Offline XML Validation with Java

Question

I need to figure out how to validate my XML files with schema's offline. After looking around for a couple of days, what I was able to find was basically that I needed to have an internal reference to the schema. I needed to find them, download them, and change the reference to a local system path. What I was unable to find was exactly how to do that. Where and how can I change the reference to point internally instead of externally? What is the best way to download the schemas?

Answer 1

There are three ways you could do this. What they all have in common is that you need a local copy of the schema document(s). I'm assuming that the instance documents currently use xsi:schemaLocation and/or xsi:noNamespaceSchemaLocation to point to a location holding the schema document(s) on the web.

(a) Modify your instance documents to refer to the local copy of the schema documents. This is usually inconvenient.

(b) Redirect the references so that a request for a remote file is redirected to a local file. The way to set this up depends on which schema validator you are using and how you are invoking it.

(c) Tell the schema processor to ignore the values of xsi:schemaLocation and xsi:noNamespaceSchemaLocation, and to validate instead against a schema that you supply using your schema processor's invocation API. Again the details depend on which schema processor you are using.

My preferred approach is (c): if only because when you are validating a source document, then by definition you don't fully trust it - so why should you trust it to contain a correct xsi:schemaLocation attribute?