如何驗證jsp中的列表是否爲空？

Question

文件名：BillToparty.jsp
問題 - 如果chargelist（BilltoParty）爲空，那麼我們需要顯示一個警報。

<c:forEach items="${chargeList}" var="charge" varStatus="count"> 
<td class="billToParty billingCharge${count.index}"> 
          <c:if test="${not empty charge.arBillToParty}"> 
           <c:choose> 
            <c:when test="${charge.arBillToParty eq 'A'}"> 
             <c:set value="${charge.arBillToParty}" var="Agent"/> 
             <c:set var="agentTotalAmount" value="${agentTotalAmount + charge.rolledupCharges + charge.adjustmentAmount}" /> 
             Agent 
            </c:when> 
            <c:when test="${charge.arBillToParty eq 'F'}"> 
             <c:set value="${charge.arBillToParty}" var="Forwarder"/> 
             <c:set var="forwarderTotalAmount" value="${forwarderTotalAmount + charge.rolledupCharges + charge.adjustmentAmount}" /> 
             Forwarder 
             <input type="hidden" id="fwdValidate" value="${charge.arBillToParty}"> 
            </c:when> 
                    </c:choose> 
          </c:if> 
         </td> 
</c:forEach> 
<input type="button" class="button-style1" value="Post" id="Post" onclick="postcheck();"/> 

文件名：BilltoParty.js 我在這裏驗證

function postcheck() { 
var flag=true; 
    if ($(".billToParty").val() === "") { 
       $.prompt("Please ensure all charge items have a bill to party"); 
       flag = false; 
    } 
} 

Answer 1

可以檢查列表是空喜歡

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> 
    <c:if test="${empty yourList}"> 

做檢查大小的另一種方式。但上述方法簡明易讀

<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %> 
    <c:if test="${fn:length(yourList) > 0}"> 

更新： -看起來像你要檢查它在JavaScript

function postcheck() { 
var flag=true; 
    if ($("billToParty").text().trim()=="") { 
       $.prompt("Please ensure all charge items have a bill to party"); 
       flag = false; 
    } 
}