자바 주말 공휴일 제외 평일 날짜 수(근무일) 구하는 방법

package test;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

public class WorkingDays {

public static void main(String[] args) {
System.out.println("start");

String startMM="201905";
String endMM="201907";

SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");

try{
String startDate=startMM+"01";
Calendar start=Calendar.getInstance();

int syyyy=Integer.partInt(startMM.substring(0,4));
int smm=Integer.partInt(endMM.substring(4,6));

start.set(Calendar.YEAR, syyyy);
start.set(Calendar.MONTH, smm);

int eyyyy=Integer.partInt(endMM.substring(0,4));

int emm=Integer.partInt(endMM.substring(4,6));

end.set(Calendar.YEAR, eyyyy);
end.set(Calendar.MONTH, emm);

int endDay=start.getActualMaximum(start.DAY_OF_MONTH);
String endDate=endMM+endDay;

start.setTime(sdf.parse(startDate));

Calendar end = Calendar.getInstance();
end.setTime(sdf.parse(endDate));

int workingDays = 0;

List alHoliday=new ArrayList();
alHoliday.add("20190501");
alHoliday.add("20190606");

while( !start.after(end) ){
int day=start.get(Calendar.DAY_OF_WEEK);
if( (day != Calendar.SATURDAY) && (day != Calendar.SUNDAY) && !alHoliday.contains(startDate) ){
workingDays++;
}
start.add(Calendar.DATE, 1);
startDate = sdf.format(start.getTime());
}
System.out.println("workingDays="+workingDays);

}catch(Exception e){
e.printStackTrace();
}

System.out.println("end");
}

}