java 获取月末日期、当天日期、月初日期

String nowTime = new SimpleDateFormat(“yyyy-MM-dd”).format(Calendar.getInstance().getTime());
SimpleDateFormat format=new SimpleDateFormat(“yyyy-MM-dd”); //获取当天日期
Calendar c = Calendar.getInstance();
c.add(Calendar.MONTH, 0);
c.set(Calendar.DAY_OF_MONTH,1);
String firstday= format.format(c.getTime());//1:本月第一天
Calendar ca = Calendar.getInstance();
ca.set(Calendar.DAY_OF_MONTH, ca.getActualMaximum(Calendar.DAY_OF_MONTH));
String lastday= format.format(ca.getTime());//2:本月最后一天