datetime.java

第三方的SQL Server and Sybase的jdbc dirver,速度更快

                i = 100 * (n - 49) + i + l;
                this.year  = (short)i;
                this.month = (short)j;
                this.day   = (short)k;
            }
        }
        if (time == TIME_NOT_USED) {
            this.hour   = 0;
            this.minute = 0;
            this.second = 0;
        } else {
            int hours = time / 1080000;
            time = time - hours * 1080000;
            int minutes = time / 18000;
            time = time - (minutes * 18000);
            int seconds = time / 300;
            time = time - seconds * 300;
            time = (int) Math.round(time * 1000 / 300f);
            this.hour = (short)hours;
            this.minute = (short)minutes;
            this.second = (short)seconds;
            this.millis = (short)time;
        }
        unpacked = true;
    }

    /**
     * Converts a calendar date into days since 1900 (Sybase epoch).
     * <p>
     * Algorithm from Fliegel, H F and van Flandern, T C (1968).
     * Communications of the ACM, Vol 11, No 10 (October, 1968).
     *
     * <pre>
     *           INTEGER FUNCTION JD (YEAR,MONTH,DAY)
     *     C
     *     C---COMPUTES THE JULIAN DATE (JD) GIVEN A GREGORIAN CALENDAR
     *     C   DATE (YEAR,MONTH,DAY).
     *     C
     *           INTEGER YEAR,MONTH,DAY,I,J,K
     *     C
     *           I= YEAR
     *           J= MONTH
     *           K= DAY
     *     C
     *           JD= K-32075+1461*(I+4800+(J-14)/12)/4+367*(J-2-(J-14)/12*12)
     *          2    /12-3*((I+4900+(J-14)/12)/100)/4
     *     C
     *           RETURN
     *           END
     * </pre>
     *
     * @throws java.sql.SQLException if the date is outside the accepted range, 1753-9999
     */
    public void packDate() throws SQLException {
        if (year < 1753 || year > 9999) {
            throw new SQLException(Messages.get("error.datetime.range"), "22003");
        }
        date = day - 32075 + 1461 * (year + 4800 + (month - 14) / 12) / 4
                + 367 * (month - 2 - (month - 14) / 12 * 12) / 12
                - 3 * ((year + 4900 + (month -14) / 12) / 100) / 4 - 2415021;
    }

    /**
     * Converts separate time components into a datetime time value.
     */
    public void packTime() {
        time = hour * 1080000;
        time += minute * 18000;
        time += second * 300;
        time += Math.round(millis * 300f / 1000);
        if (time > 25919999) {
            // Time field has overflowed need to increment days
            // Sybase does not allow invalid time component
            time   = 0;
            hour   = 0;
            minute = 0;
            second = 0;
            millis = 0;
            if (date != DATE_NOT_USED) {
                GregorianCalendar cal = (GregorianCalendar)calendar.get();
                cal.set(Calendar.YEAR, this.year);
                cal.set(Calendar.MONTH, this.month - 1);
                cal.set(Calendar.DAY_OF_MONTH, this.day);
                cal.add(Calendar.DATE, 1);
                year   = (short)cal.get(Calendar.YEAR);
                month  = (short)(cal.get(Calendar.MONTH) + 1);
                day    = (short)cal.get(Calendar.DAY_OF_MONTH);
                date++;
            }
        }
    }

    /**
     * Retrieves the current datetime value as a Timestamp.
     *
     * @return the current datetime value as a <code>java.sql.Timestamp</code>
     */
    public Timestamp toTimestamp() {
        if (tsValue == null) {
            if (!unpacked) {
                unpackDateTime();
            }
            GregorianCalendar cal = (GregorianCalendar)calendar.get();
            cal.set(Calendar.YEAR, this.year);
            cal.set(Calendar.MONTH, this.month - 1);
            cal.set(Calendar.DAY_OF_MONTH, this.day);
            cal.set(Calendar.HOUR_OF_DAY, this.hour);
            cal.set(Calendar.MINUTE, this.minute);
            cal.set(Calendar.SECOND, this.second);
            cal.set(Calendar.MILLISECOND, this.millis);
            tsValue = new Timestamp(cal.getTime().getTime());
        }
        return tsValue;
    }

