by Dinesh Thakur Category: Servlet with MySql Database

The Function 'CONV' will convert numbers between Number bases.

i make a table in database named 'dbase' with required fields and values too. The database made within the reference of mySql(php myAdmin). Then i import all the required java packages from java library with required Condition. I made a class named 'MySqlCONVFunction' which extends 'HttpServlet'. Here now i use serviceMethod() which will act a role of getting request from doGet()Method for output. Before declaring the variable i loaded here all required drivers for the database accessing. Here now time to declaring the variables i declare 'connection' this variable will use to create the link between database and the actual code. The other i declare is 'resultSet' this will use to fetch the value from required columns and rows as required condition. Here i also declare 'preparedStatement' this will get in the use to executing the selected Query like executeQuery() as (Select CONV(5,17,9)). Here in the last instance of coding i just use doGet()method which will bring the output on the web browser.

While the programming i use 'HTML' code or tags to bring output in tabular form on the web Browser. 

 
EXAMPLE
 
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MySqlCONVFunction extends HttpServlet
 {
   public void service(HttpServletRequest rq, HttpServletResponse rp)throws IOException, ServletException
    {
      rp.setContentType("text/html");
      PrintWriter disp = rp.getWriter();
      String driver = "com.mysql.jdbc.Driver";
      String url = "jdbc:mysql://localhost/dbase";
      String uid = "root";
      String psw = "root";
      Connection con=null;
      PreparedStatement ps = null;
      ResultSet rs;
      try
       {
         Class.forName(driver);
         con = DriverManager.getConnection(url,uid,psw);
         ps=con.prepareStatement("Select CONV(5,17,9)");
         rs = ps.executeQuery();
             String title = "Using CONV Function";
         String docType ="<!doctype html public \"-//w3c//dtd html 4.0 " + "transitional//en\">\n";
             disp.println(docType + "<html>\n" + "<head><title>" + title + "</title></head>\n" +
         "<body bgcolor=\"#f4efef\">\n" + "<h1 align=\"center\">" + title + "</h1>\n" + "<ul>\n" +
             "<table width=\"50%\" border=\"1\" align=\"center\">\n" + "<th>Value</th>\n"+ "</body> </html>");
         while(rs.next())
           {
             String val = rs.getString(1);
                 disp.println("<tr><td align=\"center\">" + val +"</td></tr>" );  
           }     
       }  
                 catch(Exception e) 
                        {
                           e.printStackTrace();
                        }
                           disp.close();
     }
                       public void doPost(HttpServletRequest rq,HttpServletResponse rp)throws IOException,ServletException
                           {
                                 doGet(rq,rp);
                           }
 }
 
WEB.XML
 
<servlet>
   <servlet-name>MySqlCONVFunction</servlet-name>
   <servlet-class>MySqlCONVFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlCONVFunction</servlet-name>
   <url-pattern>/MySqlCONVFunction</url-pattern>
</servlet-mapping>




About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.



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