Java對日期Date類進行加減運算、年份加減月份加減、時間差等等

實現代碼一：

 import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class DateTestUtil { public static void main(String[] args) throws Exception { SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd"); String str="20110823"; Date dt=sdf.parse(str); Calendar rightNow = Calendar.getInstance(); rightNow.setTime(dt); rightNow.add(Calendar.YEAR,-1);//日期減1年rightNow.add(Calendar.MONTH,3);//日期加3個月rightNow.add(Calendar.DAY_OF_YEAR,10);//日期加10天Date dt1=rightNow.getTime(); String reStr = sdf.format(dt1); System.out.println(reStr); }}

注：在Calendar對象的add方法中，第二個參數為正數表示“加”，負數表示“減”。

代碼二： java date 日期加減天數

測試類代碼：

 import java.text.SimpleDateFormat; import java.util.Date; public class DateTest { public static void main(String[] arg){ Date now = new Date(); addAndSubtractDaysByGetTime(now,-5); addAndSubtractDaysByGetTime(now,5); addAndSubtractDaysByCalendar(now,-5); addAndSubtractDaysByCalendar(now,5); } public static Date addAndSubtractDaysByGetTime(Date dateTime/*待處理的日期*/,int n/*加減天數*/){ //日期格式SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd"); SimpleDateFormat dd=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); System.out.println(df.format(new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L))); //System.out.println(dd.format(new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L))); //注意這裡一定要轉換成Long類型，要不n超過25時會出現範圍溢出，從而得不到想要的日期值return new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L); } public static Date addAndSubtractDaysByCalendar(Date dateTime/*待處理的日期*/,int n/*加減天數*/){ //日期格式SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd"); SimpleDateFormat dd=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); java.util.Calendar calstart = java.util.Calendar.getInstance(); calstart.setTime(dateTime); calstart.add(java.util.Calendar.DAY_OF_WEEK, n); System.out.println(df.format(calstart.getTime())); //System.out.println(dd.format(calstart.getTime())); return calstart.getTime(); } }

