如何使用 XPath 按 TextContent 过滤元素?通过轴获取父级? [英] How to use XPath to filter elements by TextContent? get parent by axis?

问题描述

我发现 关于 SO 的类似问题，但是，似乎不是我想要实现的目标:

I've found a similar question on SO, however, that seems not exactly what I wanna achieve:

比如说，这是一个示例 XML 文件:

Say, this is a sample XML file:

<root>
    <item>
        <id isInStock="true">10001</id>
        <category>Loose Balloon</category>
    </item>
    <item>
        <id isInStock="true">10001</id>
        <category>Bouquet Balloon</category>
    </item>
    <item>
        <id isInStock="true">10001</id>
        <category>Loose Balloon</category>
    </item>
</root>

如果我想得到一个过滤的"此 XML 中 item 元素的子集，我如何使用 XPath 表达式直接解决该问题?

If I wanna get a "filtered" subset of the item elements from this XML, how could I use an XPath expression to directly address that?

XPathExpression expr = xpath.compile("/root/item/category/text()");

我现在知道这将评估为类别中所有 TextContent 的集合，但是，这意味着我必须使用集合来存储值，然后迭代，然后返回获取其他相关信息，例如再次输入项目 ID.

I now know this would evaluate to be the collection of all the TextContent from the categories, however, that means I have to use a collection to store the values, then iterate, then go back to grab other related info such as the item id again.

另一个问题是:如何正确引用父节点?

Another question is : how could I refer to the parent node properly?

比如说，这个 xpath 表达式会让我得到所有 id 节点的集合，对吗?但我想要的是项目节点的集合:

Say, this xpath expression would get me the collection of all the id nodes, right? But what I want is the collection of item nodes:

XPathExpression expr = xpath.compile("/root/item/id[@isInStock='true']");

我知道我应该使用父级"轴来指代那个，但我就是做对了...

I know I should use the "parent" axis to refer to that, but I just cannot make it right...

有没有更好的方法来做这种事情?现在学习 w3cschools 教程...

Is there a better way of doing this sort of thing? Learning the w3cschools tutorials now...

抱歉，我是 Java 中的 XPath 新手，在此先感谢您.

Sorry I am new to XPath in Java, and thanks a lot in advance.

推荐答案

如果我想得到一个过滤"的子集这个 XML 中的 item 元素，如何我可以使用 XPath 表达式吗直接解决那个?

If I wanna get a "filtered" subset of the item elements from this XML, how could I use an XPath expression to directly address that?

一个示例 XPath 表达式:

An example XPath expression:

/*/item[id/@isInStock='true']/category/text()

此 XPath 表达式选择 isInStock 属性的所有 元素的所有 元素的所有文本节点子节点其中 id 子元素的值为 'true' 并且(id 元素)是 XML 文档顶部元素的子元素.

This XPath expression selects all text-node children of all <category> elements of all <item> elements the isInStock attribute of whose id child has a value of 'true' and (the id elements) that are children of the top element of the XML document.

另一个问题是:我怎么能正确引用父节点?

Another question is : how could I refer to the parent node properly?

使用:

parent::node()

或者干脆

..

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