super. Find (sql, args); One         return(user) user; A     } -      -      Public voidDelete (user user) { theString sql = "Delete from user where id=?"; -object[] args =Newobject[] {user.getid ()}; -         Super. Update (sql, args); -     } +      -      Public voidUpdate (user user) { +String sql = "Udpate user set name=?,birthday=?,money=?" where id=? "; Aobject[] args =Newobject[] {user.getname (), User.getbirthday (), at User.getmoney (), User.getid ()}; -         Super. Update (sql, args); -     } - @Override -     protectedUser RowMapper (ResultSet rs)throwsSQLException { -User User =NewUser (); inUser.setid (Rs.getint ("id")); -User.setname (rs.getstring ("name")); toUser.setmoney (Rs.getfloat ("Money")); +User.setbirthday (rs.getdate ("Birthday")); -         returnuser; the     } *}

JDBC Learning Note (21): Designing patterns using template methods