harmony 鸿蒙XML Conversion

2023-10-30
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XML Conversion

Converting XML text into JavaScript objects makes it easier to process and manipulate data. In addition, JavaScript objects are more suitable than XML text for JavaScript applications.

The common library provides the ConvertXML class to convert XML text into JavaScript objects. The input is XML strings and conversion options, and the output is a JavaScript object. For details about the conversion options, see the API reference @ohos.convertxml (XML-to-JavaScript Conversion).

Precautions

To ensure successful XML parsing and conversion, the input XML data must comply with the standard format.

How to Develop

The following steps walk you through on how to convert an XML file into a JavaScript object to obtain the tag values.

Import the convertxml module.

   import convertxml from '@ohos.convertxml';

Pass in an XML file to be converted and set conversion options.

   let xml: string =
    '<?xml version="1.0" encoding="utf-8"?>' +
    '<note importance="high" logged="true">' +
    '    <title>Happy</title>' +
    '    <todo>Work</todo>' +
    '    <todo>Play</todo>' +
    '</note>';
   let options: convertxml.ConvertOptions = {
     // trim: false, indicating that spaces before and after the text are not deleted after conversion.
     // declarationKey: "_declaration", indicating that _declaration is used to identify the file declaration after conversion.
     // instructionKey: "_instruction", indicating that _instruction is used to identify instructions after conversion.
     // attributesKey: "_attributes", indicating that _attributes is used to identify attributes after conversion.
     // textKey: "_text", indicating that _text is used to identify tag values after conversion.
     // cdataKey: "_cdata", indicating that _cdata is used to identify unparsed data after conversion.
     // docTypeKey: "_doctype", indicating that _doctype is used to identify documents after conversion.
     // commentKey: "_comment", indicating that _comment is used to identify comments after conversion.
     // parentKey: "_parent", indicating that _parent is used to identify parent classes after conversion.
     // typeKey: "_type", indicating that _type is used to identify types after conversion.
     // nameKey: "_name", indicating that _name is used to identify tag names after conversion.
     // elementsKey: "_elements", indicating that _elements is used to identify elements after conversion.
     trim: false,
     declarationKey: "_declaration",
     instructionKey: "_instruction",
     attributesKey: "_attributes",
     textKey: "_text",
     cdataKey: "_cdata",
     doctypeKey: "_doctype",
     commentKey: "_comment",
     parentKey: "_parent",
     typeKey: "_type",
     nameKey: "_name",
     elementsKey: "_elements"
   }

Call the conversion function and print the result.

   let conv: convertxml.ConvertXML = new convertxml.ConvertXML();
   let result: object = conv.convertToJSObject(xml, options);
   let strRes: string = JSON.stringify(result); // Convert the JavaScript object into a JSON string for explicit output.
   console.info(strRes);

The output is as follows:

   strRes:
   {"_declaration":{"_attributes":{"version":"1.0","encoding":"utf-8"}},"_elements":[{"_type":"element","_name":"note",
    "_attributes":{"importance":"high","logged":"true"},"_elements":[{"_type":"element","_name":"title",
    "_elements":[{"_type":"text","_text":"Happy"}]},{"_type":"element","_name":"todo",
    "_elements":[{"_type":"text","_text":"Work"}]},{"_type":"element","_name":"todo",
    "_elements":[{"_type":"text","_text":"Play"}]}]}]}