Parsing XML with java - does not get all xml values

Question

Trying to parse xml to get "CreDtTm" tag value from this XML (pasted not the whole):

    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Document xmlns="urn:iso:std:iso:20022:tech:xsd:pain.001.001.03">
    <CstmrCdtTrfInitn>
        <GrpHdr>
            <MsgId>SANDISS_2020_10_08_001</MsgId>
            <CreDtTm>2020-10-15T18:15:33</CreDtTm>
            <NbOfTxs>3</NbOfTxs>
            <CtrlSum>36.00</CtrlSum>
            <InitgPty>
                <Nm>Bank</Nm>
                <Id>
                    <OrgId>
                        <Othr>
                            <Id>40100</Id>
                            <SchmeNm>
                                <Cd>COID</Cd>
                            </SchmeNm>
                        </Othr>
                    </OrgId>
                </Id>
            </InitgPty>
        </GrpHdr>

However, getting not all values

Here is the method for parsing and editing xml (writing back to XML file is skipped atm)

 public void modifyXmlFile(String filePath, Map<String, String> tagValuesToChange) {
    try {
      DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
      DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
      Document document = docBuilder.parse(filePath);
      XPath xpath = XPathFactory.newInstance().newXPath();

      for (Map.Entry<String, String> entry : tagValuesToChange.entrySet()) {
        Node node = (Node) xpath.compile(entry.getKey()).evaluate(document, XPathConstants.NODE); //**This becomes null**
        node.setTextContent(entry.getValue());
      }

Basically tag is not found and node variable is set to null. Not sure why? Can you help me out?

Answer 1

Running you sample leads me to believe your key in the tagValuesToChange Map is the name of the tag and not a valid XPath expression. Try using //CreDtTm as the key to your map, and see if that works.

I was able to reproduce the NullPointerException when I used the name of the tag as the Map key. Using the XPath expression I suggested, the code was able to find the node and update the text content.