by Dinesh Thakur Category: Servlet with MySql Database

This Function Will Return the substring as specified.

First, i use to make a database named 'dbase' within the reference of mySql(php myAdmin). Then i use to import all required java package from java library. Then after calling all the packages, i made a class named 'MySqlSUBSTRFunction', which extends 'HttpServlet'. I use service()Method which will use to getting the request from doGet()Method for output. Then i loaded all the required drivers for database accessing. After loading driver, I declare the variables like i use 'connection' variable that will use to create a link between the database and the java code. Then after, i use 'resultSet' that will act as to fetching value from the selected column and rows. I use 'preparedStatement' that will use to executing the selected query like executeQuery as (Select SUBSTR('servletmysql',5,4)). I use doGet()Method in last interface which will use to get output on the web browser.

I use here some tags of 'HTML' that will bring output in a 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 MySqlSUBSTRFunction 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 SUBSTR('servletmysql',5,4)");
                   rs = ps.executeQuery();
               String title = "Using SUBSTR 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>MySqlSUBSTRFunction</servlet-name>
   <servlet-class>MySqlSUBSTRFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlSUBSTRFunction</servlet-name>
   <url-pattern>/MySqlSUBSTRFunction</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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