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Thread: how to use jsp / servlet

  1. #1
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    Default how to use jsp / servlet

    I need help making proper way to make website using jsp/servlet.

    file path: WebContent > login.jsp
           <form method="post" action="servlet">
              what's your username?<br /> <input type="text" name="usernameF" /><br />
              what's your password?<br /> <input type="password" name="passwordF" /><br />
    	  <input type="submit" name="submitB" value="login" />
           </form>


    file path: Java Resources > src > servlet.java
    ...
    protected void doGet(HttpServletRequest request,
    			HttpServletResponse response) throws ServletException, IOException {
    		response.setContentType("text/html"); // useing html
     
    		PrintWriter out = response.getWriter(); // write to browser
    		HttpSession session = request.getSession(true);
     
    		if (request.getParameter("submitB") != null) {
    			if (usernameR.equals("")) {
    				out.print("Error enter name");
    			} else if (passwordR.equals("")) {
    				out.print("Error enter password");
    			} else {
    				session.setAttribute("username", usernameR);
    				response.sendRedirect(login.jsp);
    			}
                    }
    }
    ...



    Question 1: is this the proper way of using jsp/servlet?
    Question 2: when user hit submit button in html form than it will run java code. but in servlet.java class the error will never print on login.jsp. how can i print errors on login.jsp? by error i mean:
    out.print("Error enter name");
    out.print("Error enter password");

    p.s i look tutorial online but they only use jsp which is not good coding. if you have proper jsp/servlet tutorial let me know.

    Thank you so much


  2. #2
    Member andbin's Avatar
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    Default Re: how to use jsp / servlet

    Quote Originally Posted by game06 View Post
    Question 1: is this the proper way of using jsp/servlet?
    Question 2: when user hit submit button in html form than it will run java code. but in servlet.java class the error will never print on login.jsp.
    First, Servlets it's better if they are in a package, not in the "default" package.
    Second, you must map, into the web.xml, the url /servlet (or whatever url you would like to specify in the action attribute) to your servlet. It's not automatic. Putting action="servlet" doesn't mean, automatically, that a servlet named "servlet" is invoked!
    Third, in the "good" use of JSP/Servlet, a Servlet should not do output directly to the response. At most it should do a redirect or a forward to another internal resource (e.g. a JSP, tipically).
    Fourth (not less important), since the form is submitted in POST, your servlet must handle this request in the doPost, not doGet.
    Andrea, www.andbin.net SCJP 5 (91%) SCWCD 5 (94%)

    Useful links for Java beginners My new project Java Examples on Google Code

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