    /**
     * Retrieves the current datetime value as a Date.
     *
     * @return the current datetime value as a <code>java.sql.Date</code>
     */
    public Date toDate() {
        if (dateValue == null) {
            if (!unpacked) {
                unpackDateTime();
            }
            GregorianCalendar cal = (GregorianCalendar)calendar.get();
            cal.set(Calendar.YEAR, this.year);
            cal.set(Calendar.MONTH, this.month - 1);
            cal.set(Calendar.DAY_OF_MONTH, this.day);
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            cal.set(Calendar.MILLISECOND, 0);
            dateValue = new Date(cal.getTime().getTime());
        }
        return dateValue;
    }

    /**
     * Retrieves the current datetime value as a Time.
     *
     * @return the current datetime value as a <code>java.sql.Time</code>
     */
    public Time toTime() {
        if (timeValue == null) {
            if (!unpacked) {
                unpackDateTime();
            }
            GregorianCalendar cal = (GregorianCalendar)calendar.get();
            cal.set(Calendar.YEAR, 1970);
            cal.set(Calendar.MONTH, 0);
            cal.set(Calendar.DAY_OF_MONTH, 1);
            cal.set(Calendar.HOUR_OF_DAY, this.hour);
            cal.set(Calendar.MINUTE, this.minute);
            cal.set(Calendar.SECOND, this.second);
            cal.set(Calendar.MILLISECOND, this.millis);
            timeValue = new Time(cal.getTime().getTime());
        }
        return timeValue;
    }

    /**
     * Retrieves the current datetime value as a Time, Date or Timestamp.
     *
     * @return the current datetime value as an <code>java.lang.Object</code>
     */
    public Object toObject() {
        if (date == DATE_NOT_USED) {
            return toTime();
        }
        if (time == TIME_NOT_USED) {
            return toDate();
        }
        return toTimestamp();
    }

    /**
     * Retrieves the current datetime value as a String.
     *
     * @return the current datetime value as a <code>String</code>
     */
    public String toString() {
        if (stringValue == null) {
            if (!unpacked) {
                unpackDateTime();
            }
            char buf[] = new char[23];
            int p = 0;
            if (date != DATE_NOT_USED) {
                p = 10;
                buf[--p] = (char)('0' + day % 10);
                day /= 10;
                buf[--p] = (char)('0' + day % 10);
                buf[--p] = '-';
                buf[--p] = (char)('0' + month % 10);
                month /= 10;
                buf[--p] = (char)('0' + month % 10);
                buf[--p] = '-';
                buf[--p] = (char)('0' + year % 10);
                year /= 10;
                buf[--p] = (char)('0' + year % 10);
                year /= 10;
                buf[--p] = (char)('0' + year % 10);
                year /= 10;
                buf[--p] = (char)('0' + year % 10);
                p += 10;
                if (time != -1) {
                    buf[p++] = ' ';
                }
            }
            if (time != TIME_NOT_USED) {
                p += 12;
                buf[--p] = (char)('0' + millis % 10);
                millis /= 10;
                buf[--p] = (char)('0' + millis % 10);
                millis /= 10;
                buf[--p] = (char)('0' + millis % 10);
                buf[--p] = '.';
                buf[--p] = (char)('0' + second % 10);
                second /= 10;
                buf[--p] = (char)('0' + second % 10);
                buf[--p] = ':';
                buf[--p] = (char)('0' + minute % 10);
                minute /= 10;
                buf[--p] = (char)('0' + minute % 10);
                buf[--p] = ':';
                buf[--p] = (char)('0' + hour % 10);
                hour /= 10;
                buf[--p] = (char)('0' + hour % 10);
                p += 12;
                if (buf[p-1] == '0') {
                    p--;
                }
                if (buf[p-1] == '0') {
                    p--;
                }
            }
            stringValue = String.valueOf(buf, 0, p);
        }
        return stringValue;
    }
}