如何使用stax / stax2获取XML元素路径？

Question

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

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

在此示例中，路径为/root/a/b。

Answer 1

保持筹码。在START_ELEMENT上按元素名称并将其弹出END_ELEMENT。

这是一个简短的例子。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

＆＃34;编年史职责＆＃34;

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xdmp:node-insert-child() InputElementStack

• 实现适配器以访问InputElementStack，其受保护的mCurrElement和interate父母（这会减慢算法）。

  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);
      }
  }
  

• 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());
          }
      }
  }
  

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。