Some common notes
@Controller: annotation class is class control layer.
@RequestMapping: mark the requested address
@ResponseBody: The java object into json object.
@Valid: labeling the parity data
@PathVariable: accepts uri parameter value assigned address method
Save property in @SessionAttributes braces to session scope
@RequestParam request parameters
@ExceptionAdvice: labeling a class Exception class
@ExceptionHandler: labeling method is a method for exception handling.
@InitBinder: processing date and time parameters
