removeChild()方法正在中断循环 [英] removeChild() method is breaking for loop

问题描述

我正在使用以下代码从XMl文件中删除多个元素.

I am using following code to remove multiple elements from XMl file.

NodeList removeNodeList = doc.getElementsByTagName("server1");
Element rootElement = doc.getDocumentElement();

for (int i = 0; i < removeNodeList.getLength(); i++) {
    rootElement.removeChild(removeNodeList.item(i));
}

但是删除一个元素后，它就退出了循环.有什么问题.

But after removing one element it is coming out of loop. What is the issue.

以下是我的XML文件内容.

Following is my XML file content.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<start>

    <category name="server1"/>
    <category name="server2"/>

    <server1 name="serverName1" value="serverValue"/>
    <server1 name="serverName1" value="serverValue"/>

    <server2 name="serverName2" value="serverValue"/>

</start>

推荐答案

我找到了解决方法:

让我详细解释问题所在.

Let me explain what was the problem in detail.

NodeList removeNodeList = doc.getElementsByTagName("server1"); removeNodeList.getLength()将返回2，因为有2个节点的节点名称为server1，然后在执行rootElement.removeChild(removeNodeList.item(i));然后检查for loop条件i.e.后，i的值为1，而removeNodeList.getLength()返回1因为现在只有1个节点名称为server1的节点保留在DOM document中，并且此情况由于1 < 1 is false

NodeList removeNodeList = doc.getElementsByTagName("server1"); removeNodeList.getLength() will return 2 as there are 2 nodes with nodeName server1 then after executing rootElement.removeChild(removeNodeList.item(i)); and then checking for loop condition i.e. the value of i is 1 and removeNodeList.getLength() returns 1 as now only 1 node with nodeName server1 is remaining in DOM document and this condition was failing as 1 < 1 is false

所以我遵循以下方法:

一旦不再使用NodeList，请删除所有元素.

Delete all the elements afterwards once the NodeList is no longer used.

NodeList nodes = doc.getElementsByTagName(elementName);
Set<Element> targetElements = new HashSet<Element>();

for (int i = 0; i < nodes.getLength(); i++) {
    Element e = (Element)nodes.item(i);
    targetElements.add(e);
}
for (Element e: targetElements) {
    e.getParentNode().removeChild(e);
}

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