by Dinesh Thakur Category: Servlet with MySql Database

This Function Will Return the leftmost number of characters as specified.

First i made a table with required fields and values in that into a database named 'dbase' with the reference of mySql(php Myadmin). Then i import all the required packages from java library. Then i made a class named 'MySqlLeftCaseFunction' extends the 'HttpServlet'.then i use serviceMethod() which will use to getting request from the doGet()Method for Output. Then i load all the required Drivers. Then, i declare some mandatory variables like connection (Connection variable is been used to make a bridge or link between database and actual code (java code)). As after creating link between both platforms, i declare resultSet, which will be use to fetch the values from required fields according to user. The other one variable is preparedStatement the object of this variable is 'ps' this will use to execute the query like executeQuery() as(Select LEFT('MySqlJava','5')). To in the end i use doGet()Method for getting value on the web Browser.

On the web Browser i use 'Html' tags to print the output in tabular form on the web browser this will present output in a manner 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 MySqlLeftCaseFunction 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 LEFT('MySqlJava','5') as lft");
                   rs = ps.executeQuery();
                String title = "Using LeftCase 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>MySqlLeftCaseFunction</servlet-name>
   <servlet-class>MySqlLeftCaseFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlLeftCaseFunction</servlet-name>
   <url-pattern>/MySqlLeftCaseFunction</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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