xml 使用 xpath 删除节点
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Remove a node using xpath
提问by rgamber
I have an xml structure as follows:
我有一个 xml 结构如下：
<a>
<b>
<foo>null</foo>
</b>
<b>
<foo>abc</foo>
</b>
<b>
<foo>efg</foo>
</b>
</a>
I am using org.w3c.dom.Documentto update the nodes. when <foo>has a value null, I want to remove
我正在使用org.w3c.dom.Document更新节点。当<foo>有值时null，我想删除
<b>
<foo>null</foo>
</b>
Is this possible? I know I can call removeChild(childElement), but not sure how I can specify to remove the specific nested element above.
这可能吗？我知道我可以调用removeChild(childElement)，但不确定如何指定删除上面的特定嵌套元素。
Update:With the answer below, I tried:
更新：根据下面的答案，我尝试过：
String query = "/a/b[foo[text() = 'null']]";
Object result = (xpath.compile(newQuery)).evaluate(doc, NODE);
NodeList nodes = (NodeList)result;
for (int i = 0; i < nodes.getLength(); i++)
{
Node node = nodes.item(i);
doc.removeChild(node);
}
I get NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist.
我明白了NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist。
回答by Ian Roberts
doc.removeChild(node);
will not work because the node you're trying to remove isn't a child of the document node, it's a child of the document element(the a), which itself is a child of the document root node. You need to call removeChildon the correct parent node:
将不起作用，因为您尝试删除的节点不是文档节点的子节点，而是文档元素(the a)的子节点，而文档元素本身是文档根节点的子节点。您需要调用removeChild正确的父节点：
node.getParentNode().removeChild(node);
回答by Kirill Polishchuk
To get that node you can use XPath:
要获取该节点，您可以使用 XPath：
/a/b[foo[text() = 'null']]
