java 为什么我不能删除刚刚找到的子元素？NOT_FOUND_ERR
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Why can I not remove a child element I've just found? NOT_FOUND_ERR
提问by dhardy
I'm building a script which has to patch XML files, including replacing one list of elements with another. The following function applies a patch (involving a possibly empty list of elements with the same name) onto a parent Element's list of elements by the same name (also possibly an empty list). (This is only a small part of the patching logic).
我正在构建一个必须修补 XML 文件的脚本，包括将一个元素列表替换为另一个。以下函数将补丁（涉及可能为空的同名元素列表）应用于父元素的同名元素列表（也可能是空列表）。（这只是补丁逻辑的一小部分）。
Why, when I run the code, do I get the following error?
为什么，当我运行代码时，会出现以下错误？
org.w3c.dom.DOMException: NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist.
at com.sun.org.apache.xerces.internal.dom.ParentNode.internalRemoveChild(ParentNode.java:503)
at com.sun.org.apache.xerces.internal.dom.ParentNode.removeChild(ParentNode.java:484)
at CombineSweeps$PTReplaceNodeList.apply(CombineSweeps.java:514)
(Line 514 is labelled below.) As far as I understand it, I've just verified that the element exists (because NodeList is live, its first entry will always be the next match or null). Interestingly, this isn't always a problem.
（第 514 行标记如下。）据我所知，我刚刚验证了该元素是否存在（因为 NodeList 是活动的，它的第一个条目将始终是下一个匹配项或为空）。有趣的是，这并不总是一个问题。
private static class PTReplaceNodeList extends PTBase {
private final String name;
private final String nextElement;
private final List<Node> childList;
...
int apply(Document document, Node parent, Node node_unused) {
NodeList nodes;
// A marker for where to insert our nodes.
// We make a guess using nextElement (if null, means at end).
Node refNode = null;
if (parent instanceof Document) { // root element
Document parDoc = (Document) parent;
nodes = parDoc.getElementsByTagName(name);
if (nextElement != null) {
refNode = parDoc.getElementsByTagName(nextElement).item(0);
}
} else {
Element parElt = (Element) parent;
nodes = parElt.getElementsByTagName(name);
if (nextElement != null) {
refNode = parElt.getElementsByTagName(nextElement).item(0);
}
}
while (true) {
// iterate through the list of nodes
Node node = nodes.item(0);
if (node == null) {
break;
}
// Reliable guess: insert before node following last in list
refNode = node.getNextSibling();
parent.removeChild(node); // line 514
}
for (Node child : childList) {
Node imported = document.importNode(child, true);
parent.insertBefore(imported, refNode);
}
return childList.size();
}
}
Edit: I used the following function as a replacement for getElementsByTagName()(see accepted answer).
编辑：我使用以下函数代替getElementsByTagName()（见接受的答案）。
/** Returns all direct children of node with name name.
*
* Note: not the same as getElementsByTagName(), which finds all descendants. */
static List<Node> getChildNodes( Node node, String name ){
ArrayList<Node> r = new ArrayList<Node>();
NodeList children = node.getChildNodes();
int l = children.getLength();
for( int i = 0; i < l; ++i ){
if( name.equals( children.item(i).getNodeName() ) )
r.add( children.item(i) );
}
return r;
}
采纳答案by Maurice Perry
This is because when you are doing parent.removeChild(node), parent is not necessarily the parent of the node because getElementsByTagName() is doing a recursive search.
这是因为在执行 parent.removeChild(node) 时，parent 不一定是节点的父节点，因为 getElementsByTagName() 正在执行递归搜索。
回答by Kalpesh Soni
how about
怎么样
nodeToBeRemoved.getParentNode().removeChild(nodeToBeRemoved);
回答by dogbane
parent.removeChild(node)is throwing a NOT_FOUND_ERR because nodeis not a child of parent. I see that nodecomes from getElementsByTagNamewhich might not be an immediate child of parent. It could be anywhere under parent.
parent.removeChild(node)正在抛出 NOT_FOUND_ERR 因为node不是parent. 我看到node来自getElementsByTagName这可能不是一个立即的孩子parent。它可以在parent.
回答by LarsH
Building on the diagnosis by @Maurice and @fahd...
基于@Maurice 和@fahd 的诊断...
Can't you just put a condition before
你不能在前面加一个条件吗
parent.removeChild(node);
such as
如
if (parent.isSameNode(node.getParentNode()))
Then it would only remove a direct child of the given parent.
然后它只会删除给定父级的直接子级。
