how to use condition statements in jsp?

Question

I have a servlet class for login process, if the username or password is incorrect I want to set two attributes to the request, one attribute is boolean authentication_error, the second is string authentication_error_message.

I want to make a condition statement to print the authentication_error_message if the authentication_error is true.

req.setAttribute("authentication_error", false);

if(!query.list().isEmpty()){
    List<?> list = query.list();
    Admin student = (Admin)list.get(0);
    req.setAttribute("username", student.getUsername());
}
else{

    req.setAttribute("authentication_error_message", "username or password is incorrect!");
    req.setAttribute("authentication_error", true);
}

req.getRequestDispatcher("/views/login.jsp").forward(req, res);

How I can write this statement in jsp?

N.B: preferr to not use jstl.

Why not using JSTL ? It's much nicer than mixed Java, HTML and JS — Dici, Jan 25 '16 at 19:50
You could forward to two different jsps, as there are different attributes, Otherwise jstl `` is still the most compact way. — Joop Eggen, Jan 25 '16 at 19:52
@Dici because I already know how to do it with jstl, I just asked for an alternative, thanks! — Mohammad, Jan 25 '16 at 20:16
@Mohammad but there is no *better* alternative, just fo you to know — Dici, Jan 25 '16 at 20:25

score 2 · Accepted Answer · edited May 23 '17 at 11:53

2

Scriptlets are not recommended, JSTL is the way to go for these scenarios. That being said, a different way could be scriptlets.

Scriptlet syntax example:

<%
 String userName="";

if(statement){
 userName=request.getParameter("userName");
  }
%>

See source here Java code inside JSP page.

How to avoid using scriptlets How to avoid using scriptlets in my JSP page?

edited May 23 '17 at 11:53

Community

1
1

answered Jan 25 '16 at 19:51

Perdomoff

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score 0 · Answer 2 · answered Jan 25 '16 at 20:23

You can use scriplet if you don't prefer to use JSTL.

Below code snippet is demonstration on how we can use condition statements in JSP.

<% if("true".equals      (request.getParameter ("authentication_error"))) {
%>
  authentication_error_message
<% }
else {
%>      
   Other Message
<%  } %>

how to use condition statements in jsp?

2 Answers2