Date日期类型操作

private static final String DEFAULTPATTERN = "yyyy-MM-dd";private static final String NORMALPATTERN = "yyyy-MM-dd hh:mm:ss";

<span style="white-space:pre">	</span>private static final String DEFAULTPATTERN = "yyyy-MM-dd";
private static final String NORMALPATTERN = "yyyy-MM-dd hh:mm:ss";
/**
* 把日期字符串转为java.util.Date类型
*/
public static Date strToDate(String dateStr,String parttern) throws Exception{
if (parttern == null || parttern.equals("")){
parttern = DEFAULTPATTERN;
}
SimpleDateFormat sdf=new SimpleDateFormat(parttern);
return sdf.parse(dateStr);
}

/*** 获取上个月第一天* @return*/public static Date getFirstDayOfLastMonth(){Calendar c = Calendar.getInstance();c.add(Calendar.MONTH, -1);c.set(Calendar.DAY_OF_MONTH,1);c.set(Calendar.HOUR_OF_DAY, 0);c.set(Calendar.MINUTE, 0);c.set(Calendar.SECOND, 0);return c.getTime();}

/*** 获取上个月最后一天* @return*/public static Date getLastDayOfLastMonth(){DateFormat format = new SimpleDateFormat("yyyy-MM-dd");Calendar c = Calendar.getInstance();c.add(Calendar.MONTH, -1);c.set(Calendar.DAY_OF_MONTH, c.getActualMaximum(Calendar.DAY_OF_MONTH));String dateStr = format.format(c.getTime());try{return strToDate(dateStr+" 23:59:59","yyyy-MM-dd hh:mm:ss");}catch(Exception e){return null;}

   /*** 获取日期的年份* @param date* @return*/public static int getYear(Date date){Calendar c = Calendar.getInstance();c.setTime(date);return c.get(Calendar.YEAR);}

   /*** 获取日期的月份* @param date* @return*/public static int getMonth(Date date){Calendar c = Calendar.getInstance();c.setTime(date);return c.get(Calendar.MONTH)+1;}

   /*** 获取上一年的年份*/public static int getLastYear(){Calendar c = Calendar.getInstance();c.add(Calendar.YEAR, -1);return c.get(Calendar.YEAR);}

   /*** 获取某年某月的最后一天*/public static String getLastDayOfMonth(int year, int month){DateFormat format = new SimpleDateFormat("yyyy-MM-dd");Calendar c = Calendar.getInstance();c.set(Calendar.YEAR, year);c.set(Calendar.MONTH, month-1);c.set(Calendar.DAY_OF_MONTH, c.getActualMaximum(Calendar.DATE));String dateStr = format.format(c.getTime());return dateStr;}