[JSP] 파라미터로 받은 YYYYMMDD 형태의 날짜가 유효한지 검사

<%@ page contentType="text/html;charset=euc-kr"%>
<%@ page import="java.util.*"%>
<%
        
        String InterfaceID = request.getParameter("IF_DATE");

        // 캘린더 인스턴스 생성
        Calendar day = Calendar.getInstance();

        boolean right = false ;

        if ( InterfaceID.length() == 8 )
        {
                        int nowYear         = Integer.parseInt(InterfaceID.substring(0,4));
                        int nowMonth        = Integer.parseInt(InterfaceID.substring(4,6)) - 1 ;
                        int nowDate         = Integer.parseInt(InterfaceID.substring(6,8));
                        day.set(nowYear, nowMonth, nowDate);
                        
                        if ( InterfaceID.equals(getDateString(day)) ) {
                                right = true;
                        }
        }

        out.print("결과 : " + right);



%>
<%!
        /**
         *  Calendar 객체를 받아서 해당 날자를 YYYYMMDD 형식으로 리턴
         */
        public String getDateString(Calendar day) {
                String str         = "" + day.get(Calendar.YEAR); // 년;
                
                int thisMonth         = day.get(Calendar.MONTH) + 1; // 월 ( 0 ~ 11 )= 0;
                
                if ( thisMonth < 10 ) {
                        str += "0";
                }
                
                str += "" + thisMonth ;
                
                int thisDate         = day.get(Calendar.DATE) ; // 월 ( 0 ~ 11 )= 0;
                
                if ( thisDate < 10 ) {
                        str += "0";
                }
                
                str += "" + thisDate ;
                
                return str;
        }
%>