> You are right that does work

Thanks for the feedback.

> but I think my example is cleaner if you are building dynamically.

You example doesn't do exactly the same thing: you're using a query parser, so all sorts of other features are enabled, such as boolean queries (+field1:foo +field:bar), wildcard queries (prefix*suffix), boost queries (field1:bar^4), phrase queries (field1:"some words") and all sorts of other features that give some special characters a meaning. Which you might want, or you might not.

Anyway, you now have two solutions, which should be more than enough Closing.