// 日期转毫秒 

SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddhhmmss");

long millionSeconds = sdf.parse("20120809030000").getTime();//毫秒

System.out.println(millionSeconds);

// 毫秒转日期

Calendar c = Calendar.getInstance();

c.setTimeInMillis(millionSeconds); 

Date date = c.getTime();

System.out.println(sdf.format(date));

http://www.cnblogs.com/alipayhutu/archive/2012/08/08/2627983.html