android 判断指定日期是否为今天昨天

public class DataUtils {
    /**
     * 判断给定字符串时间是否为今日(效率不是很高，不过也是一种方法)
     * @param sdate
     * @return boolean
     */
    public static boolean isToday(String sdate){
        boolean b = false;
        Date time = toDate(sdate);
        Date today = new Date();
        if(time != null){
            String nowDate = dateFormater2.get().format(today);
            String timeDate = dateFormater2.get().format(time);
            if(nowDate.equals(timeDate)){
                b = true;
            }
        }
        return b;
    }

    /**
     * 将字符串转位日期类型
     * @param sdate
     * @return
     */
    public static Date toDate(String sdate) {
        try {
            return dateFormater.get().parse(sdate);
        } catch (ParseException e) {
            return null;
        }
    }

    private final static ThreadLocal dateFormater = new ThreadLocal() {
        @Override
        protected SimpleDateFormat initialValue() {
            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        }
    };

    private final static ThreadLocal dateFormater2 = new ThreadLocal() {
        @Override
        protected SimpleDateFormat initialValue() {
            return new SimpleDateFormat("yyyy-MM-dd");
        }
    };
    private static ThreadLocal DateLocal = new ThreadLocal();
    /**
     * 判断是否为今天(效率比较高)
     * @param day 传入的 时间  "2016-06-28 10:10:30" "2016-06-28" 都可以
     * @return true今天 false不是
     * @throws ParseException
     */
    public static boolean IsToday(String day) throws ParseException {

        Calendar pre = Calendar.getInstance();
        Date predate = new Date(System.currentTimeMillis());
        pre.setTime(predate);

        Calendar cal = Calendar.getInstance();
        Date date = getDateFormat().parse(day);
        cal.setTime(date);

        if (cal.get(Calendar.YEAR) == (pre.get(Calendar.YEAR))) {
            int diffDay = cal.get(Calendar.DAY_OF_YEAR)
                    - pre.get(Calendar.DAY_OF_YEAR);

            if (diffDay == 0) {
                return true;
            }
        }
        return false;
    }

    /**
     * 判断是否为昨天(效率比较高)
     * @param day 传入的 时间  "2016-06-28 10:10:30" "2016-06-28" 都可以
     * @return true今天 false不是
     * @throws ParseException
     */
    public static boolean IsYesterday(String day) throws ParseException {

        Calendar pre = Calendar.getInstance();
        Date predate = new Date(System.currentTimeMillis());
        pre.setTime(predate);

        Calendar cal = Calendar.getInstance();
        Date date = getDateFormat().parse(day);
        cal.setTime(date);

        if (cal.get(Calendar.YEAR) == (pre.get(Calendar.YEAR))) {
            int diffDay = cal.get(Calendar.DAY_OF_YEAR)
                    - pre.get(Calendar.DAY_OF_YEAR);

            if (diffDay == -1) {
                return true;
            }
        }
        return false;
    }

    public static SimpleDateFormat getDateFormat() {
        if (null == DateLocal.get()) {
            DateLocal.set(new SimpleDateFormat("yyyy-MM-dd", Locale.CHINA));
        }
        return DateLocal.get();
    }


}