問題描述

我有一個巨大的 XML (~2GB)，我需要添加新元素并修改舊元素.例如，我有:

I have a huge XML (~2GB) and I need to add new Elements and modify the old ones. For example, I have:

<books>
    <book>....</book>
    ...
    <book>....</book>
</books>

又想得到:

<books>
   <book>
      <index></index>
      ....
   </book>
   ...
   <book>
      <index></index>
      ....
   </book>
</books>

我使用了以下代碼:

XMLInputFactory inFactory = XMLInputFactory.newInstance();
XMLEventReader eventReader = inFactory.createXMLEventReader(new FileInputStream(file));
XMLOutputFactory factory = XMLOutputFactory.newInstance();
XMLStreamWriter writer = factory.createXMLStreamWriter(new FileWriter(file, true));
while (eventReader.hasNext()) {
   XMLEvent event = eventReader.nextEvent();
   if (event.getEventType() == XMLEvent.START_ELEMENT) {
      if (event.asStartElement().getName().toString().equalsIgnoreCase("book")) {
          writer.writeStartElement("index");
          writer.writeEndElement();
       }
    }
}
writer.close();

但結果如下:

<books>
   <book>....</book>
   ....
   <book>....</book>
</books><index></index>

有什么想法嗎?

推薦答案

試試這個

    XMLInputFactory inFactory = XMLInputFactory.newInstance();
    XMLEventReader eventReader = inFactory.createXMLEventReader(new FileInputStream("1.xml"));
    XMLOutputFactory factory = XMLOutputFactory.newInstance();
    XMLEventWriter writer = factory.createXMLEventWriter(new FileWriter(file));
    XMLEventFactory eventFactory = XMLEventFactory.newInstance();
    while (eventReader.hasNext()) {
        XMLEvent event = eventReader.nextEvent();
        writer.add(event);
        if (event.getEventType() == XMLEvent.START_ELEMENT) {
            if (event.asStartElement().getName().toString().equalsIgnoreCase("book")) {
                writer.add(eventFactory.createStartElement("", null, "index"));
                writer.add(eventFactory.createEndElement("", null, "index"));
            }
        }
    }
    writer.close();

注意事項

new FileWriter(file, true) 附加到文件末尾，你幾乎不需要它

new FileWriter(file, true) is appending to the end of the file, you hardly really need it

equalsIgnoreCase("book") 是個壞主意，因為 XML 區分大小寫

equalsIgnoreCase("book") is bad idea because XML is case-sensitive

這篇關于如何通過 StAX 修改一個巨大的 XML 文件?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！