Java EE在scriptlet中没有文本字段吗？

Question

So I have been wandering around the web for some time looking for this answer. Is there no way of having text fields in java scriptlets for a JSP? I know that in C# you can have

@Html.TextField();

And that will create a text field for you to use as C# code.

Why I would like this, is that I am grabbing a session and checking to see if the user attribute has a user name stored. If it does I don't want it to display the username textbox. Although from what I can tell I can't do that with java scriptlets.

<%if(session.getAttribute("user") == null) %>
Username: <input type="text" name="name"><br/>

Is there something that I am missing?

Answer 1

This will work, but it's better to use JavaServer Pages Standard Tag Library and Expression language
instead of scriptlets. It tend to complicate maintenance for JSP-pages.

You can set a scoped variable on the JSP page. In this manner:

<c:set var="myVariable" scope="page" value="expression"/>

Your situation can be easily solved with the help of JSTL with EL:

<c:if test="${sessionScope.user eq null}">
   <c:out value="Username: ${myVariable}" />
</c:if>

If you have a more complex logic then it makes sense to create a custom tags .