by Dinesh Thakur Category: Servlet with MySql Database

This function will sort the selected column into descending order.

First we make a table named 'org' into a database named 'dbase' within the reference of mySql(php myAdmin).Now we need to import all the java packages required by user. After calling all the packages we make a class named 'JavaServletSortDESC' extends the 'HttpServlet'.now to use serviceMethod() which will getting the request from doGet() for output. After then load all the required Drivers. Some mandatory variable also to be define like resultset this variable will responsible for getting the value from desired Columns and rows. Connection variable which will establish the link between the database and actual code(frontEnd and backEnd).and the PreparedStatement this variable does execute the given query like executeQuery() as (SELECT last_name, job_id, dept_id, hire_date FROM org ORDER BY hire_date DESC).and in the end the doGet() method has to be used while getting the Output on the web Browser.

On the web browser the output seems to be normal But to get the Output in a designer or efficient look we use 'HTML' code or Tags for getting output in tabular form on a web browser.    

 
EXAMPLE
 
JavaServletSortDESC
 
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 JavaServletSortDESC 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 last_name, job_id, dept_id, hire_date FROM org ORDER BY hire_date DESC");
                     rs = ps.executeQuery();
                              String title = "Employee's Data In Descending Order";
                    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>Last Name</th><th>Job Id</th><th>Department ID</th><th>Hire Date</th>\n"+ "</body> </html>");
                   while(rs.next())
                             {
                                 String l_name = rs.getString("last_name");
                                            int j_id = rs.getInt("job_id");
                                            int d_id = rs.getInt("dept_id");
                                                      int dt = rs.getInt("hire_date");
                                  disp.println("<tr><td align=\"center\">"+ l_name +"<td align=\"center\">" + j_id +  "<td align=\"center\">" + d_id + 
                                  "<td align=\"center\">" + dt + "</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>JavaServletSortDESC </servlet-name>
   <servlet-class>JavaServletSortDESC </servlet-class>
</servlet>
<!-- servlet mapping -->
<servlet-mapping>
   <servlet-name>JavaServletSortDESC</servlet-name>
   <url-pattern>/JavaServletSortDESC </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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