Using beans in JSP to encapsulate the common features of a database

js| Package | data | database

Using beans in JSP to encapsulate the common features of a database

1. Create a Bean

Package guestbook;


import java.sql.*;








public class Sql_data


{


String sdbdriver= "Sun.jdbc.odbc.JdbcOdbcDriver";


String sconnstr= "Jdbc:odbc:guestbook";


Connection Conn=null;


ResultSet Rs=null;


public Sql_data ()


    {


try{


Class.forName (Sdbdriver);


        }


catch (java.lang.ClassNotFoundException e)


        {


System.err.println ("Sql_data ():" +e.getmessage ());


        }


    }





public void Executeinsert (String sql)


    {


Try


        {


conn=drivermanager.getconnection (SCONNSTR);


Statement stmt=conn.createstatement ();


stmt.executeupdate (SQL);


        }


catch (SQLException ex)


{


System.err.println ("Sql_data.executeupdate:" +ex.getmessage ());


        }


    }





public ResultSet executequery (String sql)


    {


Rs=null;


Try


        {


conn=drivermanager.getconnection (SCONNSTR);


Statement stmt=conn.createstatement ();


rs=stmt.executequery (SQL);


}


catch (SQLException ex)


        {


System.err.println ("Sql_data.executequery:" +ex.getmessage ());


        }


    }





public void Executedelete (String sql)


    {


Try


        {


conn=drivermanager.getconnection (SCONNSTR);


Statement stmt=conn.createstatement ();


Stmt.executeupdate (SQL);


        }


catch (SQLException ex)


        {


System.err.println ("Sql_data.executedelete:" +ex.getmessage ());


        }


    }


}

2. Declare the Bean in the JSP:

......

<jsp:usebean id= "Sqlbean" scope= "session" class= "Guestbook.sql_data"/>

<%! String sql,name;%>

<%

Sql= "SELECT * from table";

ResultSet rs=sqlbean.executequery (SQL);

while (Rs.nex ()) {

Name=rs.getstring ("name")

}

%>

......

Name:<%=name%>

......

<%

Rs.close ();

%>

......