java - XPath 解析特定节点

Question

我需要通过匹配“Ref Location=”C1”和“EventData ID=”W12”的索引来获取“ItemKey=”X””值。如果您注意到，所有四个都有“Ref Location=”C1”，但只有最后 3 个具有“EventData ID=”W12”'

<Object>
<Level1>
    <Level2>
        <Ref Location="C1"/>
        <EventData ID="W6" EventKey="1">
            <FormData ID="NL">
                <ItemData ItemID="LINE" ItemKey="1">...</ItemData>
            </FormData>
        </EventData>
    </Level2>
</Level1>
<Level1>
    <Level2>
        <Ref Location="C1"/>
        <EventData ID="W12" EventKey="1">
            <FormData ID="NL">
                <ItemData ItemID="LINE" ItemKey="1">...</ItemData>
            </FormData>
        </EventData>
    </Level2>
</Level1>
<Level1>
    <Level2>
        <Ref Location="C1"/>
        <EventData ID="W12" EventKey="1">
            <FormData ID="NL">
                <ItemData ItemID="LINE" ItemKey="2">...</ItemData>
            </FormData>
        </EventData>
    </Level2>
</Level1>
<Level1>
    <Level2>
        <Ref Location="C1"/>
        <EventData ID="W12" EventKey="1">
            <FormData ID="NL">
                <ItemData ItemID="LINE" ItemKey="3">...</ItemData>
            </FormData>
        </EventData>
    </Level2>
</Level1>

目前我有

(/Object/Level1/Level2/Ref[@Location='C1'])[2]/../EventData[@ID='W12']/FormData/ItemData/@ItemKey

其中 X 是索引，但它为所有“C1”节点获取 ItemKey="X"。我只需要为 ID="W12"节点获取 ItemKey="X"。

当路径具有“[X]”时的期望结果

[1] -> ItemKey="1"    // ID = "W12"
[2] -> ItemKey="2"    // ID = "W12"
[3] -> ItemKey="3"    // ID = "W12"

Answer 1

这应该有效:

//ItemData[preceding::Ref[1][@Location="C1"][following-sibling::EventData[@ID="W12"]]]/@ItemKey

输出:3 个值:

1
2
3