Java8 - 将非常大的 XML 输入转换为 JSON(带有额外的属性)

Question

我想将一个巨大的 XML 转换为 JSON。每次识别特定的 XML 标签时，我想将标签的 XML 部分转换为 JSON 并且 我想为其添加一个简单的计数器。

重要的是，输入的 XML 非常大，因此不可能将其放入内存 JSON 树中。

所以... <xml><car>...</car><car>...</car>...

转换为

{"number":2,"car":{"name":"car1"}}
{"number":3,"car":{"name":"car2"}}

Answer 1

感谢 Andreas，我终于找到了处理巨大 XML 文件并将匹配的 xml 元素转换为 JSON 的解决方案。

String testCars = "<root><car><name>car1</name></car><other><something>Unknown</something></other><car><name>car2</name></car></root>";
String startElement = "car";
int volgnummer = 1;
XMLInputFactory factory = XMLInputFactory.newInstance();
try {
    XMLStreamReader streamReader = factory.createXMLStreamReader(new StringReader(testCars));
    streamReader.nextTag();
    TransformerFactory tf = TransformerFactory.newInstance();
    Transformer t = tf.newTransformer();
    t.setOutputProperty("omit-xml-declaration", "yes");
    streamReader.nextTag();
    while ( streamReader.isStartElement() ||
          ( ! streamReader.hasNext() && 
            streamReader.nextTag() == XMLStreamConstants.START_ELEMENT)) {
        StringWriter writer = new StringWriter();
        StreamResult result = new StreamResult(writer);
        t.transform(new StAXSource(streamReader), result);
        JSONObject jsonObject = XML.toJSONObject(writer.toString());
        jsonObject.put("sequence", ++volgnummer);
        System.out.println("XmlChunkToJson: " + jsonObject.toString());
    }
} catch (Exception e) {
    e.printStackTrace();
}

XML 输入:

<?xml version="1.0"?>
<root>
  <car>
    <name>car1</name>
  </car>
  <other>
    <something>Unknown</something>
  </other>
  <car>
    <name>car2</name>
  </car>
</root>

输出 JSON:

XmlChunkToJson: {"sequence":2,"car":{"name":"car1"}}
XmlChunkToJson: {"sequence":3,"other":{"something":"Unknown"}}
XmlChunkToJson: {"sequence":4,"car":{"name":"car2"}}