XPATH执行复杂的查询

Question

如何在给定的xml上执行以下查询：

1. 如果（task1 = cde && task2 = abc）我会得到id = XYZ-987
2. 如果（（task1 = abc && task2 = efg）|| task5 = nop）我会得到id = ABC-123，XYZ-987，RST-567

XML在这里：

<node1>
<node2>
    <node3>
        <id>ABC-123</id>
        <condition>
            <task name="task1" operation="and" value="abc" />
            <task name="task2" operation="and" value="efg" />
            <task name="task3" operation="and" value="hij" />
            <task name="task4" operation="or" value="klm" />
            <task name="task5" operation="and" value="nop" />
            <task name="task6" value="uvw" />
        </condition>
    </node3>
    <node3>
        <id>XYZ-987</id>
        <condition>
            <task name="task1" operation="and" value="cde" />
            <task name="task2" operation="and" value="abc" />
            <task name="task5" operation="and" value="nop" />
        </condition>
    </node3>
    <node3>
        <id>RST-567</id>
        <condition>
            <task name="task1" operation="and" value="abc" />
            <task name="task2" operation="and" value="efg" />
            <task name="task8" operation="and" value="jkl" />
            <task name="task9" operation="and" value="rst" />
            <task name="task10" value="xyz" />
        </condition>
    </node3>
    <node3>
        <id>PQR-345</id>
        <condition>
            <task name="task1" operation="and" value="ijk" />
            <task name="task2" operation="and" value="klm" />
            <task name="task8" operation="and" value="jkl" />
            <task name="task9" operation="and" value="rst" />
        </condition>
    </node3>
</node2>
</node1>    

我尝试了以下规则，但结果为空

String expression = "/node1/node2/node3/id[following-sibling::condition/task[(@name='task1' and @value='cde') and (@name='task2' and @value='abc')]]"

我从如何使用XPATH解析XML中获得了上述表达式

以上两种情况的表达是什么？

Answer 1

您的xpath不起作用的原因是因为您的谓词[(@name='task1' and @value='cde') and (@name='task2' and @value='abc')]在同一位置执行任务节点，如果@name = 'task1'则@name永远不会是'task2' 。

相反，您应该创建谓词，该谓词将在所有相关节点上运行/检查，如下所示：

1。

如果（task1 = cde && task2 = abc）我会得到id = XYZ-987

/node1/node2/node3[condition/task[@name='task1' and @value='cde'] and condition/task[@name='task2' and @value='abc']]/id

2。

如果（（task1 = abc && task2 = efg）|| task5 = nop）我会得到id = ABC-123，XYZ-987，RST-567

/node1/node2/node3[condition/task[@name='task1' and @value='abc'] and condition/task[@name='task2' and @value='efg'] or condition/task[@name='task5' and @value='nop']]/id

你可以包括你的括号，如果你想要的，但在布尔运算， and参数总是之前评估or论证，所以他们在这种情况下没有必要： /node1/node2/node3[(condition/task[@name='task1' and @value='abc'] and condition/task[@name='task2' and @value='efg']) or condition/task[@name='task5' and @value='nop']]/id