clojure char int byte 互转

 (.codePointAt (char \好)) ; 不能这样取. 因为 int char 就可以转化了.
 (.codePointAt "好" 0) ; 不能这样取. 因为 int char 就可以转化了.
 (Integer/toHexString (int \好)) ;597d
 (= \u597d \好)
 (map #(Integer/toHexString %) (intToByteArray (int \好))) ;("0" "0" "59" "7d")

(defn intToByteArray [a]
 (byte-array [
              (byte (bit-and (bit-shift-right a 24) 0xff))
              (byte (bit-and (bit-shift-right a 16) 0xff))
              (byte (bit-and (bit-shift-right a 8) 0xff))
              (byte (bit-and a 0xff))
              ])
 )

 (java.nio.charset.Charset/defaultCharset) ;gbk
 (System/getProperty "file.encoding") ;gbk
 (String. (byte-array [(byte 0x43)
                       (byte 0x6c)
                       (byte 0x6f)
                       (byte 0x6a)
                       12
                       32
                       61
                       ;129
                       0x59 0x7d  ;这是好的unicode编码
                       186 195    ;这是"好"的gbk 编码
                       ;(Integer/toBinaryString 186)
                       ;(Integer/toBinaryString 195)
                       2r10111010 2r11000011
                       ]) "gbk")  ;utf8 会乱码
 (String. (byte-array [(byte 0x43)
                       (byte 0x6c)
                       (byte 0x6f)
                       (byte 0x6a)
                       12
                       32
                       61
                       ;129
                       0x59 0x7d  ;这是好的unicode编码
                       186 195    ;这是"好"的gbk 编码
                       ;(Integer/toBinaryString 186)
                       ;(Integer/toBinaryString 195)
                       2r10111010 2r11000011
                       229 165 189
                       ]) "utf8")
 (map #(bit-and % 0xff) (.getBytes "好")) ;(186 195)
 (map #(bit-and % 0xff) (.getBytes "好" "utf-8")) ;(229 165 189)