[英]How to get XML element path using stax/stax2?
I want to get element path while parsing XML using java StAX2 parser. 我想在使用Java StAX2解析器解析XML时获取元素路径。 How to get information about the current element path? 如何获取有关当前元素路径的信息?
<root>
<a><b>x</b></a>
</root>
In this example the path is /root/a/b
. 在此示例中,路径为/root/a/b
。
Keep a stack. 保持堆栈。 Push the element name on START_ELEMENT and pop it on END_ELEMENT. 在START_ELEMENT上推送元素名称,然后在END_ELEMENT上弹出它。
Here's a short example. 这是一个简短的例子。 It does nothing other than print the path of the element being processed. 除了打印要处理的元素的路径外,它什么都不做。
public static void main(String[] args) throws IOException, XMLStreamException {
try (FileInputStream in = new FileInputStream("test.xml")) {
XMLInputFactory factory = XMLInputFactory.newFactory();
XMLStreamReader reader = factory.createXMLStreamReader(in);
LinkedList<String> path = new LinkedList<>();
int next;
while ((next = reader.next()) != XMLStreamConstants.END_DOCUMENT) {
switch (next) {
case XMLStreamConstants.START_ELEMENT:
// push the name of the current element onto the stack
path.addLast(reader.getLocalName());
// print the path with '/' delimiters
System.out.println("Reading /" + String.join("/", path));
break;
case XMLStreamConstants.END_ELEMENT:
// pop the name of the element being closed
path.removeLast();
break;
}
}
}
}
"The chronicler's duty" “编年史家的职责”
try (InputStream in = new ByteArrayInputStream(xml.getBytes())) {
final XMLInputFactory2 factory = (XMLInputFactory2) XMLInputFactory.newInstance();
final XMLStreamReader2 reader = (XMLStreamReader2) factory.createXMLStreamReader(in);
Stack<String> pathStack = new Stack<>();
while (reader.hasNext()) {
reader.next();
if (reader.isStartElement()) {
pathStack.push(reader.getLocalName());
processPath('/' + String.join("/", pathStack));
} else if (reader.isEndElement()) {
pathStack.pop();
}
}
}
InputElementStack
方法2(丑陋):攻击Woodstox的 InputElementStack
Implementing adapter to access InputElementStack
, its protected mCurrElement
and interate parents (this slows down algoritm). 实现适配器以访问InputElementStack
,其受保护的mCurrElement
和内部父代(这会减慢算法速度)。
package com.ctc.wstx.sr; import java.util.LinkedList; public class StackUglyAdapter { public static String PATH_SEPARATOR = "/"; private InputElementStack stack; public StackUglyAdapter(InputElementStack stack) { this.stack = stack; } public String getCurrElementLocalName() { return this.stack.mCurrElement.mLocalName; } public String getCurrElementPath() { LinkedList<String> list = new LinkedList<String>(); Element el = this.stack.mCurrElement; while (el != null) { list.addFirst(el.mLocalName); el = el.mParent; } return PATH_SEPARATOR+String.join(PATH_SEPARATOR,list); } }
example of use: 使用示例:
try (final InputStream in = new ByteArrayInputStream(xml.getBytes())) { final XMLInputFactory2 factory = (XMLInputFactory2) XMLInputFactory.newInstance(); final XMLStreamReader2 reader = (XMLStreamReader2) factory.createXMLStreamReader(in); final StackUglyAdapter stackAdapter = new StackUglyAdapter(((StreamReaderImpl) reader).getInputElementStack()); while (reader.hasNext()) { reader.next(); if (reader.isStartElement()) { processPath(stackAdapter.getCurrElementPath()); } } }
Method 1 with dedicated stack is better, because is API implementation-independent and is just as fast as the Method 2 . 具有专用堆栈的方法1更好,因为它与API实现无关,并且与方法2一样快。
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