Example: A Servelets program to print a message.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class HelloWorldServlet extends HttpServlet {

   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Hello World Servlet</title>");
      out.println("</head>");
      out.println("<body>");
      out.println("<h1>Hello, World!</h1>");
      out.println("</body>");
      out.println("</html>");
   }
}

----------  OR  -----------

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class HelloWorldServlet extends HttpServlet {
   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html><body>");
      out.println("<h1>Hello World!</h1>");
      out.println("</body></html>");
   }
}
Example: A Servelets program to print user-accepted data from a Form.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class FormServlet extends HttpServlet {

   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      doPost(request, response);
   }

   public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Form Servlet</title>");
      out.println("</head>");
      out.println("<body>");
      out.println("<h1>Form Data</h1>");
      out.println("<p>User Name: " + request.getParameter("uname") + "</p>");
      out.println("<p>User Email: " + request.getParameter("uemail") + "</p>");
      out.println("</body>");
      out.println("</html>");
   }
}

NB: Here, 'uname' and 'uemail' are the name of html Form user name and user email box.
Example: A Servelet program to handle form submissions and displays the submitted data on the web page.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class FormServlet extends HttpServlet {
   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html><body>");
      out.println("<form method='post' action=''>");
      out.println("Name: <input type='text' name='uname'><br>");
      out.println("Email: <input type='text' name='uemail'><br>");
      out.println("<input type='submit' value='Submit'>");
      out.println("</form>");

      String name = request.getParameter("uname");
      String email = request.getParameter("uemail");

      if (uname != null && uemail != null) {
         out.println("<p>User Name: " + uname + "</p>");
         out.println("<p>User Email: " + uemail + "</p>");
      }

      out.println("</body></html>");
   }

   public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      doGet(request, response);
   }
}
Example: A Servelets program to print user-accepted data from a Form/web page.
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DatabaseServlet extends HttpServlet {

   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Database Servlet</title>");
      out.println("</head>");
      out.println("<body>");
      out.println("<h1>Retrieve MySql Database Data</h1>");
      
      try {
         // Load the JDBC driver for MySql database
         Class.forName("com.mysql.jdbc.Driver");
         
         // Connectivity code to the MySql database
         String url = "jdbc:mysql://localhost/databasename";
         String username = "root";
         String password = "password";
         Connection conn = DriverManager.getConnection(url, username, password);
         
         // Create the SQL statement
         Statement stmt = conn.createStatement();
         String sql = "SELECT * FROM tablename";
         
         // Execute the SQL statement
         ResultSet rs = stmt.executeQuery(sql);
         
         // Display the results
         while(rs.next()) {
            out.println("<p>User Name: " + rs.getString("uname") + "</p>");
            out.println("<p>User Email: " + rs.getString("uemail") + "</p>");
         }
         
         // Clean up
         rs.close();
         stmt.close();
         conn.close();
         
      } catch(Exception e) {
         out.println("<p>Error: " + e.getMessage() + "</p>");
      }
      
      out.println("</body>");
      out.println("</html>");
   }
}

Example: A Servelets program to store user data in a session and displays it on the web page.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class SessionServlet extends HttpServlet {
   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      HttpSession session = request.getSession();

      String vname = request.getParameter("uname");

      if (vname != null) {
         session.setAttribute("name", sname);
      }

      out.println("<html><body>");
      out.println("<form method='post' action=''>");
      out.println("Name: <input type='text' name='uname'><br>");
      out.println("<input type='submit' value='Submit'>");
      out.println("</form>");

      String sessionName = (String)session.getAttribute("sname");

      if (sessionName != null) {
         out.println("<p>Name stored in session: " + sessionName + "</p>");
      }

      out.println("</body></html>");
   }

   public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      doGet(request, response);
   }
}

Loading

Categories: Java

0 Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.