得到指定月的第一天和最后一天

Calendar calendar = Calendar.getInstance();
int month = calendar.get(Calendar.MONTH);
//当月时间的上个月份
calendar.set(Calendar.MONTH, month-1);
//上个月份最后一天        
calendar.set(Calendar.DAY_OF_MONTH,calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
Date strDateTo = calendar.getTime();
System.out.println(DateUtils.format(strDateTo, DateUtils.DATE));
       
 //上个月份第一天        
calendar.set(Calendar.DAY_OF_MONTH,calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
strDateTo = calendar.getTime();
System.out.println(DateUtils.format(strDateTo, DateUtils.DATE));