我有一个带有元素（名为region）的XML文档，该元素可能有也可能没有多个子元素。对于我的导入，我需要确保只有一个子元素。如果有更多的子元素，我需要删除除最后一个之外的所有子元素。可能发生以下情况：
// Option 1: No child elements
<property name="region">
</property>
// Option 2: One child element
<property name="region">
<value>Bottom</value>
</property>
// Option 3: Two child elements
<property name="region">
<value>Top</value>
<value>Bottom</value>
</property>
// Option 4: Three child elements
<property name="region">
<value>Top</value>
<value>Middle</value>
<value>Bottom</value>
</property>
我需要的是过滤XML以重新格式化region元素的子元素，使其始终具有一个子元素（value），其中ether是最后一个子元素的值，或者是否有没有孩子，价值'无'。
我想要的输出如下：
// For Option 1
<property name="region">
<value>none</value>
</property>
// For option 2, 3 & 4
<property name="region">
<value>Bottom</value>
</property>
我知道我可以使用xPath查询region选择//property[@name = "region"]属性，但我不知道如何从那里操纵子项。
我遇到以下代码
<?php
$xml = '<properties>
<property name="region">
</property>
<property name="region">
<value>Bottom</value>
</property>
<property name="region">
<value>Top</value>
<value>Bottom</value>
</property>
<property name="region">
<value>Top</value>
<value>Middle</value>
<value>Bottom</value>
</property>
</properties>';
$document = new DOMDocument();
$document->loadXML($xml);
$xpath = new DOMXpath($document);
foreach($xpath->query('//property[@name = "region"]') as $node){
// Now i need something like below, but i can't find a way to make it work
if $node->hasChildren()
Remove all but last child
else
Create child element with text none
}
我希望有人能指出我正确的方向
答案 0 :(得分：0)
您可以使用扭曲的嵌套for循环与getElementByTagName()类的DOMElement一起使用。方法如下：
<?php
$xml = '<properties>
<property name="region">
</property>
<property name="region">
<value>Bottom</value>
</property>
<property name="region">
<value>Top</value>
<value>Bottom</value>
</property>
<property name="region">
<value>Top</value>
<value>Middle</value>
<value>Bottom</value>
</property>
</properties>';
$document = new DOMDocument();
$document->loadXML($xml);
$xpath = new DOMXpath($document);
foreach($xpath->query('//property[@name = "region"]') as $node){
/**@var DOMElement $node*/
// CHECK IF THE $node HAS CHILD NODES USING $node->getElementsByTagName("value")->length PROPERTY
// WHICH RETURNS THE NUMBER OF CHILD NODES
$numChildNodes = $node->getElementsByTagName("value")->length;
// IF THE CURRENT NODE HAS AT LEAST 1 CHILD, LOOP THROUGH THE CHILDREN
// AND REMOVE THE CHILD NODES...EXCEPT FOR THE LAST CHILD NODE...
if($numChildNodes > 0){
$cuePoint = ($numChildNodes - 1);
// LOOP THROUGH ALL CHILD-NODES OF THE CURRENT NODE AND REMOVE ALL CHILD NODES
// EXCEPT FOR THE LAST CHILD NODE...
for($index=0; $index<$numChildNodes; $index++){
if($index !== $cuePoint ) {
$currentNode = $node->getElementsByTagName("value")->item($index);
// REMOVE THIS NODE...
$node->removeChild($currentNode);
}
}
}else{
// IF THE CURRENT NODE HAS NO CHILD AT ALL,
// SIMPLY CREATE AN ELEMENT NODE AND APPEND IT IN THE RIGHT CONTEXT...
// HERE WE ARE USING none AS DEFAULT BUT YOU CAN USE WHATEVER
// STRING YOU PLEASE ...
$newElementNode = new DOMElement("value", "none", "");
$node->appendChild($newElementNode);
}
}
$document->save("abc.xml");
var_dump($document);
abc.xml 文件应该类似于：
<?xml version="1.0"?>
<properties>
<property name="region">
<value>none</value>
</property>
<property name="region">
<value>Bottom</value>
</property>
<property name="region">
<value>Bottom</value>
</property>
<property name="region">
<value>Bottom</value>
</property>
</properties>
虽然var_dump($document);的结果应该产生类似于此的内容：
object(DOMDocument)[1]
public 'doctype' => null
public 'implementation' => string '(object value omitted)' (length=22)
public 'documentElement' => string '(object value omitted)' (length=22)
public 'actualEncoding' => null
public 'encoding' => null
public 'xmlEncoding' => null
public 'standalone' => boolean true
public 'xmlStandalone' => boolean true
public 'version' => string '1.0' (length=3)
public 'xmlVersion' => string '1.0' (length=3)
public 'strictErrorChecking' => boolean true
public 'documentURI' => string '/Applications/MAMP/htdocs/poiz/so/' (length=34)
public 'config' => null
public 'formatOutput' => boolean false
public 'validateOnParse' => boolean false
public 'resolveExternals' => boolean false
public 'preserveWhiteSpace' => boolean true
public 'recover' => boolean false
public 'substituteEntities' => boolean false
public 'nodeName' => string '#document' (length=9)
public 'nodeValue' => null
public 'nodeType' => int 9
public 'parentNode' => null
public 'childNodes' => string '(object value omitted)' (length=22)
public 'firstChild' => string '(object value omitted)' (length=22)
public 'lastChild' => string '(object value omitted)' (length=22)
public 'previousSibling' => null
public 'attributes' => null
public 'ownerDocument' => null
public 'namespaceURI' => null
public 'prefix' => string '' (length=0)
public 'localName' => null
public 'baseURI' => string '/Applications/MAMP/htdocs/poiz/so/' (length=34)
public 'textContent' => string '
none
Bottom
Bottom
Bottom
' (length=146)
希望这可以让你了解如何自己做到最好。
干杯和祝你好运!!!
答案 1 :(得分：0)
每个节点都有一个名为childNodes的属性，该属性具有length属性，这意味着您可以通过这种方式拥有当前节点的子节点数。但由于空格本身被视为单个节点，因此您应该初始化另一个查询并从childNodes->length中减去它们。
这个解决方案是正确的，但不是最好的，因为我们可以缩短它：
$xpath->query('./*', $node)->length > 1
这意味着当前节点中的所有元素节点（不是空格）。在找到具有多个元素子元素的元素之后，我们差不多完成了：
./*[position() < last()]
这意味着当前节点中位置小于最后一个的所有子节点。之后我们可以轻松删除它们。这是您修改后的foreach循环：
foreach ($query as $node){
if ($xpath->query('./*', $node)->length > 1) {
$children = $xpath->query('./*[position() < last()]', $node);
foreach ($children as $child) {
$child->parentNode->removeChild($child);
}
}
}
您可以通过保存修改来确认输出：
echo $document->saveXML();