by Dinesh Thakur Category: Servlet with MySql Database

This Function will return the length of a string in bytes.

First i made a database named 'dbase' within the reference of mySql(php myAdmin) with required fields and values in it. Then according to need of program, I import all the java packages from the java library. I create a class named 'MySqlLENGTHFunction', which extends 'HttpServlet'. Then, i use serviceMethod() that will bring the request from doGet()Method for output on web browser. After, using serviceMethod() i loaded all the required Drivers mandatory for database accessing. Here after, i declare variables as first i use 'connection' this will use to create a link between database and the java code. Then i use 'resultSet' this use to get the value from selected columns and rows. And the other one i use is 'preparedStatement' this will use to executing the selected Query like executeQuery() as (Select LENGTH('MySql')).I use doGet()Method for output on the web browser.

Now to get the output on the web browser in an impressive look I use 'HTML' code and some of these tags, which will bring output in the tabular form on the 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 MySqlLENGTHFunction 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 LENGTH('MySql') as lnth");
                    rs = ps.executeQuery();
                 String title = "Using 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>MySqlLENGTHFunction</servlet-name>
   <servlet-class>MySqlLENGTHFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlLENGTHFunction</servlet-name>
   <url-pattern>/MySqlLENGTHFunction</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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