jstl 对list集合进行求和

 

1.情景展示

<table style="order-collapse: collapse;" cellspacing="0" cellpadding="1" border="0" width="99%">
    <tbody>
        <tr class="TableHeader" align="center">
            <td class="TableHeaderCell" nowrap="nowrap">日期</td>
            <td class="TableHeaderCell" nowrap="nowrap">线上正式卡</td>
            <td class="TableHeaderCell" nowrap="nowrap">线上临时卡</td>
            <td class="TableHeaderCell" nowrap="nowrap">线下正式卡</td>
            <td class="TableHeaderCell" nowrap="nowrap">线下临时卡</td>
        </tr>
        <c:forEach var="card" items="${model.data}">
        <tr class="TableRow" align="center">
            <td nowrap="nowrap" class="TableCell" align="left">${card.REGTIME}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${card.ONLINE_FORMAL}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${card.ONLINE_INFORMAL}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${card.OFFLINE_FORMAL}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${card.OFFLINE_INFORMAL}</td>
        </tr>
        </c:forEach>
    </tbody>
</table>　　

　　如上图所示，在使用c:foreach标签迭代完毕后，需要加一行合计，对每列数据进行求和，如何实现？　　 

2.思路分析

　　foreach标签起到Java里for循环的作用；

　　set标签可以用于声明变量或者变量赋值；

　　EL表达式支持各种数值运算和字符串函数。　　 

3.解决方案

<table style="order-collapse: collapse;" cellspacing="0" cellpadding="1" border="0" width="99%">
    <tbody>
        <tr class="TableHeader" align="center">
            <td class="TableHeaderCell" nowrap="nowrap">日期</td>
            <td class="TableHeaderCell" nowrap="nowrap">线上正式卡</td>
            <td class="TableHeaderCell" nowrap="nowrap">线上临时卡</td>
            <td class="TableHeaderCell" nowrap="nowrap">线下正式卡</td>
            <td class="TableHeaderCell" nowrap="nowrap">线下临时卡</td>
        </tr>
        <c:forEach var="card" items="${model.data}">
        <tr class="TableRow" align="center">
            <td nowrap="nowrap" class="TableCell" align="left">${card.REGTIME}</td>
            <td nowrap="nowrap" class="TableCell" align="left">
                ${card.ONLINE_FORMAL}
                <c:set var="SUM_ONLINE_FORMAL" value="${SUM_ONLINE_FORMAL + card.ONLINE_FORMAL}"/>
            </td>
            <td nowrap="nowrap" class="TableCell" align="left">
                ${card.ONLINE_INFORMAL}
                <c:set var="SUM_ONLINE_INFORMAL" value="${SUM_ONLINE_INFORMAL + card.ONLINE_INFORMAL}"/>
            </td>
            <td nowrap="nowrap" class="TableCell" align="left">
                ${card.OFFLINE_FORMAL}
                <c:set var="SUM_OFFLINE_FORMAL" value="${SUM_OFFLINE_FORMAL + card.OFFLINE_FORMAL}"/>
            </td>
            <td nowrap="nowrap" class="TableCell" align="left">
                ${card.OFFLINE_INFORMAL}
                <c:set var="SUM_OFFLINE_INFORMAL" value="${SUM_OFFLINE_INFORMAL + card.OFFLINE_INFORMAL}"/>
            </td>
        </tr>
        </c:forEach>
        <tr class="TableRow" align="center">
            <td nowrap="nowrap" class="TableCell" align="left">合计</td>
            <td nowrap="nowrap" class="TableCell" align="left">${SUM_ONLINE_FORMAL}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${SUM_ONLINE_INFORMAL}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${SUM_OFFLINE_FORMAL}</td>
            <td nowrap="nowrap" class="TableCell" align="left">${SUM_OFFLINE_INFORMAL}</td>
        </tr>
    </tbody>
</table>

　　

写在最后

　　哪位大佬如若发现文章存在纰漏之处或需要补充更多内容，欢迎留言！！！

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