Q) Develop a JDBC application that connects to any kind of database using any driver without changing the source code

A)

->in order to achieve driver vendor independency and database vendor independency we should not hard code driver class name, connection string, user name and password in the application.

->we have to take a separate properties file. In this text file we specify database connection details. From JDBC program we read this file programmatically, if driver changes or database changes or user name or password changes we need to change the properties file, but not the JDBC application source code.

->db.properties

->it is notepad file filename is db and extension is properties.

Driver=sun.jdbc.odbc.JdbcOdbcDriver

url=jdbc:odbc:mydsn

user=scott

password=tiger.

//Genericconnection.java

importjava.sql.DriverManager;

import java.sql.Connection;

importjava.io.FileInputStream;

importjava.util.Properties;

class Genericconnection {

       public static void main(String[] args) throws Exception {

              Properties p= new Properties();

              FileInputStream fis= new FileInputStream("db.properties");//opening the file

              p.load(fis);//transaction file connected into object.2

              String driver=p.getProperty("Driver");

              String cs=p.getProperty("url");

              String user=p.getProperty("user");

              String pwd=p.getProperty("password");

              Class.forName(driver);

              Connection con=DriverManager.getConnection(cs,user,pwd);

              System.out.println("connected");

              con.close();//closing the dbconnection.

              fis.close();//closing the properties file.

       }

}