Sessionex1
- 2. SiteHome.html <html> <head> <title>URL Rewriting Example</title> </head> <body> This is the Home page for the example to demonstrate how to use <BR> URL Rewriting and Hidden form fields to mantain the client state. <BR><BR> <a href="Login.html">Login</a> </body> </html>
- 4. Login.html <html> <head> <title>URL Rewriting Example</title> </head> <body> <form name="loginform" action="login" method="post"> <table border="0"> <tr> <td>UserName:</td> <td><input type="text" name="uname"></td> </tr> <tr> <td>Password:</td> <td><input type="password" name="password"></td> </tr> <tr> <td colspan="2" align="center"><input type="submit"></td> </tr> </table> </form> </body> </html>
- 8. • Once you click on submit button • Post method is executed, data is submitted into server in the form of request object • Later LoginServlet program gets executed because of <form action=“login”> whose url pattern servlet name is “LoginServlet” (see web.xml file)
- 9. LoginServlet.java package com.rajendra.servlets; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.*; import javax.servlet.http.*; public class LoginServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String uname=request.getParameter("uname"); String pass=request.getParameter("password");
- 10. LoginServlet.java response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>"); out.println(" <BODY>");
- 11. LoginServlet.java if (uname==null||uname.equals("")){ out.println("<b><i>Username Cannot be empty</i></b>"); RequestDispatcher rd=request.getRequestDispatcher("/Login.html"); rd.include(request, response); return; } if (pass==null||pass.equals("")){ out.println("<b><i>Password Cannot be empty</i></b>"); RequestDispatcher rd=request.getRequestDispatcher("/Login.html"); rd.include(request, response); return; } UserDAO ud=new UserDAO();
- 12. LoginServlet.java if(ud.validate(uname,pass)){ out.println("<table width=98% height=95% border=1><tr>"); out.println("<td height=45 colspan=2 align=center><font size=5>My Email Site</font></td>"); out.println("</tr><tr>"); out.println("<td width=12% height=545 align=center valign=top>"); out.println("<p> </p><p><font size=4>"); out.println("<a href='inbox?uname="+uname+"'>InBox</a>"); out.println("</font></p>"); out.println("<p><font size=4>Bulk Mail</font></p>"); out.println("<p><font size=4>Sent Items</font></p>"); out.println("<p><font size=4>Write Mail</font></p>"); out.println("<p><font size=4><a href='Login.html'>Logout</a></font></p>"); out.println("<p> </p></td>"); out.println("<td width=88% align=left valign=top><p> </p>"); out.println("<p><font size=4>Welcome, "+uname+"</font></p></td>"); out.println("</tr><tr align=center>"); out.println("<td colspan=2><div align=center>@Copyrights 2001-08</div></td>"); out.println("</tr></table>");
- 13. LoginServlet.java }//if else{ out.println("<b><i>Username or Password given are not valid</i></b>"); RequestDispatcher rd=request.getRequestDispatcher("/Login.html"); rd.include(request, response); return; } out.println(" </BODY>"); out.println("</HTML>"); out.flush(); out.close(); } }
- 14. • Now servlet container calls the public service() and which intern calls the protected service() method • Protected service() calls doPost() method
- 19. • Now if() conditions becomes false, (server side validation for username and password). • Now UserDao object is created to call validate() method
- 21. if(ud.validate(uname,pass)) • if(ud.validate(uname,pass)) • if(ud.validate(rajendra,raj)) method calling • Now control goes to validate () method in UserDao class
- 22. UserDAO.java package com.rajendra.servlets; import java.sql.*; public class UserDAO { public boolean validate(String uname, String pass){ try { Connection con=DriverConnection.getConnection(); Statement st=con.createStatement(); ResultSet rs=st.executeQuery( "select count(*) from userdetails where uname='"+uname+"' and pass='"+pass+"'"); return rs.next(); }//try catch(Exception e){ e.printStackTrace(); } return false; } }
- 26. • return rs.next(); • return true;//it returns true as resultset contains next element • Now control come back to the LoginServlet.java
- 27. if(ud.validate(uname,pass)){ //if condition becomes true out.println("<table width=98% height=95% border=1><tr>"); out.println("<td height=45 colspan=2 align=center><font size=5>My Email Site</font></td>"); out.println("</tr><tr>"); out.println("<td width=12% height=545 align=center valign=top>"); out.println("<p> </p><p><font size=4>"); out.println("<a href='inbox?uname="+uname+"'>InBox</a>"); out.println("</font></p>"); out.println("<p><font size=4>Bulk Mail</font></p>"); out.println("<p><font size=4>Sent Items</font></p>"); out.println("<p><font size=4>Write Mail</font></p>"); out.println("<p><font size=4><a href='Login.html'>Logout</a></font></p>"); out.println("<p> </p></td>"); out.println("<td width=88% align=left valign=top><p> </p>"); out.println("<p><font size=4>Welcome, "+uname+"</font></p></td>"); out.println("</tr><tr align=center>"); out.println("<td colspan=2><div align=center>@Copyrights 2001-08</div></td>"); out.println("</tr></table>");