hssfdateutil.java

来自「EXCEL read and write」· Java 代码 · 共 463 行 · 第 1/2 页

            return true;
        }

        return false;
    }

    /**
     * Given a format ID this will check whether the format represents
     *  an internal excel date format or not.
     * @see #isADateFormat(int, java.lang.String)
     */
    public static boolean isInternalDateFormat(int format) {
            switch(format) {
                // Internal Date Formats as described on page 427 in
                // Microsoft Excel Dev's Kit...
                case 0x0e:
                case 0x0f:
                case 0x10:
                case 0x11:
                case 0x12:
                case 0x13:
                case 0x14:
                case 0x15:
                case 0x16:
                case 0x2d:
                case 0x2e:
                case 0x2f:
                    return true;
            }
       return false;
    }

    /**
     *  Check if a cell contains a date
     *  Since dates are stored internally in Excel as double values
     *  we infer it is a date if it is formatted as such.
     *  @see #isADateFormat(int, String)
     *  @see #isInternalDateFormat(int)
     */
    public static boolean isCellDateFormatted(HSSFCell cell) {
        if (cell == null) return false;
        boolean bDate = false;

        double d = cell.getNumericCellValue();
        if ( HSSFDateUtil.isValidExcelDate(d) ) {
            HSSFCellStyle style = cell.getCellStyle();
            int i = style.getDataFormat();
            String f = style.getDataFormatString(cell.getBoundWorkbook());
            bDate = isADateFormat(i, f);
        }
        return bDate;
    }
    /**
     *  Check if a cell contains a date, checking only for internal
     *   excel date formats.
     *  As Excel stores a great many of its dates in "non-internal"
     *   date formats, you will not normally want to use this method.
     *  @see #isADateFormat(int,String)
     *  @see #isInternalDateFormat(int)
     */
    public static boolean isCellInternalDateFormatted(HSSFCell cell) {
        if (cell == null) return false;
        boolean bDate = false;

        double d = cell.getNumericCellValue();
        if ( HSSFDateUtil.isValidExcelDate(d) ) {
            HSSFCellStyle style = cell.getCellStyle();
            int i = style.getDataFormat();
            bDate = isInternalDateFormat(i);
        }
        return bDate;
    }


    /**
     * Given a double, checks if it is a valid Excel date.
     *
     * @return true if valid
     * @param  value the double value
     */

    public static boolean isValidExcelDate(double value)
    {
        return (value > -Double.MIN_VALUE);
    }

    /**
     * Given a Calendar, return the number of days since 1900/12/31.
     *
     * @return days number of days since 1900/12/31
     * @param  cal the Calendar
     * @exception IllegalArgumentException if date is invalid
     */

    static int absoluteDay(Calendar cal, boolean use1904windowing)
    {
        return cal.get(Calendar.DAY_OF_YEAR)
               + daysInPriorYears(cal.get(Calendar.YEAR), use1904windowing);
    }

    /**
     * Return the number of days in prior years since 1900
     *
     * @return    days  number of days in years prior to yr.
     * @param     yr    a year (1900 < yr < 4000)
     * @param use1904windowing
     * @exception IllegalArgumentException if year is outside of range.
     */

    private static int daysInPriorYears(int yr, boolean use1904windowing)
    {
        if ((!use1904windowing && yr < 1900) || (use1904windowing && yr < 1900)) {
            throw new IllegalArgumentException("'year' must be 1900 or greater");
        }

        int yr1  = yr - 1;
        int leapDays =   yr1 / 4   // plus julian leap days in prior years
                       - yr1 / 100 // minus prior century years
                       + yr1 / 400 // plus years divisible by 400
                       - 460;      // leap days in previous 1900 years

        return 365 * (yr - (use1904windowing ? 1904 : 1900)) + leapDays;
    }

    // set HH:MM:SS fields of cal to 00:00:00:000
    private static Calendar dayStart(final Calendar cal)
    {
        cal.get(Calendar
            .HOUR_OF_DAY);   // force recalculation of internal fields
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND, 0);
        cal.get(Calendar
            .HOUR_OF_DAY);   // force recalculation of internal fields
        return cal;
    }


    private static final class FormatException extends Exception {
        public FormatException(String msg) {
            super(msg);
        }
    }

    /**
     * Converts a string of format "HH:MM" or "HH:MM:SS" to its (Excel) numeric equivalent
     *
     * @return a double between 0 and 1 representing the fraction of the day
     */
    public static double convertTime(String timeStr) {
        try {
            return convertTimeInternal(timeStr);
        } catch (FormatException e) {
            String msg = "Bad time format '" + timeStr
                + "' expected 'HH:MM' or 'HH:MM:SS' - " + e.getMessage();
            throw new IllegalArgumentException(msg);
        }
    }
    private static double convertTimeInternal(String timeStr) throws FormatException {
        int len = timeStr.length();
        if (len < 4 || len > 8) {
            throw new FormatException("Bad length");
        }
        String[] parts = TIME_SEPARATOR_PATTERN.split(timeStr);

        String secStr;
        switch (parts.length) {
            case 2: secStr = "00"; break;
            case 3: secStr = parts[2]; break;
            default:
                throw new FormatException("Expected 2 or 3 fields but got (" + parts.length + ")");
        }
        String hourStr = parts[0];
        String minStr = parts[1];
        int hours = parseInt(hourStr, "hour", HOURS_PER_DAY);
        int minutes = parseInt(minStr, "minute", MINUTES_PER_HOUR);
        int seconds = parseInt(secStr, "second", SECONDS_PER_MINUTE);

        double totalSeconds = seconds + (minutes + (hours) * 60) * 60;
        return totalSeconds / (SECONDS_PER_DAY);
    }
    /**
     * Converts a string of format "YYYY/MM/DD" to its (Excel) numeric equivalent
     *
     * @return a double representing the (integer) number of days since the start of the Excel epoch
     */
    public static Date parseYYYYMMDDDate(String dateStr) {
        try {
            return parseYYYYMMDDDateInternal(dateStr);
        } catch (FormatException e) {
            String msg = "Bad time format " + dateStr
                + " expected 'YYYY/MM/DD' - " + e.getMessage();
            throw new IllegalArgumentException(msg);
        }
    }
    private static Date parseYYYYMMDDDateInternal(String timeStr) throws FormatException {
        if(timeStr.length() != 10) {
            throw new FormatException("Bad length");
        }

        String yearStr = timeStr.substring(0, 4);
        String monthStr = timeStr.substring(5, 7);
        String dayStr = timeStr.substring(8, 10);
        int year = parseInt(yearStr, "year", Short.MIN_VALUE, Short.MAX_VALUE);
        int month = parseInt(monthStr, "month", 1, 12);
        int day = parseInt(dayStr, "day", 1, 31);

        Calendar cal = new GregorianCalendar(year, month-1, day, 0, 0, 0);
        cal.set(Calendar.MILLISECOND, 0);
        return cal.getTime();
    }
    private static int parseInt(String strVal, String fieldName, int rangeMax) throws FormatException {
        return parseInt(strVal, fieldName, 0, rangeMax-1);
    }

    private static int parseInt(String strVal, String fieldName, int lowerLimit, int upperLimit) throws FormatException {
        int result;
        try {
            result = Integer.parseInt(strVal);
        } catch (NumberFormatException e) {
            throw new FormatException("Bad int format '" + strVal + "' for " + fieldName + " field");
        }
        if (result < lowerLimit || result > upperLimit) {
            throw new FormatException(fieldName + " value (" + result
                    + ") is outside the allowable range(0.." + upperLimit + ")");
        }
        return result;
    }
}