Java gets the first day of the month and the last day to get the first and last day of the previous one months

SimpleDateFormat format = new SimpleDateFormat ("Yyyy-mm-dd");

Get the first day of the previous month
Calendar cal_1=calendar.getinstance ();//Get current date
Cal_1.add (Calendar.month,-1);
Cal_1.set (calendar.day_of_month,1);//set to number 1th, the current date is the first day of the month
FirstDay = Format.format (Cal_1.gettime ());
SYSTEM.OUT.PRINTLN ("-----1------firstday:" +firstday);
Get the last day of the previous month
Calendar cale = Calendar.getinstance ();
Cale.set (calendar.day_of_month,0);//set to number 1th, the current date is the first day of the month
Lastday = Format.format (Cale.gettime ());
SYSTEM.OUT.PRINTLN ("-----2------Lastday:" +lastday);


Get the first day of the current month:
Calendar C = calendar.getinstance ();
C.add (calendar.month, 0);
C.set (calendar.day_of_month,1);//set to number 1th, the current date is the first day of the month
String first = Format.format (C.gettime ());
System.out.println ("===============first:" +first);

Get the last day of the current month
Calendar CA = Calendar.getinstance ();
Ca.set (Calendar.day_of_month, Ca.getactualmaximum (Calendar.day_of_month));
String last = Format.format (Ca.gettime ());
System.out.println ("===============last:" +last);

Get the first and last day of a month in a year

Calendar cal = Calendar.getinstance ();
Do not add the following 2 lines, the first and last day of the one months before the current time
Cal.set (calendar.year,2012);
Cal.set (Calendar.month, 6);
Cal.set (Calendar.day_of_month, 1);
Cal.add (Calendar.day_of_month,-1);
String lastdate = Format.format (Cal.gettime ());

Cal.set (Calendar.day_of_month, 1);
String firstdate = Format.format (Cal.gettime ());

System.out.println (lastdate+ "<--->" +firstdate);

Java gets the first day of the month and the last day to get the first and last day of the previous one months