Question

I am creating a simple guest book in JSP in order to learn this technology. Currently I have two classes: guestbook/GuestBook.class and guestbook/Entry.class (I haven’t finished the app yet, so I have only these classes) which are added into WEB-INF/libs/ and they’re included properly. In my file index.jsp I am using guestbook.GuestBook class; its method returns Vector. When I iterate over entries and I’d like to print an author of the entry, I can see:

javax.el.PropertyNotFoundException: Property 'author' not found on type guestbook.Entry

I must add that Entry class is public and author attribute is declared in such way:

public String author;

So it is public, too. This is my code when I iterate over the entries:

<c:forEach items="${entries}" varStatus="i">
  <c:set var="entry" value="${entries[i.index]}" />
  <li><c:out value="${entry.author}" /></li>
</c:forEach>

and

entry.class.name

returns guestbook.Entry

The classes are in package guestbook (as you can guess), entries vector is passed to pageContext.

I do not know what is wrong with my way of doing it. Can anybody help me please with that? (Thanks in advance!)

Answer 1

JSP EL will not recognise public fields in your classes, it only works with getter methods (which is good practice anyway – never expose your classes’ state as public fields like this).

So use

private String author;

public String getAuthor() {
   return author;
}

instead of

public String author;

As a side note, your JSTL is overly complicated, it can be simplified to:

<c:forEach items="${entries}" var="entry">
  <li><c:out value="${entry.author}" /></li>
</c:forEach>

or even

<c:forEach items="${entries}" var="entry">
  <li>${entry.author}</li>
</c:forEach>

although the latter form will not XML-escape the author name, so isn’t advised.

Lastly, the Vector class is obsolete, you should use ArrayList instead.