運行結果：
2014-10-06
2014-10-16
2014-10-06
2014-10-16

代碼三：

在網上查閱資料，加上自己總結的一些關於Date類的工具類。

 package com.data.utils;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class DateFormat { /** * 日期減幾年*/ public static String dateMinusYear(String str) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM"); Date dt = sdf.parse(str); Calendar rightNow = Calendar.getInstance(); rightNow.setTime(dt); rightNow.add(Calendar.YEAR, -1);// 日期減1年Date dt1 = rightNow.getTime(); String reStr = sdf.format(dt1); return reStr; } /** * 日期加幾年*/ public static String dateAddYear(String str) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM"); Date dt = sdf.parse(str); Calendar rightNow = Calendar.getInstance(); rightNow.setTime(dt); rightNow.add(Calendar.YEAR, 1);// 日期加1年Date dt1 = rightNow.getTime(); String reStr = sdf.format(dt1); return reStr; } /** * 日期減幾月*/ public static String dateMinusMonth(String str) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM"); Date dt = sdf.parse(str);//將字符串生成Date Calendar rightNow = Calendar.getInstance(); rightNow.setTime(dt);//使用給定的Date 設置此Calendar 的時間。 rightNow.add(Calendar.MONTH, -1);// 日期減1個月Date dt1 = rightNow.getTime();//返回一個表示此Calendar 時間值的Date 對象。 String reStr = sdf.format(dt1);//將給定的Date 格式化為日期/時間字符串，並將結果添加到給定的StringBuffer。 return reStr; } /** * 日期加幾月*/ public static String dateAddMonth(String str) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM"); Date dt = sdf.parse(str); Calendar rightNow = Calendar.getInstance(); rightNow.setTime(dt); rightNow.add(Calendar.MONTH, 1);// 日期加3個月// rightNow.add(Calendar.DAY_OF_YEAR,10);//日期加10天Date dt1 = rightNow.getTime(); String reStr = sdf.format(dt1); return reStr; } /** * 獲取當前年月的第一個月的str * @param str * 201505 * @return 201501 * @throws Exception */ public static String dateOneMonth(String str) { str = str.substring(0, str.length() - 2); str = str + "01"; return str; } /** * 算出所選月份距離一月份有幾個月。 * @param str 201509 * @return 9 */ public static int dateDistanceMonth(String str) { int i = Integer.parseInt(str); int j = Integer.parseInt(DateFormat.dateOneMonth(str)); System.out.println(i - j); return i - j + 1; } /** * 獲取兩個時間的時間差，精確到毫秒* @param str * @return */ public static String TimeDifference(long start, long end) { long between = end - start; long day = between / (24 * 60 * 60 * 1000); long hour = (between / (60 * 60 * 1000) - day * 24); long min = ((between / (60 * 1000)) - day * 24 * 60 - hour * 60); long s = (between / 1000 - day * 24 * 60 * 60 - hour * 60 * 60 - min * 60); long ms = (between - day * 24 * 60 * 60 * 1000 - hour * 60 * 60 * 1000 - min * 60 * 1000 - s * 1000); String timeDifference = day + "天" + hour + "小時" + min + "分" + s + "秒" + ms + "毫秒"; return timeDifference; }} /** * 獲取24小時、一周、一個月的起始時間* * @param timeInterval * : DAY_TIME_INTERVAL WEEK_TIME_INTERVAL MONTH_TIME_INTERVAL * @return "yyyy-mm-dd hh:mm:ss" */ public static String getStartTime(int timeInterval) { Calendar cal = Calendar.getInstance(); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); if (DAY_TIME_INTERVAL == timeInterval) {// 獲取24小時的起始時間cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); String startTime = sdf.format(cal.getTime()); return startTime; } else if (WEEK_TIME_INTERVAL == timeInterval) { int weekday = cal.get(Calendar.DAY_OF_WEEK) - 1; cal.add(Calendar.DATE, -weekday); cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); String startTime = sdf.format(cal.getTime()); return startTime; } else if (MONTH_TIME_INTERVAL == timeInterval) { int dayofmonthMin = cal.getActualMinimum(Calendar.DAY_OF_MONTH); // c.add(Calendar.DATE, -dayofmonth); cal.set(Calendar.DATE, dayofmonthMin); cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); String startTime = sdf.format(cal.getTime()); return startTime; } return null; } /** * 獲取24小時、一周、一個月的結束時間* * @param timeInterval * : DAY_TIME_INTERVAL WEEK_TIME_INTERVAL MONTH_TIME_INTERVAL * @return "yyyy-mm-dd hh:mm:ss" */ public static String getEndTime(int timeInterval) { Calendar cal = Calendar.getInstance(); cal.setTimeZone(TimeZone.getTimeZone("GMT+8")); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); if (DAY_TIME_INTERVAL == timeInterval) { cal.set(Calendar.HOUR_OF_DAY, 23); cal.set(12, 59); cal.set(13, 59); long date = cal.getTimeInMillis(); String endTime = sdf.format(new Date(date)); return endTime; } else if (WEEK_TIME_INTERVAL == timeInterval) { int weekday = cal.get(Calendar.DAY_OF_WEEK) - 1; cal.add(Calendar.DATE, -weekday); cal.add(Calendar.DATE, 6); cal.set(Calendar.HOUR_OF_DAY, 23); cal.set(12, 59); cal.set(13, 59); long date = cal.getTimeInMillis(); String endTime = sdf.format(new Date(date)); return endTime; } else if (MONTH_TIME_INTERVAL == timeInterval) { int dayOfMonthMax = cal.getActualMaximum(Calendar.DAY_OF_MONTH); cal.set(Calendar.DATE, dayOfMonthMax); cal.set(Calendar.HOUR_OF_DAY, 23); cal.set(Calendar.MINUTE, 59); cal.set(Calendar.SECOND, 59); String endTime = sdf.format(cal.getTime()); return endTime; } return null; } /** * 判斷dateStr是否在start和end中間，start和end都可以為null yyyyMMddHHmmss或者yyyyMMdd格式* * @author you.xu * @date 2015年8月19日下午3:11:46 * @param dateStr * @param start * @param end * @return */ public static boolean checkDateVal(String dateStr, String start, String end) { boolean isDateRight = false; Date date = null; Date startDate = null; Date endDate = null; SimpleDateFormat sdf = null; // 判斷日期格式if (14 == dateStr.length()) { sdf = new SimpleDateFormat("yyyyMMddHHmmss"); } else if (8 == dateStr.length()) { sdf = new SimpleDateFormat("yyyyMMdd"); } else return false; try { // 更改判斷日期格式date = sdf.parse(dateStr); } catch (ParseException e) { log.error(e, e); } if ((start == null) && (end != null)) { try { endDate = sdf.parse(end); } catch (ParseException ex1) { log.error(ex1, ex1); } if ((date != null) && (endDate != null))// Check parameters for { if (date.compareTo(endDate) <= 0) isDateRight = true; } } else if ((start != null) && (end == null)) { try { startDate = sdf.parse(start); } catch (ParseException ex1) { log.error(ex1, ex1); } if ((date != null) && (startDate != null)) { if (date.compareTo(startDate) >= 0) isDateRight = true; } } else if ((start != null) && (end != null)) { try { startDate = sdf.parse(start); endDate = sdf.parse(end); } catch (ParseException ex2) { System.out.println(ex2.toString()); } if ((startDate != null) && (date != null) && (endDate != null)) { if ((date.compareTo(startDate) >= 0) && (date.compareTo(endDate) <= 0)) isDateRight = true; } } return isDateRight; } /** * 判斷dateStr是否在start和end中間，start和end都可以為null long形格式* * @author you.xu * @date 2015年8月19日下午3:12:35 * @param dateStr * @param start * @param end * @return */ public static boolean checkDateV(String dateStr, String start, String end) { boolean isDateRight = false; long date = -1; long fromDate = -1; long toDate = -1; date = java.lang.Long.parseLong(dateStr); if ((start == null) && (end == null)) { isDateRight = true; } else if ((start == null) && (end != null)) { try { toDate = java.lang.Long.parseLong(end); } catch (NumberFormatException nfe) { log.error(nfe, nfe); } if (date <= toDate) { isDateRight = true; } } else if ((start != null) && (end == null)) { try { fromDate = java.lang.Long.parseLong(start); } catch (NumberFormatException nfe) { log.error(nfe, nfe); } if (date >= fromDate) { isDateRight = true; } } else if ((start != null) && (end != null)) { try { toDate = java.lang.Long.parseLong(end); fromDate = java.lang.Long.parseLong(start); } catch (NumberFormatException nfe) { log.error(nfe, nfe); } if ((date <= toDate) && (date >= fromDate)) { isDateRight = true; } } return isDateRight; }

目前就用到了這些，隨時添加，有簡單方便的時間工具類，希望和大家一起學習，在評論中指出。 thanks！ ！ ！