Java-通过年和月获取当前月有几个周一并获取周一的日期

Java-通过年和月获取当前月有几个周一并获取周一的日期

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.LinkedList;
import java.util.List;

import com.alibaba.fastjson.JSONObject;


public class DateUtilWeek {
	
	public static void main(String[] args) throws ParseException {
		getWeekS(2022, 1);
	}
	

	public static JSONObject getWeekS(Integer year, Integer month) throws ParseException {
		List<String> weeks = new LinkedList<>();
		int tongji = 0;
		Calendar c = Calendar.getInstance();
		c.set(year, month - 1, 1);
		int mountDay = c.getActualMaximum(Calendar.DAY_OF_MONTH);
		SimpleDateFormat sim = new SimpleDateFormat("yyyy-MM-dd E");
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		for (int i=1;i<=mountDay;i++) {
			String date1 = year + "-";
			if (month < 10) {
				date1 += "0" + month + "-";
			} else {
				date1 += month + "-";
			}
			if (i < 10) {
				date1 += "0" + i;
			} else {
				date1 += i;
			}
			String dateStr = sim.format(sdf.parse(date1));
			String weekStr = dateStr.substring(11,14);
			if ("星期一".equals(weekStr)) {
				weeks.add(date1);
				tongji++;
			}
		}
		JSONObject data = new JSONObject();
		data.put("num", tongji);
		data.put("list", weeks);
		return data;
	}
	}