CODEWITHSUNDEEP
javaservlets
Nane Petrosyan
Nane Petrosyan

Reputation: 613

send alert to html page from servlet

I am trying to create a registration page using java servlet. How can i notify about empty fields in form on my html page? here is a part of my code 

       String uName = request.getParameter("username");
       String pass = request.getParameter("passwd");
       String rpass = request.getParameter("rpasswd");
       String email = request.getParameter("email");
       if(uName == "" || pass == "" || rpass == "" || email == "") {
         //what must i put here to send notification to html page
       }

Upvotes: 0

Views: 824

Answers (2)

Birhan Nega
Birhan Nega

Reputation: 681

   String uName = request.getParameter("username");
   String pass = request.getParameter("passwd");
   String rpass = request.getParameter("rpasswd");
   String email = request.getParameter("email");
    HttpSession session=request.getSession()
   if(uName == null|| pass == null || rpass == null || email == null) {
   //Here you can set session attribute like any error message
   session.setAttribute("error", "Please fill all fields in form");
    request.getRequestDispatcher("yourPage.jsp").forward(request,response);

Then add this line of code in your jspPage

<p>${error}</p>

finally don't forget to unset session

session.setAttribute('error','');

Upvotes: 0

Swati
Swati

Reputation: 28522

You can do that using request.getAttribute() & request.setAttribute() , for eg :

 String uName = request.getParameter("username");
       String pass = request.getParameter("passwd");
       String rpass = request.getParameter("rpasswd");
       String email = request.getParameter("email");
       if(uName == null|| pass == null || rpass == null || email == null) {
       //here you can set attribute like any error message
       request.setAttribute("error", "Please fill all fields in form");
        request.getRequestDispatcher("yourjsppage").forward(request,response); 
       }

And to show above message do like below in jsp page :

//this line will print whatever is in error :  Please fill all fields in form
<p class="text-center" style="color: green">${error}</p>

Alternative way to do validation in form ,you can use required attribute like below :

<form  method="post" action=""> 

 <label for="userid">Name:</label>  
   <input type="text" name="username" required  /><br/>
<label for="passid">Email:</label> 
<input type="text" name="email"  required /> 
<br/>
<input type="submit"  value="Signup"/>

</form>

Hope this helps !

Upvotes: 2

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