by Dinesh Thakur Category: Servlet with MySql Database

This function will insert a substring at the specified position up to the specified number of characters.

We have created database named 'dbase'. After that a class is been declared named 'MySqlINSERTFunction' extends the 'HttpServlet'. With that kind of efforts, we need to define some methods, which do their job for producing output. After we just declare Service method () (service method does the job of calling doGet() method for getting request). Some variables also define as Connection,Resultset,PreparedStatement. Connection variable use to create link between database and actual code (Frontend and Backend). PreparedStatement will use to send the query to database like (Select INSERT('MySQL',3,0,'Java')). This statement will work according to condition it shows. Now the next method executeQuery() will execute desired query and statement. And in the end doGet() method will be used to fetch the result on a web browser.

To feel look good the result we use a tabular form concept. For this kind of requirement, we use ‘HTML’ coding and some of tags to use Output in Designer look to show on a 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 MySqlINSERTFunction 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 INSERT('MySQL',3,0,'Java') as ins");
                rs = ps.executeQuery();
             String title = "Using INSERT 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>MySqlINSERTFunction</servlet-name>
   <servlet-class>MySqlINSERTFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlINSERTFunction</servlet-name>
   <url-pattern>/MySqlINSERTFunction</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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