by Dinesh Thakur Category: Servlet with MySql Database

The 'Arithmetic Operator' does the mathematical computation in MySql.

 

First i make a table in database named 'dbase'. All the fields in table must be filled with required values. After then i import all the required java packages from java library. Then i made a class named 'MySqlArithmeticOperator' extends the'HttpServlet'. Then i use serviceMethod() which is responsible for getting request from doGet() method for Output. After then i load all the required driver for database connection. Then i declare mandatory variables as required like connection (this variable will create a link between database and actual code(java code)).After declaring connection i declare resultSet variable this variable will get the value from the required columns and values within it's own object rs. The other variable will be prepared Statement this variable will be responsible for executing the Selected Query like executeQuery() as (SELECT name, salary,salary + 300 cal FROM worker).then i use doGet() method for getting output on the web browser.

to getting output in tabular form on web browser i used 'HTML' code and the tags for showing output in manner form also.  

 
EXAMPLE
 
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 MySqlArithmeticOperator 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,salary + 300 cal FROM worker");
            rs = ps.executeQuery();
                String title = "Employee's Info And Salary With Using Of Arithmetic Operator ";
            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>MySqlArithmeticOperator</servlet-name>
   <servlet-class>MySqlArithmeticOperator</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlArithmeticOperator</servlet-name>
   <url-pattern>/MySqlArithmeticOperator</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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