duplicating local variable in a jsp

Question

I'm having a weird error when reloading my index.jsp page in a java web project.

<% 
    // index.jsp
    // imports
    String teams = Init.getTeams();
%>

<!-- default html content -->
<select class="select">
   <option value="0" selected="selected">Choose Home Team</option>
   <%= teams %>
</select>
<!-- default html content -->

So I'm calling Init.getTeams() from this java method:

public static String getTeams() {
        String s = "";

        ArrayList<Team> teams = new ArrayList<Team>();
        teams = MySQLConnection.getTeams();

        for (Team t : teams) {
            s += "<option value='" + t.getId() + "'>" + t.getName() + "</option>";
        }

        return s;
    }

(Connects to a MySQLConnection class that I've written to retrieve the values from the database). And it'll return something like this:

<option value='1'>Royals</option>
<option value='2'>Red Sox</option>
<option value='3'>Athletics</option>
<option value='4'>Tigers</option>
<option value='5'>Rays</option>
<option value='6'>Angels</option>

... and correctly populate the select box. The problem is that when I reload the page, it duplicates the string that is returned and all the <option>s are duplicated. Why is this happening?

Edit: Probably worth noting I'm running apache tomcat server, and when restarted, it resets and is displayed 1 time the first time the page is brought up, 2 times on the second time, etc. I've also tried to use meta tags to not cache the page, as that's what I suspected was happening - with no luck.

score 1 · Accepted Answer · answered Apr 30 '14 at 03:35

1

I fixed this by putting <%! at the very beginning of the index.jsp page, replacing the <%. I still don't understand exactly why this worked, but it did.

answered Apr 30 '14 at 03:35

ncf

556
4
16

<% is a scriptlet, <%! is a declaration. See also https://stackoverflow.com/a/11486708. – dfrankow Oct 06 '22 at 21:02

TSB99X · Answer 2 · 2014-04-30T08:01:09.923

0

Small suggestion: do use JSTL core tag lib for each, if you can of course. It will do code more simple and obvious, less error-prone. You even not need to implement getTeams method, as accessors used strait forward.

/* Somewhere in declarations part */
<%@taglib prefix="core_rt" uri="http://java.sun.com/jstl/core_rt"%>

...

/* inside select block */
<option value="0" selected="selected">Choose Home Team</option>
<core_rt:forEach items="${teams}" var="team">
   <option value="${team.getId()}">${team.getName}</option>
</core_rt:forEach>

edited Apr 30 '14 at 08:01

answered Apr 30 '14 at 03:49

TSB99X

3,260
2
18
20

I'll look into doing it this way. Thanks! – ncf Apr 30 '14 at 03:51

duplicating local variable in a jsp

2 Answers2