by Dinesh Thakur Category: Servlet with MySql Database

This function Is a synonym for LENGTH ().

First I made a table in database named 'dbase' within the reference of mySql(Php myAdmin). I import all the required java packages from java library. After then i declare a class named 'MySqlOCTETLENGTHFunction', which extends the 'HttpServlet'. After i use serviceMethod() responsible for the getting request from doGet() method. Then, i load all required drivers for database accessing. Then i declare some variables like connection (this will create a bridge between the database and the java code or in other words Frontend and Backend with the help of loaded drivers. The other variable is to declare will be resultset it will use to get the value from required columns and rows into on to the database. The next one will be the preparedStatement the object of the variable is ps. this will be responsible for executing the selected query like executeQuery() as (Select OCTET_LENGTH('mysql')).The next step to use doGet() method which will bring the output on a web browser.

On the web browser for making Output a effective look we will use 'HTML' code and tags to bring the Output in tabular form as required.

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 MySqlOCTETLENGTHFunction 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 OCTET_LENGTH('mysql')");
                     rs = ps.executeQuery();
                                String title = "Using OCTET_LENGTH 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 Is </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>MySqlOCTETLENGTHFunction</servlet-name>
   <servlet-class>MySqlOCTETLENGTHFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlOCTETLENGTHFunction</servlet-name>
   <url-pattern>/MySqlOCTETLENGTHFunction</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.



Related Articles