java日期前一个月

A. java 怎么获取一个月的日期

	/**
	*
	*获取指定月份的日历信息
	*
	*@paramyear
	*年
	*@parammonth
	*月
	*@return
	*/
	publicstaticint[]getMonthCalendar(intyear,intmonth){

		Calendarcl=Calendar.getInstance();
		cl.set(year,month,1);
		intfirstDay=cl.getMinimum(Calendar.DAY_OF_MONTH);
		intlastDay=cl.getMaximum(Calendar.DAY_OF_MONTH);

		int[]day=newint[lastDay];

		for(inti=0;i<lastDay;i++){
			day[i]=i+firstDay;
		}

		returnday;
	}

B. java怎么得到某个月的第一天和最后一天的日期，以2012-06为例

public class DateUtil { /** * 获取给定时间所在周的第一天(Sunday)的日期和最后一天(Saturday)的日期 * * @param calendar * @return Date数组，[0]为第一天的日期，[1]最后一天的日期 */ public Date[] getWeekStartAndEndDate(Calendar calendar) { Date[] dates = new Date[2]; Date firstDateOfWeek, lastDateOfWeek; // 得到当天是这周的第几天 int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK); // 减去dayOfWeek,得到第一天的日期，因为Calendar用0－6代表一周七天，所以要减一 calendar.add(Calendar.DAY_OF_WEEK, -(dayOfWeek - 1)); firstDateOfWeek = calendar.getTime(); // 每周7天，加6，得到最后一天的日子 calendar.add(Calendar.DAY_OF_WEEK, 6); lastDateOfWeek = calendar.getTime(); dates[0] = firstDateOfWeek; dates[1] = lastDateOfWeek; return dates; } /** * 获取给定时间所在月的第一天F的日期和最后一天的日期 * * @param calendar * @return Date数组，[0]为第一天的日期，[1]最后一天的日期 */ public Date[] getMonthStartAndEndDate(Calendar calendar) { Date[] dates = new Date[2]; Date firstDateOfMonth, lastDateOfMonth; // 得到当天是这月的第几天 int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH); // 减去dayOfMonth,得到第一天的日期，因为Calendar用0代表每月的第一天，所以要减一 calendar.add(Calendar.DAY_OF_MONTH, -(dayOfMonth - 1)); firstDateOfMonth = calendar.getTime(); // calendar.getActualMaximum(Calendar.DAY_OF_MONTH)得到这个月有几天 calendar.add(Calendar.DAY_OF_MONTH, calendar .getActualMaximum(Calendar.DAY_OF_MONTH) - 1); lastDateOfMonth = calendar.getTime(); dates[0] = firstDateOfMonth; dates[1] = lastDateOfMonth; return dates; } public static void main(String[] args) { DateUtil dateUtil = new DateUtil(); Calendar now = Calendar.getInstance(); Date[] weekDates = dateUtil.getWeekStartAndEndDate(now); Date[] monthDates = dateUtil.getMonthStartAndEndDate(now); System.out.println("firstDateOfWeek: " + weekDates[0] + " ,lastDateOfWeek: " + weekDates[1]); System.out.println("firstDateOfMonth: " + monthDates[0] + " ,lastDateOfMonth: " + monthDates[1]); }}