如何使用 stax/stax2 获取 XML 元素路径？

Question

我想在使用 java StAX2 解析器解析 XML 时获取元素路径。如何获取当前元素路径信息？

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

在此示例中，路径为 /root/a/b。

Answer 1

保留堆栈。在 START_ELEMENT 上推送元素名称并在 END_ELEMENT 上弹出它。

这是一个简短的例子。除了打印正在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;
            }
        }
    }
}

Answer 2

"The chronicler's duty"

方法一：专用栈，@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();
        }
    }
}

方法二（丑）：黑客攻击Woodstox's`InputElementStack`

实施适配器以访问 InputElementStack、其受保护的 mCurrElement 并与父级交互（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);
    }
}

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());
        }
    }
}

带有专用堆栈的方法 1 更好，因为 API 独立于实现并且与 方法 2[=35 一样快=].

如何使用 stax/stax2 获取 XML 元素路径？

How to get XML element path using stax/stax2?

java

xml

stax

方法一：专用栈，@teppic建议

方法二（丑）：黑客攻击Woodstox'sInputElementStack

方法二（丑）：黑客攻击Woodstox's`InputElementStack`