To read an instant as a java.util.Date, bind *data-readers* to a map with this var as the value for the 'inst key. The timezone offset will be used to convert into UTC.
;; Parse a string with RFC3339-like timestamp to get a java.util.Date object
(use 'clojure.instant)
(read-instant-date "2017-08-23T10:22:22")
;; #inst "2017-08-23T10:22:22.000-00:00"
;; If no timezone info is included in the input string, GMT is assumed.
;; See clojure.instant/parse-timestamp for the timestamp pattern supported.