Convert xml to xsd using java

Question

I am looking for a tool or java code or class library/API that can generate XSD from XML files. (Something like the xsd.exe utility in the .NET Framework sdk)

Answer 1

Check Castor, I think it has the functionality you are looking for. They also provide you with an ant task that creates XSD schemas from XML files.

PS I suggest you to add more specific tags in the future: For instance, using xml, xsd and java will increment the possibility of getting answers.

Answer 2

These tools can provide a good starting point, but they aren't a substitute for thinking through what the actual schema constraints ought to be. You get the opportunity for two kinds of errors: (1) allowing XML that shouldn't be allowed and (2) disallowing XML that should be ok.

As an example, pretend that you want to infer an XSD from a few thousand patient records that include a 'gender' tag (I used to work on medical records software). The tool would likely encounter 'M' and 'F' as values and might deduce that the element is an enumeration. However, other valid (although rarely used) values are B (both), U (unknown), or N (none). These are rare, of course. So, if you used your derived schema as an input validator, it would perform well until a patient with multiple sex organs was admitted to the hospital.

Conversely, to avoid this error, an XSD generator might not add enumerated type restrictions (I can't remember what these are called in schemas), and your application would work well until it encountered an errant record with gender=X.

So, beware. It's best to use these tools only as a starting point. Also, they tend to produce verbose and redundant schemas because they can't figure out patterns as well as humans.