java JSTL c:forEach，递减数循环不可能？
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JSTL c:forEach, decremental number loop impossible?
提问by shkim
I want to print decremental numbers like:
我想打印递减数字，如：
<c:forEach var="i" begin="10" end="0" step="-1">
... ${i} ...
</c:forEach>
then I got jsp exception:
然后我得到了jsp异常：
javax.servlet.jsp.JspTagException: 'step' <= 0
javax.servlet.jsp.jstl.core.LoopTagSupport.validateStep(LoopTagSupport.java:459)
org.apache.taglibs.standard.tag.rt.core.ForEachTag.setStep(ForEachTag.java:60)
....
but this answer says it is possible to loop in both ways:
但是这个答案说可以以两种方式循环：
What's wrong with me?
我怎么了？
回答by BalusC
I am not sure how the answerer of the other question got it to work, but I can't get it to work here with the reference JSTL implementation.
我不确定另一个问题的回答者是如何让它工作的，但我无法在这里使用参考 JSTL 实现来工作。
Anyway, you can achieve the requirement with following:
无论如何，您可以通过以下方式达到要求：
<c:forEach var="i" begin="0" end="10" step="1">
... ${10 - i} ...
</c:forEach>
Or if you'd like to avoid duplication of 10:
或者，如果您想避免重复10：
<c:forEach var="i" begin="0" end="10" step="1" varStatus="loop">
... ${loop.end - i + loop.begin} ...
</c:forEach>
回答by Giulio Piancastelli
A possible solution, without using the varattribute:
一个可能的解决方案，不使用var属性：
<c:forEach begin="0" end="10" varStatus="loop">
${loop.end - loop.count + 1}
</c:forEach>
Note that stepis omitted too, because its default value is 1.
注意 也step被省略了，因为它的默认值是1。
