从XML到JSON的转换

Question

Is there a standard way to transform an input XML document with structure (scheme) of my choice to an output JSON object with structure (scheme) of my choice?

If it were transformation from input XML to output XML, I would use XSLT.

I can image the following three approaches:

1. Direct transformation from XML to JSON, ie a way to describe transformation XML -> JSON just like XSLT describes transformation XML -> XML.

2. I am aware of JSONML. It is a lossless JSON representation of arbitrary XML document. However, the resulting JSON object does not have the structure of my choice. If there were some standard way to describe transformation JSON -> JSON, I would chain XML -> JSONML and JSONML -> JSON.

3. If there were the opposite to JSONML (let's call it "XMLSON", ie a lossless XML notation of arbitrary JSON object), I would chain XML -> XMLSON (via XSLT) and XMLSON -> JSON.

All the three options have some "if there were". I wonder if there really is some technology to achieve the goal.

Thanks.

Answer 1

The output of XSLT does not need to be XML, so if you are comfortable using that, you can go ahead and use it to output JSON.

A quick search showed up this, which might be a good example for you to start from: https://github.com/bramstein/xsltjson

It defines an XSLT function which takes an XML tree as input, and generates a string as output. Looking into the source, the basic approach is to generate an XML tree with nodes for each JSON object, array, and value, and then apply templates to that which output the JSON syntax itself.

For instance, to output a JSON array, it first generates an XML node of <json:array>...</json:array> , and then applies this template:

  <xsl:template match="json:array" mode="json">
    <xsl:variable name="values">
      <xsl:apply-templates mode="json"/>
    </xsl:variable>
    <xsl:text/>[<xsl:text/>
      <xsl:value-of select="string-join($values/value,',')"/>
    <xsl:text/>]<xsl:text/>
  </xsl:template>

Answer 2

XSLT 3支持将任何XML转换为https://www.w3.org/TR/xslt-30/#schema-for-json中定义的JSON的XML表示形式，然后允许您使用https：// www。 w3.org/TR/xslt-30/#func-xml-to-json将特定的XML转换为JSON。