如何在标签内更新值

I have list which contains some objects. The objects have an hours field.

我有一个包含一些对象的列表。对象有一个小时字段。

In the <c:foreach> I am iterating the list and fetching the objects.

在中，我遍历列表并获取对象。

Now I want to sum up the hours field of all the iterated objects in a totalHours variable.

现在我要总结一下totalHours变量中所有迭代对象的时域。

My code:

我的代码:

<c:forEach var="attendance" items="${list }" varStatus="rowCounter1">
  <tr>
    <td><c:out value="${rowCounter1.count}"></c:out></td>
    <td><c:out value="${attendance.date }"></c:out></td>
    <td><c:out value="${attendance.inTime }"></c:out></td>
    <td><c:out value="${attendance.outTime }"></c:out></td>
    <td><c:out value="${attendance.interval }"></c:out></td>

    <c:set var="totalHours" value="${attendance.Hours += attendance.Hours }"
           target="${attendance}"</c:set>                                       
  </tr>
</c:forEach>

I was trying this, but it gave me the following error:

我尝试了这个，但是它给了我以下的错误:

javax.el.ELException: Failed to parse the expression [${attendance.Hours += attendance.Hours }

1 个解决方案

#1

In Java, it would look like this:

在Java中，它是这样的:

// before the loop:
int totalHours = 0;
for (Attendance attendance : list) {
    totalHours = totalHours + attendance.getHours();
}

So do the same in JSTL:

在JSTL中也一样:

<c:set var="totalHours" value="${0}"/>
<c:forEach var="attendance" items="${list }" varStatus="rowCounter1">
    ...
    <c:set var="totalHours" value="${totalHours + attendance.hours}"/>
</c:forEach>

#1