by Dinesh Thakur Category: Servlet with MySql Database

The Function 'COS'(Cosine) will return the cosine value of any radian expression.

i make a table in database named 'dbase' with required fields and values in it. Database is been created in the reference of mySql(php myAdmin). Here i import all the java packages required during the program from java library. Then i make a class named 'MySqlCOSFunction' extends the 'HttpServlet'. Here i use serviceMethod() which will bring the request from doGet()Method for Output. Here the next step will be to loaded all required drivers for database accessing. Now i will declare the mandatory variables like 'connection' this variable will take over to create a link between the database and the java code. The next one will be the 'resultSet' this variable will use to retrieve the value from columns and rows as required the query.the other one will be the 'preparedStatement' this variable is must use for the executing selected query like executeQuery as (Select COS('60')). Here i use doGet()Method for getting output on the web Browser.

To get output on the web browser i use 'HTML' code and tags that will present the output in a tabular form on the web browser.

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 MySqlCOSFunction 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 COS('60')");
          rs = ps.executeQuery();
              String title = "Using COS 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</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>MySqlCOSFunction</servlet-name>
   <servlet-class>MySqlCOSFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlCOSFunction</servlet-name>
   <url-pattern>/MySqlCOSFunction</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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