Common Code -- DateUtils and code -- dateutils

Common Code -- DateUtils and code -- dateutils

I often encounter date processing issues at work. Of course there are some excellent open-source libraries (such as joda-time, which are very powerful). However, I prefer to write some common code, after all, there are not many functions actually used in open-source libraries. If we import them into the database, I personally feel that some resources are wasted (this is my opinion ). The following is a commonly used tool class, DateUtils, which only encapsulates some methods that are commonly used in my work. It is posted here. If the code is inappropriate, please point out (I am very grateful ):

/** * @author ying.dong * DateUtils */public class DateUtils {    private static final ThreadLocal<SimpleDateFormat> threadLocal = new ThreadLocal<SimpleDateFormat>();        /**     * define datePattern     * @author ying.dong     *     */    public enum DatePattern {                DATE_TIME_PATTERN("yyyy-MM-dd HH:mm:ss"), DATE_PATTERN("yyyy-MM-dd"), DATE_NO_SYMBOL_PATTERN("yyyyMMdd");                private String datePattern;                private DatePattern(String pattern) {            this.datePattern = pattern;        }        public String getDatePattern() {            return this.datePattern;        }    }        /**     * define operation unit     * @author ying.dong     *     */    public enum OperationUnit {        YEAR, MONTH, DAY, HOUR, MINUTE, SECOND;    }        /**     * get SimpleDateFormat instance by ThreadLocal     * @return     */    private static SimpleDateFormat getSimpleDateFormat() {        SimpleDateFormat formatter = threadLocal.get();        if (formatter == null) {            formatter = new SimpleDateFormat();            threadLocal.set(formatter);        }        return formatter;    }        /**     * config DateFomatter     * @param datePattern     */    private static SimpleDateFormat configFormatterPattern(DatePattern datePattern) {        SimpleDateFormat formatter = getSimpleDateFormat();        formatter.applyPattern(datePattern.getDatePattern());        return formatter;    }        /**     * parse calendar to String     * @param calendar     * @return     */    public static String parseDate2Str(Calendar calendar) {        return parseDate2Str(DatePattern.DATE_TIME_PATTERN, calendar.getTime());    }        /**     * parse date to String     * @param date     * @return     */    public static String parseDate2Str(Date date) {        return parseDate2Str(DatePattern.DATE_TIME_PATTERN, date);    }        /**     * parse calendar to String     * @param datePattern     * @param calendar     * @return String     */    public static String parseDate2Str(DatePattern datePattern, Calendar calendar) {        return parseDate2Str(datePattern, calendar.getTime());    }        /**     * parse Date to String     * @param datePattern     * @param date     * @return String     */    public static String parseDate2Str(DatePattern datePattern, Date date) {        SimpleDateFormat formatter = configFormatterPattern(datePattern);        return formatter.format(date);    }        /**     * parse String to Date     * @param datePattern     * @param dateStr     * @return Date     * @throws ParseException     */    public static Date parseStr2Date(DatePattern datePattern, String dateStr) throws ParseException {        SimpleDateFormat formatter = configFormatterPattern(datePattern);        return formatter.parse(dateStr);    }        /**     * parse timestamp String to date     * @param timestampStr     * @return     */    public static Date parseTimestampStr2Date(String timestampStr) {        long timestamp = Long.parseLong(timestampStr) * 1000;        return parseTimestampStr2Date(timestamp);    }        /**     * parse timestamp to date     * @param timestamp     * @return     */    public static Date parseTimestampStr2Date(long timestamp) {        Calendar calendar = Calendar.getInstance();        calendar.setTimeInMillis(timestamp * 1000);        return calendar.getTime();    }            /**     * calendar plus operation     * @param unit     * @param amount     * @param calendar     * @return     */    public static Calendar plus(OperationUnit unit, int amount, Calendar calendar) {        switch (unit) {        case YEAR:            calendar.add(Calendar.YEAR, amount);            break;                case MONTH:                calendar.add(Calendar.MONTH, amount);                break;                case DAY:            calendar.add(Calendar.DAY_OF_YEAR, amount);            break;                    case HOUR:            calendar.add(Calendar.HOUR_OF_DAY, amount);            break;                    case MINUTE:            calendar.add(Calendar.MINUTE, amount);            break;                    case SECOND:            calendar.add(Calendar.SECOND, amount);            break;        default:            break;        }        return calendar;    }        /**     * date plus operation     * @param unit     * @param amount     * @param date     * @return     */    public static Date plus(OperationUnit unit, int amount, Date date) {        Calendar calendar = Calendar.getInstance();        calendar.setTime(date);        calendar = plus(unit, amount, calendar);        return calendar.getTime();    }        /**     * date plus operation with timestamp     * @param date     * @param timestamp     * @return     */    public static Date plus(Date date, long timestamp) {        timestamp = date.getTime() + timestamp * 1000;        date.setTime(timestamp);        return date;    }        /**      * calendar minus operation     * @param unit     * @param amount     * @param calendar     * @return     */    public static Calendar minus(OperationUnit unit, int amount, Calendar calendar) {        return plus(unit, -amount, calendar);    }        /**     * date minus operation     * @param unit     * @param amount     * @param date     * @return     */    public static Date minus(OperationUnit unit, int amount, Date date) {        return plus(unit, -amount, date);     }        /**     * date minus operation with timestamp     * @param date     * @param timestamp     * @return     */    public static Date minus(Date date, long timestamp) {        return plus(date, -timestamp);    }        /**     * whether the date is before when     * @param date     * @param when     * @return     * @throws ParseException     */    public static boolean isBefore(Date date, String when) throws ParseException {        Date whenDate = parseStr2Date(DatePattern.DATE_TIME_PATTERN, when);        return isBefore(date, whenDate);    }        /**     * whether the date is before when     * @param date     * @param when     * @param datePattern     * @return     * @throws ParseException     */    public static boolean isBefore(Date date, String when, DatePattern datePattern) throws ParseException {        Date whenDate = parseStr2Date(datePattern, when);        return isBefore(date, whenDate);    }        /**     * whether the date is before when     * @param date     * @param when     * @return     */    public static boolean isBefore(Date date, Date when) {        return date.before(when);    }        /**     * whether the date is after when     * @param date     * @param when     * @return     * @throws ParseException     */    public static boolean isAfter(Date date, String when) throws ParseException {        Date whenDate = parseStr2Date(DatePattern.DATE_TIME_PATTERN, when);        return isAfter(date, whenDate);    }        /**     * whether the date is after when     * @param date     * @param when     * @param datePattern     * @return     * @throws ParseException     */    public static boolean isAfter(Date date, String when, DatePattern datePattern) throws ParseException {        Date whenDate = parseStr2Date(datePattern, when);        return isAfter(date, whenDate);    }        /**     * whether the date is after when     * @param date     * @param when     * @return     */    public static boolean isAfter(Date date, Date when) {        return date.after(when);    }    }

Currently, we know that the parseStr2Date method does not verify the format of the input dataPattern (regular expressions are required here, so it is relatively lazy and not written ).