How do I remove namespaces from xml, using java dom?

Question

I have the following code

DocumentBuilderFactory dbFactory_ = DocumentBuilderFactory.newInstance();
Document doc_;
DocumentBuilder dBuilder = dbFactory_.newDocumentBuilder();
StringReader reader = new StringReader(s);
InputSource inputSource = new InputSource(reader);
doc_ = dBuilder.parse(inputSource);
doc_.getDocumentElement().normalize();

Then I can do

doc_.getDocumentElement();

and get my first element but the problem is instead of being job the element is tns:job .

I know about and have tried to use:

dbFactory_.setNamespaceAware(true);

but that is just not what I'm looking for, I need something to completely get rid of namespaces.

Any help would be appreciated, Thanks,

Josh

Answer 1

Use the Regex function. This will solve this issue:

public static String removeXmlStringNamespaceAndPreamble(String xmlString) {
  return xmlString.replaceAll("(<\\?[^<]*\\?>)?", ""). /* remove preamble */
  replaceAll("xmlns.*?(\"|\').*?(\"|\')", "") /* remove xmlns declaration */
  .replaceAll("(<)(\\w+:)(.*?>)", "$1$3") /* remove opening tag prefix */
  .replaceAll("(</)(\\w+:)(.*?>)", "$1$3"); /* remove closing tags prefix */
}

Answer 2

For Element and Attribute nodes:

Node node = ...;
String name = node.getLocalName();

will give you the local part of the node's name.

See Node.getLocalName()

Answer 3

Rather than

dbFactory_.setNamespaceAware(true);

Use

dbFactory_.setNamespaceAware(false);

Although I agree with Tomalak: in general, namespaces are more helpful than harmful. Why don't you want to use them?

---

Edit: this answer doesn't answer the OP's question, which was how to get rid of namespace prefixes . RD01 provided the correct answer to that.

Answer 4

You can pre-process XML to remove all namespaces, if you absolutely must do so. I'd recommend against it, as removing namespaces from an XML document is in essence comparable to removing namespaces from a programming framework or library - you risk name clashes and lose the ability to differentiate between once-distinct elements. However, it's your funeral. ;-)

This XSLT transformation removes all namespaces from any XML document.

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="node()">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*" />
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*">
    <xsl:element name="{local-name()}">
      <xsl:apply-templates select="node()|@*" />
    </xsl:element>
  </xsl:template>

  <xsl:template match="@*">
    <xsl:attribute name="{local-name()}">
      <xsl:apply-templates select="node()|@*" />
    </xsl:attribute>
  </xsl:template>
</xsl:stylesheet>

Apply it to your XML document. Java examples for doing such a thing should be plenty, even on this site. The resulting document will be exactly of the same structure and layout, just without namespaces.

Answer 5

public static void wipeRootNamespaces(Document xml) {       
    Node root = xml.getDocumentElement();
    NodeList rootchildren = root.getChildNodes();
    Element newroot = xml.createElement(root.getNodeName());

    for (int i=0;i<rootchildren.getLength();i++) {
        newroot.appendChild(rootchildren.item(i).cloneNode(true));
    }

    xml.replaceChild(newroot, root);
}

Answer 6

The size of the input xml also needs to be considered when choosing the solution. For large xmls, in the size of ~100k, possible if your input is from a web service, you also need to consider the garbage collection implications when you manipulate a large string. We used String.replaceAll before, and it caused frequent OOM in production with a 1.5G heap size because of the way replaceAll is implemented.

You can reference http://app-inf.blogspot.com/2013/04/pitfalls-of-handling-large-string.html for our findings.

I am not sure how XSLT deals with large String objects, but we ended up parsing the string manualy to remove prefixes in one parse to avoid creating additional large java objects.

public static String removePrefixes(String input1) {
    String ret = null;
    int strStart = 0;
    boolean finished = false;
    if (input1 != null) {
        //BE CAREFUL : allocate enough size for StringBuffer to avoid expansion
        StringBuffer sb = new StringBuffer(input1.length()); 
        while (!finished) {

            int start = input1.indexOf('<', strStart);
            int end = input1.indexOf('>', strStart);
            if (start != -1 && end != -1) {
                // Appending anything before '<', including '<'
                sb.append(input1, strStart, start + 1);

                String tag = input1.substring(start + 1, end);
                if (tag.charAt(0) == '/') {
                    // Appending '/' if it is "</"
                    sb.append('/');
                    tag = tag.substring(1);
                }

                int colon = tag.indexOf(':');
                int space = tag.indexOf(' ');
                if (colon != -1 && (space == -1 || colon < space)) {
                    tag = tag.substring(colon + 1);
                }
                // Appending tag with prefix removed, and ">"
                sb.append(tag).append('>');
                strStart = end + 1;
            } else {
                finished = true;
            }
        }
        //BE CAREFUL : use new String(sb) instead of sb.toString for large Strings
        ret = new String(sb);
    }
    return ret;
}

Answer 7

Tomalak, one fix of your XSLT (in 3rd template):

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="node()">
    <xsl:copy>
        <xsl:apply-templates select="node() | @*" />
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*">
    <xsl:element name="{local-name()}">
        <xsl:apply-templates select="node() | @*" />
    </xsl:element>
  </xsl:template>

  <xsl:template match="@*">
    <!-- Here! -->
    <xsl:copy>
      <xsl:apply-templates select="node() | @*" />
    </xsl:copy>

  </xsl:template>
</xsl:stylesheet>

Answer 8

Instead of using TransformerFactory and then calling transform on it (which was injecting the empty namespace, I transformed as follows:

    OutputStream outputStream = new FileOutputStream(new File(xMLFilePath));
    OutputFormat outputFormat = new OutputFormat(doc, "UTF-8", true);
    outputFormat.setOmitComments(true);
    outputFormat.setLineWidth(0);

    XMLSerializer serializer = new XMLSerializer(outputStream, outputFormat);
    serializer.serialize(doc);
    outputStream.close();