by Dinesh Thakur Category: Servlet with MySql Database

This Function Will Returns the value of pi.

i made a database first named 'dbase' within the reference of mySql(php myAdmin). Then i import all the required java packages from the java library. Here after, i made a class named 'MySqlPIFunction', which extends 'HttpServlet' Completely. Then i use service()Method that will help to getting request from the doGet()Method for output. After that, i loaded all the required drivers that are useful for database accessing. Then i declare the mandatory drivers as i use 'connection' variable that will use to create a link between database and java code. After that i declare 'resultSet()that will use to get value from the columns and rows as selected table. Here after i use to declare 'preparedStatement' that will act as to executing selected query like executeQuery() as (Select PI()). In the last i use doGet()Method which will bring the output on the web browser.

On the web Browser i use 'Html' tags to print the output in tabular form on the web browser this will present output in a manner way. 

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 MySqlPIFunction 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 PI()");
                 rs = ps.executeQuery();
                             String title = "Using PI 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>MySqlPIFunction</servlet-name>
   <servlet-class>MySqlPIFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlPIFunction</servlet-name>
   <url-pattern>/MySqlPIFunction</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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