This article shares the DateUtils tool class for time conversion for your reference. The specific content is as follows
import java.sql.Timestamp;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.HashMap;import java.util.Map;import java.util.Map;import net.sf.json.JSONObject;/** * Time and Date Tool Class* * @author wul * 2015-12-31 */public class DateUtil { public static final String DATE_NORMAL_FORMAT = "yyyy-MM-dd"; public static final String DATETIME_NORMAL_FORMAT = "yyyy-MM-dd HH:mm:ss"; public static final String DATE_COMPACT_FORMAT = "yyyyMMdd"; public static final String DATETIME_COMPACT_FORMAT = "yyyMMddHHmmss"; public static final String YM_NORMAL_FORMAT = "yyyy-MM"; public static final String YM_COMPACT_FORMAT = "yyyyMM"; /** * String to Timestamp * @param dateStr * @return * @author wul * 2016-1-17 */ public static Timestamp stringToTimestamp(String dateStr) { try { if(dateStr.length() <= 10) { dateStr += " 00:00:00"; } return Timestamp.valueOf(dateStr); } catch (Exception e) { e.printStackTrace(); return null; } } /** * String to Date * @param dateStr * @param format * @return * @author wul * 2016-1-17 */ public static Date stringToDate(String dateStr, String format) { if(dateStr == null || "".equals(dateStr)){ return null; } Date date = null; //Note that the format of format should match the format of date String SimpleDateFormat sdf = new SimpleDateFormat(format); try { date = sdf.parse(dateStr); } catch (Exception e) { e.printStackTrace(); } return date; } /** * Date to String * @param date * @param format * @return * @author wul * 2016-1-17 */ public static String dateToString(Date date, String format) { SimpleDateFormat sdf = new SimpleDateFormat(format); String currentDate = sdf.format(date); return currentDate; } /** * Date to Timestamp * @param date * @return * @author wul * 2016-1-17 */ public static Timestamp dateToTimestamp(Date date) { Timestamp ts = new Timestamp(date.getTime()); return ts; } /** * Timestamp to String * @param ts * @return * @author wul * 2016-1-17 */ public static String timestampToString(Timestamp ts) { String tsStr = null; SimpleDateFormat sdf = new SimpleDateFormat(DATETIME_NORMAL_FORMAT); try { tsStr = sdf.format(ts); } catch (Exception e) { e.printStackTrace(); } return tsStr; } /** * Timestamp to Date * @param ts * @return * @author wul * 2016-1-17 */ public static Date timestampToDate(Timestamp ts) { return ts; } /** * Get the current time and format: yyyy-MM-dd HH:mm:ss * @return */ public static String getCurrentTimeNormal() { SimpleDateFormat sdf = new SimpleDateFormat(DATETIME_NORMAL_FORMAT); String currentDate = sdf.format(new Date()); return currentDate; } /** * Get the current time and format: yyyyMMddHHmmss * @return */ public static String getCurrentTimeCompact() { SimpleDateFormat sdf = new SimpleDateFormat(DATETIME_COMPACT_FORMAT); String currentDate = sdf.format(new Date()); return currentDate; } /** * Get the current time and format: yyyy-MM-dd * @return */ public static String getCurrentDateNormal() { SimpleDateFormat sdf = new SimpleDateFormat(DATE_NORMAL_FORMAT); String currentDate = sdf.format(new Date()); return currentDate; } /** * Get the current time and format: yyyyMMdd * @return */ public static String getCurrentDateCompact() { SimpleDateFormat sdf = new SimpleDateFormat(DATE_COMPACT_FORMAT); String currentDate = sdf.format(new Date()); return currentDate; } /** * Format 20101202 time to 2010-12-02 * * @param DateString Time format: yyyyMMdd * @return */ public static String getDateCompactToNormal(String DateString){ StringBuilder sb = new StringBuilder(); sb.append(DateString.substring(0,4)).append("-").append(DateString.subSequence(4, 6)).append("-").append(DateString.substring(6, 8)); return sb.toString(); } /** * Format 20101202101423 time to 2010-12-02 10:14:23 * * @param DateString Time format: yyyyMMddHHmmss * @return */ public static String getDateTimeCompactToNormal(String DateString){ StringBuilder sb = new StringBuilder(); sb.append(DateString.substring(0,4)).append("-").append(DateString.subSequence(4, 6)).append("-").append(DateString.substring(6, 8)) .append(" ").append(DateString.substring(8, 10)).append(":").append(DateString.substring(10, 