/**
 * fk--folder key,dk--doc key -->value is key string
 * dt--doc type,ft--folder type -->both have 19 key options: 
 * bom tr amend history help info loeid cust cust0-cust9 custhist
 * folder type only seen as "history" in toc,why ??do we use other ones? -- it only has one child
 * doc type only seen two "tr" and "history" in toc??-- it only has one child 
 * node with "folder type="history"" is the only child of it parent either "<doc type="tr" key="xxx" trnum="xxx"....." or "<doc type="tr"  trnum="xxx""
 * <folder type="history"  could has more then one doc children .e.g. title="History of AMM31-32-00-720-807" in 700/amm
 * 
 * 
 * 
 * folder element has the follwing to identify itself:
 * 	1, key 
 * 	2, type="history",  in this case, folder is the only child of doc element with type ="tr"?????
 * 
 * doc element has the following to identify itself
 * 	1, key
 * 	2, type="tr" trnum="xxxxx"
 * 	3, type="history", in this case, doc isthe only child of a folder element???
 * 
 * 
 * 
 * the return json format likes following: 
 * [
 * { "data" : "A node", "children" , "state" : "open" },
 * { "data" : "Only child", "state" : "closed" },
 *	"Ajax node"
 *	]
 */

public class XMLToJson
{
	private static final Map<String, String> pathMap;
	static
	{
		Map<String, String> aMap = new HashMap<String, String>();
		aMap.put("fk", "folder[@key");
		aMap.put("ft", "folder[@type");
		aMap.put("fth", "folder[@type='history'");
		aMap.put("dk", "doc[@key");
		aMap.put("dt", "doc[@type");
		aMap.put("dth", "doc[@type='history'");
		aMap.put("dtrn", "doc[@trnum");
		pathMap = Collections.unmodifiableMap(aMap);
	}

	Util util = new Util();

	/*
	 * @param url the path to TOC.xml
	 * @param xPathString the short format searched node path
	 * @throws DocumentException
	 * 
	 * sample xPathString : "fk:AMM24_fk:AMM24-FM_dk" 
	 */
	@SuppressWarnings({ "unchecked" })
	public String getJson(URL url, String xPathString) throws Exception
	{
		Document TOCDoc = util.getDocument(url);
		String jsonString = "[";

		Element node = null;
		if (xPathString.equals("/"))
		{

			node = TOCDoc.getRootElement();
		}
		else
		{
			String realXPathString = pathMapping(xPathString);
			System.out.println(realXPathString);
			node = (Element) TOCDoc.selectSingleNode(realXPathString);
		}
		//List<Element>  li = node.elements();
		for (Iterator<Element> i = node.elementIterator(); i.hasNext();)
		{
			Element elem = (Element) i.next();
			String eleName = elem.getName();
			Boolean hasChildren = false;
			if ((elem.elements().size() > 0))
			{
				hasChildren = true;
				//current element has children itself, state shoud be "closed"

			}
			List<Attribute> list = elem.attributes();
			String titleAttrContent = elem.attributeValue("title");
			//Boolean isFileAttr = false;
			String fileAttrContent = elem.attributeValue("file");
			//if  (fileAttrContent.isEmpty() )
			if (eleName == "doc")
			{
				//doc element always has "file" attribute

				for (Attribute attribute : list)
				{
					jsonString = jsonString.concat("{");
					String attrName = attribute.getName();
					//System.out.println("doc arribute Name : " + attrName);
					//each one has to have "data" line, "attr" line "state" line and "children" line
					jsonString = jsonString.concat("'data':'").concat(titleAttrContent).concat("',");
					if (attrName.equals("key"))
					{
						String keyContent = elem.attributeValue("key");
						jsonString = jsonString.concat("'attr':{'id':'").concat(xPathString).concat("_dk:").concat(keyContent).concat("','file':'").concat(fileAttrContent).concat("'}");

						break;
					}
					else if (attrName.equals("trnum"))
					{

						String trnumContent = elem.attributeValue("trnum");
						jsonString = jsonString.concat("'attr':{'id':'").concat(xPathString).concat("_dtrn:").concat(trnumContent).concat("','file':'").concat(fileAttrContent).concat("'}");

						break;
					}
					/*		else if (attrName.equals("type"))//type attribute for doc element won't determite what exactly the element is 
							{
								String typeContent = elem.attributeValue("type");
								//doc element has type "history"
								if (typeContent == "history"){
									jsonString = jsonString.concat("'attr':{'id':'").concat(xPathString).concat("_dth,");
								}else if (typeContent == "?????"){
									//any values for type attribute need to concern???? 
								}

							}
							else if (attrName.equals("file"))
							{

							}*/
				}
				if (hasChildren)
				{
					//state set up as "closed" and no need to set up "children" field
					jsonString = jsonString.concat(",'state':'closed'");

				}
				else
				{
					//no need to put anything
					//jsonString = jsonString.concat("'state':'???'");
				}
				jsonString = jsonString.concat("},");
			}

			else if (eleName == "folder")
			{
				jsonString = jsonString.concat("{");
				for (Attribute attribute : list)
				{
					String attrName = attribute.getName();
					jsonString = jsonString.concat("'data':'").concat(titleAttrContent).concat("',");
					if (attrName.equals("key"))
					{
						String keyContent = elem.attributeValue("key");
						jsonString = jsonString.concat("'attr':{'id':'").concat(xPathString).concat("_fk:").concat(keyContent).concat("'}");
						if (fileAttrContent != null)
						{
							jsonString = jsonString.concat("','file':'").concat(fileAttrContent).concat("'}");
						}

						break;
					}
					else if (attrName.equals("type"))
					{
						String typeContent = elem.attributeValue("type");
						//doc element has type "history"
						if (typeContent == "history")
						{
							jsonString = jsonString.concat("'attr':{'id':'").concat(xPathString).concat("_fth,");

