如何在Clojure中强制转换Java类?

有一个 cast 函数在 clojure.core

user> (doc cast)
-------------------------
clojure.core/cast
([c x])
  Throws a ClassCastException if x is not a c, else returns x.

顺便说一下,你不应该用 let* 直接——这只是后面的一个实现细节 let (这是应该在用户代码中使用的内容)。

请注意 cast

user=> (set! *warn-on-reflection* true)
true
user=> (.toCharArray "foo")  ; no reflection needed
#<char[] [C@a21d23b>
user=> (defn bar [x]         ; reflection used
         (.toCharArray x))
Reflection warning, NO_SOURCE_PATH:17 - reference to field toCharArray can't be resolved.
#'user/bar
user=> (bar "foo")           ; but it still works, no casts needed!
#<char[] [C@34e93999>
user=> (defn bar [^String x] ; avoid the reflection with type-hint
         (.toCharArray x)) 
#'user/bar
user=> (bar "foo")
#<char[] [C@3b35b1f3>