12)).append(":").append(DateString.substring(12)); return sb.toString(); } /** * Convert the time input in the interface into an intermittent time string* 2010-12-02 10:14:23 Time formatted as 20101202101423 * @param dateNormalStr String * @return String */ public static String getCompactString(String dateNormalStr) { StringBuffer ret = new StringBuffer(); try { ret.append(dateNormalStr.substring(0, 4)); ret.append(dateNormalStr.substring(5, 7)); ret.append(dateNormalStr.substring(8, 10)); ret.append(dateNormalStr.substring(11, 13)); ret.append(dateNormalStr.substring(14, 16)); ret.append(dateNormalStr.substring(17, 19)); } catch (Exception ex) { // If the string is not long enough, return the previous part} return ret.toString(); } /** * Get the year in the 20101202(101423) time format* @param DateString Time format:yyyyMMdd(HHmmss) * @return */ public static String getYear(String DateString){ return DateString.substring(0,4); } /** * Get the month with the 20101202(101423) time format * @param DateString Time format: yyyyMMdd(HHmmss) * @return */ public static String getMonth(String DateString){ return DateString.substring(4,6); } /** * Get the date with the 20101202 time format * @param DateString Time format: yyyyMMdd * @return */ public static String getDayNoTime(String DateString){ return DateString.substring(6); } /** * Get the date before the current date and push forward by the number of days* @param numVal * @param dateFormat * @return * @author wul * 2016-1-17 */ public static String getBeforeDatePlusDay(int numVal, String dateFormat) { Calendar calendar = Calendar.getInstance(); long currentTimeMillis = calendar.getTimeInMillis(); long hourInMillis = 60 * 60 * 1000; long dVal = numVal * 24 * hourInMillis; SimpleDateFormat sdf = new SimpleDateFormat(dateFormat); String currentDate = sdf.format(currentTimeMillis - dVal); return currentDate; } /** * Get the date before the current date and push forward by the number of days* @param numVal * @param dateFormat * @return * @author wul * 2016-1-17 */ public static String getAfterDatePlusDay(int numVal, String dateFormat) { Calendar calendar = Calendar.getInstance(); long currentTimeMillis = calendar.getTimeInMillis(); long hourInMillis = 60 * 60 * 1000; long dVal = numVal * 24 * hourInMillis; SimpleDateFormat sdf = new SimpleDateFormat(dateFormat); String currentDate = sdf.format(currentTimeMillis + dVal); return currentDate; } /** * Get the date before the current date and push forward by hour* @param numVal * @param dateFormat * @return * @author wul * 2016-1-17 */ public static String getBeforeDatePlusHour(int numVal, String dateFormat) { Calendar calendar = Calendar.getInstance(); long currentTimeMillis = calendar.getTimeInMillis(); long hourInMillis = 60 * 60 * 1000; long dVal = numVal * hourInMillis; SimpleDateFormat sdf = new SimpleDateFormat(dateFormat); String currentDate = sdf.format(currentTimeMillis - dVal); return currentDate; } /** * Get the date before the current date and push forward by hour* @param numVal * @param dateFormat * @return * @author wul * 2016-1-17 */ public static String getAfterDatePlusHour(int numVal, String dateFormat) { Calendar calendar = Calendar.getInstance(); long currentTimeMillis = calendar.getTimeInMillis(); long hourInMillis = 60 * 60 * 1000; long dVal = numVal * hourInMillis; SimpleDateFormat sdf = new SimpleDateFormat(dateFormat); String currentDate = sdf.format(currentTimeMillis + dVal); return currentDate; } /** * Number of days different between two dates* @param beginDate * @param endDate * @return * @author wul * 2016-1-18 */ public static int daysBetween(Date beginDate, Date endDate) { Calendar cal = Calendar.getInstance(); cal.setTime(beginDate); long time1 = cal.getTimeInMillis(); cal.setTime(endDate); long time2 = cal.getTimeInMillis(); long between_days = (time2 - time1) / (1000 * 3600 * 24); return Integer.parseInt(String.valueOf(between_days)); } /** * Get the number of days in a certain month* @param year * @param month * @return * @author wul * 2016-1-18 */ public static int getMonthdays(int year, int month) { Calendar cal = Calendar.getInstance(); cal.set(Calendar.YEAR, year); cal.set(Calendar.MONTH, month - 1); return cal.getActualMaximum(Calendar.DATE); } /** * Add or subtract the year to time* @param date * @param plusTime * @return * @author wul * 2016-1-18 */ public static Date getDatePlusYear(Date date, int plusTime) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.add(Calendar.YEAR, plusTime); Date d = cal.getTime(); return d; } /** * Add or subtract the month of time* @param date * @param plusTime * @return * @author wul * 2016-1-18 */ public static Date getDatePlusMonth(Date date, int plusTime) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.add(Calendar.MONTH, plusTime); Date d = cal.getTime(); return d; } /** * Add and subtract the number of days to time* @param date * @param plusTime * @return * @author wul * 2016-1-18 */ public static Date getDatePlusDay(Date date, int plusTime) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.add(Calendar.DATE, plusTime); Date d = cal.getTime(); return d; } /** * Add or subtract time* @param date * @param plusTime * @return * @author wul * 2016-1-18 */ public static Date getDatePlusHour(Date date, int plusTime) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.add(Calendar.HOUR, plusTime); Date d = cal.getTime(); return d; } /** * Add or subtract time* @param date * @param plusTime * @return * @author wul * 2016-1-18 */ public static Date getDatePlusMinute(Date date, int plusTime) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.add(Calendar.MINUTE, plusTime); Date d = cal.getTime(); return d; } /** * Add and subtract seconds to time* @param date * @param plusTime * @return * @author wul * 2016-1-18 */ public static Date getDatePlusSecond(Date date, int plusTime) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.add(Calendar.SECOND, plusTime); Date d = cal.getTime(); return d; } /** * Return the current year* @return * @author wul * 2016-1-18 */ public static int getCurrentYear() { Calendar calendar = Calendar.getInstance(); return calendar.get(1); } /** * Return the current month* @return * @author wul * 2016-1-18 */ public static int getCurrentMonth() { Calendar calendar = Calendar.getInstance(); return calendar.get(2) + 1; } /** * Return the current day* @return * @author wul * 2016-1-18 */ public static int getCurrentDay() { Calendar calendar = Calendar.getInstance(); return calendar.get(5); } /** * Return the current hour* @return * @author wul * 2016-1-18 */ public static int getCurrentHour() { Calendar calendar = Calendar.getInstance(); return calendar.get(11); } /** * Return the current minute* @return * @author wul * 2016-1-18 */ public static int getCurrentMinute() { Calendar calendar = Calendar.getInstance(); return calendar.get(12); } /** * Return the current second* @return * @author wul * 2016-1-18 */ public static int getCurrentSecond() { Calendar calendar = Calendar.getInstance(); return calendar.get(13); } /** * Return the current year* @return * @author wul * 2016-1-18 */ public static int getYear(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(1); } /** * Return the current month* @return * @author wul * 2016-1-18 */ public static int getMonth(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(2) + 1; } /** * Return the current day* @return * @author wul * 2016-1-18 */ public static int getDay(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(5); } /** * Return the current hour* @return * @author wul * 2016-1-18 */ public static int getHour(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(11); } /** * Return the current minute* @return * @author wul * 2016-1-18 */ public static int getMinute(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(12); } /** * Return the current second* @return * @author wul * 2016-1-18 */ public static int getSecond(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(13); } public static void main(String[] args) { System.out.println(DateUtil.dateToString(new java.sql.Date(System.currentTimeMillis()), DateUtil.DATE_NORMAL_FORMAT)); Map<String,Object> map = new HashMap<String,Object>(); map.put("date", new Date()); String json = JSONObject.fromObject(map).toString(); System.out.println(json); }}The above is all the content of this article. 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