JSTL和EL表达式诡异的问题
以下代码昨天之前一直都正常，代码也未经任何修改，今天开始突然就一直报JSP编译错误，具体是因NumberFormatException导致的编译不过去，我实在懵了，报NumberFormat的地方明明是字符串，怎么它就非要给我转换成数字呢？百思不得其解，特来请假CSDN上的高人
代码如下：

<%@ page language="java"  pageEncoding="utf-8"%>

<%@ page import="java.util.List" %>

<%@ page import="java.util.ArrayList" %>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>



<div class="topic">



	<div class="floor">

		<div class="title">

			<h1>

				${topic.title}

			</h1>

		</div>

		<div class="floormsg title">

			<span class="spt">楼主：<a class="author" href="">${topic.username}</a> </span>

			<span class="spt">发表于${topic.pubtime}</span>

			<span class="spt">点击：</span>

			<span class="red">${viewcount}</span>

			<span class="spt">回复：</span>

			<span class="red">${replycount}</span>

			<span class="spt">

				<button id="onlyowner" class="btn">

					只看楼主

				</button> </span>

            <span class="spt">

            <button id="readsettingbtn" class="btn">

                阅读设置

            </button> </span>

		</div>

     <c:if test="${currentpage==1}">

		<div class="contentdiv">

		  ${topic["content"]}

		</div>

     </c:if>

	</div>



	<c:forEach items="${replyList}" var="reply" varStatus="replyStatus">

		<div class="floor">

			<div class="floormsg">

				<span>作者：<a class="author" href="">${reply.username}</a> </span>

				<span class="index"> ${replyStatus.index+startfloor}楼</span>

				<span class="pubt">发表于${reply.pubtime}</span>

			</div>

			<div class="contentdiv">

				${reply["content"]}

			</div>

			<div class="operate">

				<a href="" onclick="">引用</a>

				<a href="" onclick="">举报</a>

			</div>

		</div>

	</c:forEach>

</div>

org.apache.jasper.JasperException: An exception occurred processing JSP page /bbs/topic/floor.jsp at line 40

37:  <c:forEach items="${replyList}" var="reply" varStatus="replyStatus">
38:  <div class="floor">
39:  <div class="floormsg">
40:  <span>浣滆?锛?a class="author" href="">${reply.username}</a> </span>
41:  <span class="index"> ${replyStatus.index+startfloor}妤?/span>
42:  <span class="pubt">鍙戣〃浜?{reply.pubtime}</span>
43:  </div>



关于s1+= 一和s1=s1+1的区别