						}
						else if (typeContent == "?????")
						{
							//any values need to concern???? 
						}
						break;

					}

				}
				jsonString = jsonString.concat("},");
			}
			continue;
		}
		//return list;
		jsonString = jsonString.substring(0, jsonString.length() - 1);
		jsonString = jsonString.concat("]");
		return jsonString;

	}

	/*
	 * read xpathstring from post request and generate the real xpath for toc
	 */
	public String getXPathString()
	{
		//readPostRequest()
		return null;
	}

	/*
	 * post string looks like : "fk:LOETR_dtrn:TR12-118_fth_dth"
	 * it represents the inner doc elemnet:
	 * <folder key="LOETR" type="loetr" title="List of Effective TRs" file="loetr.html">
	 *		<doc type="tr" trnum="TR12-118" trdate="May 07/2012" title="[TR12-118] TASK AMM12-31-00-660-806 - Inspection and Removal of De-Hydrated Anti-Icing Fluid inside the Flight Control Surfaces" file="TR12-118.pdf" refloc="AMM12-31-00-660-806">
	 * 			<folder type="history" title="History of AMM12-31-00-660-806">
	 *   			<doc title="TASK 12-31-00-660-806 - Inspection and Removal of De-Hydrated Anti-Icing Fluid inside the Flight Control Surfaces" file="AMM12-31-00-660-806.pdf" type="history" refloc="AMM12-31-00-660-806"/>
	 * </folder>
	 * the xpath string should be:
	 * folder[@key="LOETR"]/doc[@trnum="TR12-118"]/folder[@type="history"]/doc[@type="history"]
	 * 
	 * 
	 * the String : "fk:AMM24_fk:AMM24-FM_dk:CTOC-24" 
	 * it represents the inner doc with attribute file="CTOC-24.pdf"
	 * the string : "fk:AMM24_fk:AMM24-00-00_fk:AMM24-00-00-02_dk:AMM24-00-00-700-801" represents
	 * <folder key="AMM24" title="CH 24 - Electrical Power">
	 *		<folder key="AMM24-FM" title="Front Matter">
	 * 			<doc key="CTOC-24" title="Table of Contents" file="CTOC-24.pdf"/>
	 *		</folder>
	 *		<folder key="AMM24-00-00" title="24-00-00 - General">
	 * 			<folder key="AMM24-00-00-02" title="General - Maintenance Practices">
	 *   			<doc key="AMM24-00-00-700-801" title="TASK 24-00-00-700-801 - AC Power, DC Power and Battery Maintenance Practice Recommendations" file="AMM24-00-00-700-801.pdf"/>
	 * 
	 * it can be even optimized as :
	 * "fk:AMM24_fk:00-00_fk:02_dk:AMM24-00-00-700-801"
	 * if the inner key fully include the previous key, omit it, otherwise use full string   
	 * the xpath string should be:
	 * folder[@key="AMM24"]/folder[@key="AMM24-00-00"]/folder[@key="AMM24-00-00-02"]/doc[@key="AMM24-00-00-700-801"]
	 *  
	 * if shortXPath is ?? which means the query based on the root of the document
	 * 
	 * 	 
	 */
	public String pathMapping(String shortXPath) throws Exception
	{
		String tagetString = null;
		if (shortXPath.equals(""))
		{
			tagetString = "//toc";
		}
		else
		{
			tagetString = "//";
		}

		int newStart = 0;
		String segString = "";
		String valueString = "";
		//dth???
		//need mapping all senarios
		//already??
		while (shortXPath.indexOf("_", newStart) > -1)
		{
			int keyValueSepPos = 0;
			String keyString = "";//not necessary key, might be type attribute
			segString = shortXPath.substring(newStart, shortXPath.indexOf("_", newStart));
			newStart = shortXPath.indexOf("_", newStart) + 1;//new start search point
			//System.out.println(newStart);
			if (segString.indexOf(":") > 0)
			{
				keyValueSepPos = segString.indexOf(":");
				keyString = segString.substring(0, keyValueSepPos);
				valueString = segString.substring(keyValueSepPos + 1);
				if (pathMap.get(keyString).length() > 0)
				{
					tagetString = tagetString.concat(pathMap.get(keyString));
				}
				else
				{
					throw new Exception("no mapping found");
				}
				tagetString = tagetString.concat("='").concat(valueString).concat("']/");
			}
		}
		//this is for scenerio either no "_" or sub string after "_"
		segString = shortXPath.substring(newStart);
		System.out.println(segString);
		if (segString.indexOf(":") > 0)
		{
			int lastKeyValueSepPos = segString.indexOf(":");
			String lastKeyString = segString.substring(0, lastKeyValueSepPos);
			String lastValueString = segString.substring(lastKeyValueSepPos + 1);
			if (pathMap.get(lastKeyString).length() > 0)
			{
				tagetString = tagetString.concat(pathMap.get(lastKeyString));
			}
			else
			{
				throw new Exception("no mapping found");
			}
			tagetString = tagetString.concat("='").concat(lastValueString).concat("']");
		}
		return tagetString;

	}

	public static void main(String[] args) throws Exception
	{
		XMLToJson x2j = new XMLToJson();
		String test = "fk:AMM24_fk:AMM24-FM";

		test = "";
		System.out.println(x2j.getJson(new URL("http://localhost:8080/WebNavSpring/q400/amm/toc.xml"), test));
		//System.out.println(x2j.pathMapping(test));

	}
}

easy clean code to convert XML to JSON .

By used in Major Airspace company , 2019-03-15 17:59:54