根據當前日期得到本月月末、上月月末。。。。。。。

private String[] getActdates(String actdate) {//actdate格式爲：2016-10
        SimpleDateFormat sf1 = new SimpleDateFormat("yyyy-MM");
        SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd");
        Date d = new Date();
        try {
            d = sf1.parse(actdate);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        GregorianCalendar gc=new GregorianCalendar();

        //得到上月的最後一天
        gc.setTime(d);
        gc.add(2,-1);
        gc.set(gc.get(Calendar.YEAR),gc.get(Calendar.MONTH),gc.getActualMaximum(Calendar.DAY_OF_MONTH));
        String lastmonthActdate = sf.format(gc.getTime());

        //得到本月的最後一天
        gc.setTime(d);
        gc.set(gc.get(Calendar.YEAR),gc.get(Calendar.MONTH),gc.getActualMaximum(Calendar.DAY_OF_MONTH));
        String curmonthActdate = sf.format(gc.getTime());

        //得到去年的最後一天
        gc.setTime(d);
        gc.add(1,-1);
        gc.set(gc.get(Calendar.YEAR),11,31);
        String lastyearActdate = sf.format(gc.getTime());

        //得到去年本月的最後一天
        gc.setTime(d);
        gc.add(1,-1);
        gc.set(gc.get(Calendar.YEAR),gc.get(Calendar.MONTH),gc.getActualMaximum(Calendar.DAY_OF_MONTH));
        String lastActdate = sf.format(gc.getTime());

        return new String[]{lastmonthActdate, curmonthActdate, lastyearActdate, lastActdate};
    }