Getting current date in JSTL EL and doing arithmetic on it

问题

Without using scriptlets, what's the correct way for doing date arithmetic in JSP?

Here are examples what I'm trying to do:

1. Get current year (YYYY)
2. Subtract current year by one to get previous year (YYYY)

Thanks!

回答1:

Use <jsp:useBean> to construct new Date. Use JSTL <fmt:formatDate> to get the year out of it. Use EL to substract it.

<%@taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<jsp:useBean id="now" class="java.util.Date" />
<fmt:formatDate var="year" value="${now}" pattern="yyyy" />
<p>Current year: ${year}</p>
<p>Previous year: ${year - 1}</p>

Result:

Current year: 2011

Previous year: 2010

Note that the pattern for full year is yyyy, not YYYY.

来源：https://stackoverflow.com/questions/4949554/getting-current-date-in-jstl-el-and-doing-arithmetic-on-it