by Dinesh Thakur Category: Servlet with MySql Database

This function will Returns the tangent of numeric expression expressed in radians.

I make a table in database named 'dbase' which is been created in the reference of mySql(php myAdmin). Then i import all the required java packages from java library as required from program need. Then, i make a class named 'MySqlTANFunction' extends 'HttpServlet'. After that i use serviceMethod()that will get request from doGet()method for output on the web browser. Before declaring the variables as required, i loaded all the mandatory drivers for database accessing. Here i declare 'Connection' this variable will be the responsible for the making bridge or path between the database and the java code. The other one will be the 'resultSet' this one will help to fetch the values from the selected columns and the rows. Here i declare 'preparedStatement' this will bring execute the selected query like executeQuery() as (Select TAN(1)).Here i use doGet()Method that will bring the output on the web browser.

To make output Impressive I use 'HTML' tags to get Output in tabular form on a web browser.  

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 MySqlTANFunction 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 TAN(1)");
                    rs = ps.executeQuery();
                String title = "Using TAN 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>MySqlTANFunction</servlet-name>
   <servlet-class>MySqlTANFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlTANFunction</servlet-name>
   <url-pattern>/MySqlTANFunction</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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