Retrieving blob values from database in string format Java Program

import java.sql.*;

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

Class.forName("com.mysql.jdbc.Driver");  //type 4 driver
 Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/college","root","rat");//connection
System.out.println("Connection successful:"+con);
 PreparedStatement ps=con.prepareStatement("select * from login");
 ResultSet res=ps.executeQuery();
 res.next();

        Blob b= res.getBlob(1);
        long len=b.length();
       
        byte value[]=b.getBytes(1, (int)(len));
        String str=new String(value);
        System.out.println(str);
}
}