by Dinesh Thakur Category: Servlet with MySql Database

The Function 'ABS(Absolute)' will show the Absolute value of a content or Number.

First i import all the required java packages from java library. Then after i made a class named 'MySqlABSOLUTEFunction' extends the 'HttpServlet'.i use the serviceMethod() which is responsible for the getting request from doGet() method. Then after need to load all the drivers as required. And to declare the mandatory variables like Connection (the variable Connection will use to establish the link between database and java code(actual code).ResultSet the variable Resultset does the job to fetch the value from required columns and rows.preparedStatement this variable use to execute the query like executeQuery() as (Select ABS('-39')) and after then i use doGet() method to get the output on the web Browser.

To get the Output in an impressive look, i use some tags of 'HTML' Code which will bring the Output in tabular form on a 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 MySqlABSOLUTEFunction 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 ABS('-39')");
         rs = ps.executeQuery();
             String title = "Using ABS(Absolute) 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>MySqlABSOLUTEFunction</servlet-name>
   <servlet-class>MySqlABSOLUTEFunction</servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>MySqlABSOLUTEFunction</servlet-name>
   <url-pattern>/MySqlABSOLUTEFunction</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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