jstl循环访问对象中的列表

Question

public class NodeRel {
    private String fromNodeId;
    private String toNodeId;
    private String fromNodeName;
    private String toNodeName;
    private List<QuotaValueOnTime> fromNodeSend;
    private List<QuotaValueOnTime> toNodeSend;

    //getters and setters omitted 
}

<div class="table-responsive">
<table class="table table-striped table-bordered table-hover">
    <thead>
        <tr>
            <th class="center">Count</th>
            <th>relation</th>
            <th colspan='25'>Detail</th>
        </tr>
    </thead>

    <tbody>
        <c:forEach var="nodeRel" items="${nodeRelInfo}" varStatus="stc">
            <tr>
                <td rowspan="3">${stc.count}</td>
                <td rowspan="3">${nodeRel.fromNodeName} --> ${nodeRel.toNodeName}</td>
                <td>\</td>
                <c:forEach var="x" begin="0" end="23" step="1"> 
                            <td>${x}</td>
                </c:forEach>
            </tr>
            <tr>
                <td>Send_A</td>
                <c:forEach var="node" items="${nodeRelInfo.fromNodeSend}"> 
                            <td>${node.sumval}</td>
                </c:forEach>

            </tr>
            <tr>
                <td>Send_B</td>
                <c:forEach var="x" begin="0" end="23" step="1"> 
                            <td>${x}</td>
                </c:forEach>
            </tr>
        </c:forEach>
    </tbody>
</table>
</div>

我的代码不能工作，我在第二个循环附近得到了java.lang.NumberFormatException：输入字符串：“FromNodeSend”：

<c:forEach var="node" items="${nodeRelInfo.fromNodeSend}"> 
    <td>${node.sumval}</td>
</c:forEach>

我的代码出了什么问题？

Answer 1

请注意，变量${nodeRelInfo}表示列表，变量${nodeRel}表示您使用的每个项。

因此，您希望在第二个循环中循环的项是${noderelinfo.fromnodesend}。更改变量looped的第二个名称：

<c:forEach var="node" items="${nodeRel.fromNodeSend}"> 
    <td>${node.sumval}</td>
</c:forEach>

它在与Java for-each循环相同的逻辑上工作。

for (List nodeRel: nodeRelInfo) {
    // bla blaa
    for (String node: nodeRel.fromNodeSend()) {
        System.out.println(node);
    }
}