How to add 30 days in a timestamp in jstl

问题

I need to add 30 days to the current system date in timestamp. How can I acheive that? I am having below code:

<%

    Date date= new Date();
    long time = date.getTime();
    Timestamp ts = new Timestamp(time);
     %> 
    <c:set var="currentDate"><%=ts%></c:set>
    <c:if test="${startDate lt currentDate}">
        <c:if test="${endDate gt currentDate}">

How can I make ts+ 30? Thanks in advance.

回答1:

Use calendar:

Calendar cal=new GregorianCalendar();
cal.add(Calendar.DATE, 30);
Date d=cal.getTime();

回答2:

<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> 
<%
 Date date= new Date();
 Calendar cal = Calendar.getInstance();
 cal.setTime (date);
 cal.add (Calendar.DATE, 30);
 date = cal.getTime ();
%>
<c:set var="currentDate"><%=date%></c:set>
<c:out value="currentDate"/>

来源：https://stackoverflow.com/questions/28374791/how-to-add-30-days-in-a-timestamp-in-jstl