by Dinesh Thakur Category: Servlet with MySql Database

This Function will make a computation of given expressions.

I make a table named 'worker' into a database named 'dbase' within the reference of mySql(php myAdmin).Then We have to call The Packages From java Library. Then i Make a Class Named 'MySqlOperatorPrecedence' Extends "HttpServlet". After, Initializing The Class i Declare The Methods Public void Service()Method (The service method call the doGet method for a GET request from User) and In That The Objects called "Response Object" and "Request Object Which will Work According To Work. After that i Load the Driver and Make Variables Of Resultset,Connection to establish The link between database and Query that Execute The Condition after Calling. After Declaring The Prepared statement i have to put the Query ("SELECT name, salary, 12*salary+100 cal FROM worker").After that i Use executeQuery() Method to Extract the Result On a Web Browser.

I Use 'HTML' code and some tags, which will show the output in 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 MySqlOperatorPrecedence 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 name, salary, 12*salary+100 cal FROM worker");
                   rs = ps.executeQuery();
                               String title = "Employee's Info With Using Of Operator Precedence";
                   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>Name</th><th>Salary</th><th>Calculation</th>\n"+ "</body> </html>");
                   while(rs.next())
                       {
                            String nm = rs.getString("name");
                                        int sal = rs.getInt("salary");
                                        int c=rs.getInt("cal");
                            disp.println("<tr><td align=\"center\">" + nm +  "<td align=\"center\">" + sal +"<td align=\"center\">" + c +"</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>MySqlOperatorPrecedence</servlet-name>
   <servlet-class>MySqlOperatorPrecedence</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlOperatorPrecedence</servlet-name>
   <url-pattern>/MySqlOperatorPrecedence</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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