code: public static String getCharsetOfContentType(String rawContentType, String defaultEncoding) {
          
          if (rawContentType.contains("charset=")) {
              String charset = rawContentType.split("charset=") [1];
         
              return charset;
          } else {
              return defaultEncoding;
          }
          
      }
docs: A http content type should contain a character set like
  "application/json; charset=utf-8".
  
  If you only want to get the character set you can use this method.
  
  See also: http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1
  
  @param rawContentType "application/json; charset=utf-8" or "application/json"
  @return only the character set like utf-8 OR the defaultEncoding when not set