Calendar calendar=Calendar.getInstance(); //获得实例Calendar对象
calendar.set(Calendar.YEAR, 某一年));
calendar.set(Calendar.MONTH,某一月(1月份是0));
int end=calendar.getActualMaximum(calendar.DAY_OF_MONTH); //获得当前月的最后一天
int begin=calendar.getActualMinimum(calendar.DAY_OF_MONTH);//获得当前月的开始一天
calendar.set(Calendar.YEAR, 某一年));
calendar.set(Calendar.MONTH,某一月(1月份是0));
int end=calendar.getActualMaximum(calendar.DAY_OF_MONTH); //获得当前月的最后一天
int begin=calendar.getActualMinimum(calendar.DAY_OF_MONTH);//获得当前月的开始一天