How to inject Processing Instructions with variable parameters into XML using Thymeleaf template engine

Question

I am using Thymeleaf to create an XML document based on a template.

From a template (just showing a piece of it here)

<A>
  ...something goes here...
</A>

I want to produce the document

<A>
  <?foo bar="baz" ?>
</A>

where the value of the attribute bar varies at runtime (in this example it is baz) and should thus be injected from a variable.

I have been looking here, but haven't been able to find anything about XML Processing Instructions.

Answer 1

I have found a workaround that does the job for me:

<A>
  <span th:utext="${'<?foo bar=&quot;' + barValue + '&quot; ?>'}" th:remove="tag"></span>
</A>

It works by creating a <span> tag that contains the PI as text. It finally removes the tag, leaving the PI in place.

I then compose the XML document like this:

Context context = new Context();
context.setVariable("barValue", "baz");
String xml = templateEngine.process("document1", context);