Java Date 日期 时间 相关方法
DateTools.java
import java.text.SimpleDateFormat; import java.util.Date; /** * 日期操作类 */ public class DateTools { /**yyyyMMddHHmmss * * @return */ public static String getAllDate(){ SimpleDateFormat lFormat; //格式可以自己根据需要修改 lFormat = new SimpleDateFormat("yyyyMMddHHmmss"); String gRtnStr = lFormat.format(new Date()); return gRtnStr; } /** * 获得yymmdd类型的日期 * @param date * @return */ public static String getDateString(Date date){ String year =(date.getYear()+1900)+""; String mm = (date.getMonth()+1)+""; if(Integer.valueOf(mm).intValue()<10){ mm="0"+mm; } String day = date.getDate()+""; if(Integer.valueOf(day).intValue()<10)day="0"+day; return year+mm+day; } /** * 获得yymmdd类型的日期(日期的前1天) * @param date * @return */ public static String getZDateString(Date date){ date.setDate(date.getDate()-1); String year =(date.getYear()+1900)+""; String mm = (date.getMonth()+1)+""; if(Integer.valueOf(mm).intValue()<10){ mm="0"+mm; } String day = date.getDate()+""; if(day.length()==1)day="0"+day; return year+mm+day; } /** * 获得yy-mm-dd类型的日期 * @param date * @return */ public static String DateString(Date date){ String year =(date.getYear()+1900)+""; String mm = (date.getMonth()+1)+""; if(Integer.valueOf(mm).intValue()<10){ mm="0"+mm; } String day = date.getDate()+""; if(day.length()==1){ day="0"+day; } return year+"-"+mm+"-"+day; } //得到当前时间 public static String getCurrentDateTime() { java.text.SimpleDateFormat d = new java.text.SimpleDateFormat(); d.applyPattern("HH:mm:ss"); java.util.Date nowdate = new java.util.Date(); String str_date = d.format(nowdate); return str_date; } /** * 时间格式化 * @return */ public static String getTimeString(String time){ String[] ti = time.split(":"); if(ti[1].length()==1){ time = ti[0]+"0"+ti[1]; }else{ time = ti[0]+ti[1]; } return time; } public static String TimeString(){ Date date = new Date(); return getTimeString(date.getHours()+":"+date.getMinutes()); } public static void main(String args[]){ System.out.println(DateTools.getZDateString(new Date())); } }
DateTime.java
import java.util.*; import java.text.*; public class DateTime { public DateTime() { } public static final long SECOND = 1000; public static final long MINUTE = 60 * SECOND; public static final long HOUR = 60 * MINUTE; public static final long DAY = 24 * HOUR; public static final long WEEK = 7 * DAY; public static final String SHORTFORMAT = "yyyy-MM-dd"; public static final String SHORTFORMATNOSPIT = "yyyyMMdd"; public static final String YEARMONTHFORMAT = "yyyy-MM"; public static final String LONGFORMAT = "yyyy-MM-dd HH:mm:ss"; /** * 获得yymmdd类型的日期 * @param date * @return */ public static String getDateString(Date date){ String year =(date.getYear()+1900)+""; String mm = (date.getMonth()+1)+""; if(Integer.valueOf(mm).intValue()<10){ mm="0"+mm; } String day = date.getDate()+""; return year+mm+day; } /** * 获得yy-mm-dd类型的日期 * @param date * @return */ public static String DateString(Date date){ String year =(date.getYear()+1900)+""; String mm = (date.getMonth()+1)+""; if(Integer.valueOf(mm).intValue()<10){ mm="0"+mm; } String day = date.getDate()+""; if(day.length()==1){ day="0"+day; } return year+"-"+mm+"-"+day; } // 得到某一天是星期几 public static int getDateInWeek(String strDate) { DateFormat df = DateFormat.getDateInstance(); try { df.parse(strDate); java.util.Calendar c = df.getCalendar(); int day = c.get(Calendar.DAY_OF_WEEK) - Calendar.SUNDAY; return day; } catch (ParseException e) { return -1; } } //得到当前日期 public static String getCurrentDate() { java.text.SimpleDateFormat d = new java.text.SimpleDateFormat(); d.applyPattern("yyyy-MM-dd"); java.util.Date nowdate = new java.util.Date(); String