by Dinesh Thakur Category: Servlet with MySql Database

Will Return Log value of selected number.

First, I make a table in database named 'dbase' within the reference of mySql(php myAdmin). Then i import all the mandatory java packages from the java library as required for program. I made a class named 'MySqlLNFunction', which extends 'HttpServlet'. I use serviceMethod() which is been carry the request from doGet()Method for Output. Then before, declaring the variable i loaded all the required drivers before for database accessing. Here i declare the variables like 'connection' this variable will create a link between database and java code. Then, i call 'resultSet' this will be responsible for Getting value from the selected columns and the rows. Then i declare 'preparedStatement' which will get to execute the selected query like executeQuery() as (Select LN(5)).here i use doGet()Method which will use to get output on the web browser.

While getting Output on the Web Browser we use 'HTML' Code or some of these tags to present Output in tabular form.

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 MySqlLNFunction 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 LN(5)");
                       rs = ps.executeQuery();
                    String title = "Using LN(LOGRITHM) 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>MySqlLNFunction</servlet-name>
   <servlet-class>MySqlLNFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlLNFunction</servlet-name>
   <url-pattern>/MySqlLNFunction</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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