Java獲取月份第一天和最后一天

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

public class test {
	
	private static String startDay = "2020-02-20";

	public static void main(String[] args) {
	    Calendar calendar = Calendar.getInstance();
	    calendar.set(Integer.parseInt(startDay.substring(0,4)), Integer.parseInt(startDay.substring(5,7)) - 1, 1);
            String firstDayOfMonth = new SimpleDateFormat( "yyyy-MM-dd ").format(calendar.getTime());
            System.out.println("第一天："+firstDayOfMonth);
        
            calendar.set(Integer.parseInt(startDay.substring(0,4)), Integer.parseInt(startDay.substring(5,7)), 1);//這里先設置要獲取月份的下月的第一天
            calendar.add(Calendar.DATE, -1);//這里將日期值減去一天，從而獲取到要求的月份最后一天
            String lastDayOfMonth = new SimpleDateFormat( "yyyy-MM-dd ").format(calendar.getTime());
            System.out.println("最后一天："+lastDayOfMonth);
	}
}

參考博客：https://blog.csdn.net/Xiehou_java/article/details/87937749
感謝大佬！！！

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