处理时间

        Calendar cTime = Calendar.getInstance();

        startC.set(Calendar.YEAR, 2008);//设置年
         startC.get(Calendar.YEAR)//得到年

        startC.set(Calendar.MONTH, 9- 1);
        startC.get(Calendar.MONTH);

        startC.set(Calendar.DAY_OF_MONTH, 8);
        startC.get(Calendar.DAY_OF_MONTH);

        startC.set(Calendar.HOUR, 7);
        startC.get(Calendar.HOUR);

        startC.set(Calendar.MINUTE, 9);
        startC.get(Calendar.MINUTE);

        startC.set(Calendar.AM_PM, 0);
        startC.get(Calendar.AM_PM);
         
        Calendar  currentTime = Calendar.getInstance();
       if(cTime.before(currentTime)){//判断时间关系，before, after;
         .....
       }
       currentTime .add(Calendar.DAY_OF_MONTH, -1);//取当前日期的前一天.
       currentTime .add(Calendar.HOUR_OF_DAY,15); //15小时以后的日期