In my last project, I forgot to judge the list’s size before loop it. So I got an Exception. Then I googled the following solutions.
1. To know if it’s empty:
<s:if test="%{productList.isEmpty()}"> //if the list is empty </s:if> <s:else> <s:iterator value="productList"> //if not empty, then do the loop </s:iterator> </s:else>
2. To know its size
<s:if test="%{productList.size() > 0}">
//do the loop
</s:if>