如何使用stax/stax 2获取XML元素路径？

Question

我希望在使用java StAX2解析器解析XML时获得元素路径。如何获取有关当前元素路径的信息？

<root>
  <a><b>x</b></a>
</root>

在本例中，路径是/root/a/b。

Answer 1

留一堆。在START_ELEMENT上推送元素名，并在END_ELEMENT上弹出它。

下面是一个简短的例子。它只会打印正在处理的元素的路径。

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;
            }
        }
    }
}

Answer 2

“编年史上的责任”

方法1:专用堆栈@teppic建议

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();
        }
    }
}

方法2(丑陋)：黑客攻击伍德斯托克斯氏 InputElementStack

• 实现适配器来访问InputElementStack、其受保护的mCurrElement和插入父级(这会减慢algoritm)。 包com.ctc.wstx.sr；导入java.util.LinkedList；公共类StackUglyAdapter {公共静态字符串PATH_SEPARATOR = "/"；私有InputElementStack堆栈；公共StackUglyAdapter(InputElementStack堆栈){ this.stack =堆栈；}公共字符串getCurrElementLocalName() {返回this.stack.mCurrElement.mLocalName；}公共字符串getCurrElementPath() { LinkedList列表=新LinkedList()；元素el = this.stack.mCurrElement；时间(el != null) { list.addFirst(el.mLocalName)；el = el.mParent；}返回PATH_SEPARATOR+String.join(PATH_SEPARATOR，list)；}
• 使用实例： 试试看(final InputStream in = new ByteArrayInputStream(xml.getBytes(){ XMLInputFactory2工厂= (XMLInputFactory2) XMLInputFactory.newInstance()；XMLStreamReader2读取器= (XMLStreamReader2) factory.createXMLStreamReader(in)；final StackUglyAdapter stackAdapter = new StackUglyAdapter(StreamReaderImpl) reader).getInputElementStack())；while (reader.hasNext()) { reader.next()；if (reader.isStartElement()) {reader.isStartElement}}

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。