str_date = d.format(nowdate); return str_date; } //得到当前日期时间 public static String getCurrentDateTime() { java.text.SimpleDateFormat d = new java.text.SimpleDateFormat(); d.applyPattern("yyyy-MM-dd HH:mm:ss"); java.util.Date nowdate = new java.util.Date(); String str_date = d.format(nowdate); return str_date; } //根据日期获得日期时间 public static String getDateTime(java.util.Date date) { java.text.SimpleDateFormat d = new java.text.SimpleDateFormat(); d.applyPattern("yyyy-MM-dd HH:mm:ss"); String str_date = d.format(date); return str_date; } //获得某月的最后一天 public static int getDayNum(int year, int month) { if (month == 2) { return year % 400 != 0 && (year % 4 != 0 || year % 100 == 0) ? 28 : 29; } String SmallMonth = ",4,6,9,11,"; return SmallMonth.indexOf(String.valueOf(String .valueOf((new StringBuffer(",")).append(String.valueOf(month)) .append(",")))) < 0 ? 31 : 30; } //返回两个日期之间隔了多少天 public static int DateDiff(Date date1, Date date2) { int i = (int) ( (date1.getTime() - date2.getTime()) / 3600 / 24 / 1000); return i; } //从放有日期的字符串中得到，相应的年，月，日 style is "Y"or"y" 返回年 style is "M"or"m" 返回月 style //is "D"or"d" 返回日 日期字符串要求 "YYYY-MM-DD" public static int getYearMonthDate(String strDate, String style) { int year; int month; int day; int firstDash; int secondDash; if (strDate == null) { return 0; } firstDash = strDate.indexOf('-'); secondDash = strDate.indexOf('-', firstDash + 1); if ((firstDash > 0) & (secondDash > 0) & (secondDash < strDate.length() - 1)) { year = Integer.parseInt(strDate.substring(0, firstDash)); month = Integer.parseInt(strDate.substring(firstDash + 1, secondDash)); day = Integer.parseInt(strDate.substring(secondDash + 1)); } else { return 0; } if (style.equalsIgnoreCase("Y")) { return year; } else if (style.equalsIgnoreCase("M")) { return month; } else if (style.equalsIgnoreCase("D")) { return day; } else { return 0; } } // 某一天，过几天后是几号 public static java.sql.Date DateAdd(java.sql.Date date, int addday) { java.sql.Date datenew = null; int year = DateTime.getYearMonthDate(date.toString(), "Y"); int month = DateTime.getYearMonthDate(date.toString(), "M"); int day = DateTime.getYearMonthDate(date.toString(), "D"); day = day + addday; String dayStr = Integer.toString(year) + "-" + Integer.toString(month) + "-" + Integer.toString(day); datenew = datenew.valueOf(dayStr); //datenew.setTime(datenew.getTime()+day*3600*24*1000); //有问题。 改 return datenew; } //某一天的前几天是几号 public static java.sql.Date DateBefore(java.sql.Date date, int addday) { java.sql.Date datenew = null; int year = DateTime.getYearMonthDate(date.toString(), "Y"); int month = DateTime.getYearMonthDate(date.toString(), "M"); int day = DateTime.getYearMonthDate(date.toString(), "D"); day = day - addday; String dayStr = Integer.toString(year) + "-" + Integer.toString(month) + "-" + Integer.toString(day); datenew = datenew.valueOf(dayStr); // datenew.setTime(datenew.getTime()+day*3600*24*1000); // 有问题。 改 return datenew; } //某一天是否是年的头一天 public static boolean isYearFirstDay(java.sql.Date date) { boolean i = false; if ((DateTime.getYearMonthDate(date.toString(), "M") == 1) && (DateTime.getYearMonthDate(date.toString(), "D") == 1)) { i = true; } return i; } // 某一天是否是半年的头一天 public static boolean isHalfYearFirstDay(java.sql.Date date) { boolean i = false; if (((DateTime.getYearMonthDate(date.toString(), "M") == 1) && (DateTime .getYearMonthDate(date.toString(), "D") == 1)) || ((DateTime.getYearMonthDate(date.toString(), "M") == 7) && (DateTime .getYearMonthDate(date.toString(), "D") == 1))) { i = true; } return i; } public static String getHalfYearFirstDay(java.sql.Date date) { String month = "01"; if (DateTime.getYearMonthDate(date.toString(), "M") >= 7) { month = "07"; } String day = Integer.toString(DateTime.getYearMonthDate(date .toString(), "Y")) + "-" + month + "-01"; return day; } // 某一天是否是半年的最后一天 public static boolean isHalfYearLastDay(java.sql.Date date) { boolean i = false; if (((DateTime.getYearMonthDate(date.toString(), "M") == 12) && (DateTime .getYearMonthDate(date.toString(), "D") == 31)) || ((DateTime.getYearMonthDate(date.toString(), "M") == 6) && (DateTime .getYearMonthDate(date.toString(), "D") == 30))) { i = true; } return i; } public static String getHalfYearLastDay(java.sql.Date date) { String month = "-06-30"; if (DateTime.getYearMonthDate(date.toString(), "M") >= 7) { month = "-12-31"; } String day = Integer.toString(getYearMonthDate(date.toString(), "Y")) + "-" + month; return day; } // 某一天是否是年的最后一天 public static boolean isYearLastDay(java.sql.Date date) { boolean i = false; if ((DateTime.getYearMonthDate(date.toString(), "M") == 12) && (DateTime.getYearMonthDate(date.toString(), "D") == 31)) { i = true; } return i; } //某一天是否是季的头一天 public static boolean isQuarterFirstDay(java.sql.Date date) { boolean i = false; if (((DateTime.getYearMonthDate(date.toString(), "M") == 1) || (DateTime.getYearMonthDate(date.toString(), "M") == 4) || (DateTime.getYearMonthDate(date.toString(), "M") == 7) || (DateTime .getYearMonthDate(date.toString(), "M") == 10)) && (DateTime.getYearMonthDate(date.toString(), "D") == 1)) { i = true; } return i; } public static String getQuarterFirstDay(java.sql.Date date) { String month = "01"; if (DateTime.getYearMonthDate(date.toString(), "M") >= 10) { month = "10"; } else if (DateTime.getYearMonthDate(date.toString(), "M") >= 7) { month = "07"; } else if (DateTime.getYearMonthDate(date.toString(), "M") >= 4) { month = "04"; } else if (DateTime.getYearMonthDate(date.toString(), "M") >= 1) { month = "01"; } String day = Integer.toString(DateTime.getYearMonthDate(date .toString(), "Y")) + "-" + month + "-01"; return day; } //某一天是否是季的最后一天 public static boolean isQuarterLastDay(java.sql.Date date) { boolean i = false; if ((DateTime.getYearMonthDate(date.toString(), "M") == 3) && (DateTime.getYearMonthDate(date.toString(), "D") == 31)) { i = true; } if ((DateTime.getYearMonthDate(date.toString(), "M") == 6) && (DateTime.getYearMonthDate(date.toString(), "D") == 30)) { i = true; } if ((DateTime.getYearMonthDate(date.toString(), "M") == 9) && (DateTime.getYearMonthDate(date.toString(), "D") == 30)) { i = true; } if ((DateTime.getYearMonthDate(date.toString(), "M") == 12) && (DateTime.getYearMonthDate(date.toString(), "D") == 31)) { i = true; } return i; } public static String getQuarterLastDay(java.sql.Date date) { String month = "-01-31"; if (DateTime.getYearMonthDate(date.toString(), "M") >= 10) { month = "-12-31"; } else if (DateTime.getYearMonthDate(date.toString(), "M") >= 7) { month = "-09-30"; } else if (DateTime.getYearMonthDate(date.toString(), "M") >= 4) { month = "-06-30"; } String day = Integer.toString(DateTime.getYearMonthDate(date .toString(), "Y")) + "-" + month; return day; } //某一天是否是月的最后一天 public static boolean isMonthLastDay(java.sql.Date date) { boolean i = false; java.sql.Date des_date = null; String month; String str_date = date.toString(); String year = str_date.substring(0, str_date.indexOf("-")); int m = new Integer(str_date.substring(str_date.indexOf("-") + 1, str_date.lastIndexOf("-"))).intValue() + 1; month = new Integer(m).toString(); if (m < 10) { month = "0" + month; } java.sql.Date mid_date = null; mid_date = mid_date.valueOf(year + "-" + month + "-01"); des_date = DateTime.DateAdd(mid_date, -1); if (DateTime.DateDiff(des_date, date) == 0) { i = true; } return i; } //某一天是否是月的第一天 public static boolean isMonthFisrtDay(java.sql.Date date) { boolean i = false; if ((DateTime.getYearMonthDate(date.toString(), "D") == 1)) { i = true; } return i; } //获得月的第一天 public static String getMonthFisrtDay(java.sql.Date date) { String month; if (DateTime.getYearMonthDate(date.toString(), "M") > 9) { month = Integer.toString(DateTime.getYearMonthDate(date .toString(), "M")); } else { month = "0" + Integer.toString(DateTime.getYearMonthDate(date .toString(), "M")); } String day = Integer.toString(DateTime.getYearMonthDate(date .toString(), "Y")) + "-" + month + "-01"; return day; } public static java.sql.Timestamp getTimestamp() { try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss"); java.util.Calendar calendar = java.util.Calendar.getInstance(); String mystrdate = myFormat.format(calendar.getTime()); return java.sql.Timestamp.valueOf(mystrdate); } catch (Exception e) { return null; } } public static java.sql.Timestamp getTimestamp(String datestr) { try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss"); String mystrdate = myFormat.format(myFormat.parse(datestr)); return java.sql.Timestamp.valueOf(mystrdate); } catch (Exception e) { return null; } } //格式化日期（Y-年，M-月,D-日 HH:mm:ss 小时：分钟：秒） public static String getDate(java.util.Date date, String format) { String result = null; try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat(format); result = myFormat.format(date); } catch (Exception e) { return null; } return result; } public static String getDate(java.util.Date date) { return getDate(date, LONGFORMAT); } //转换成时间戳 public static java.sql.Timestamp getDate(String datestr) { try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat( "yyyy-MM-dd"); Date date = myFormat.parse(datestr); myFormat.applyLocalizedPattern("yyyy-MM-dd HH:mm:ss"); String mystrdate = myFormat.format(date); return java.sql.Timestamp.valueOf(mystrdate); } catch (Exception e) { return null; } } //将日期格式化成yyyy-MM-dd形式 public static java.util.Date format(String datestr) { try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat( "yyyy-MM-dd"); Date date = myFormat.parse(datestr); return date; } catch (Exception e) { return new Date(datestr); } } //格式化日期（Y-年，M-月,D-日 HH:mm:ss 小时：分钟：秒） public static java.util.Date format(String datestr, String format) { try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat(format); Date date = myFormat.parse(datestr); return date; } catch (Exception e) { return null; } } //获得数据库格式的日期 public static java.sql.Date getSqlDate(java.util.Date date) { java.sql.Date result = null; try { java.text.SimpleDateFormat myFormat = new SimpleDateFormat( "yyyy-MM-dd"); String mystrdate = myFormat.format(date); result = java.sql.Date.valueOf(mystrdate); } catch (Exception e) { return null; } return result; } public static java.util.Date addMonth(java.util.Date date, int month) { String strdate = getDate(date, SHORTFORMAT); int curmonth = Integer.parseInt(strdate.substring(5, 7)); int year = Integer.parseInt(strdate.substring(0, 4)); int addyear = month / 12; year = year + addyear; curmonth = curmonth + (month % 12); if (curmonth > 12) { curmonth = 1; year = year + 1; } String strmonth = String.valueOf(curmonth); if (strmonth.length() == 1) { strmonth = "0" + strmonth; } strdate = String.valueOf(year) + "-" + strmonth + "-" + strdate.substring(8, 10); return format(strdate, SHORTFORMAT); } /** * 传递日期， 获得上个月的最后1天 * @param dt * @return */ public static String getUpMDate(Date dt){ dt.setDate(1); dt.setDate(dt.getDate()-1); return dt.toLocaleString(); } /** *得到当前是那一天。 * */ public static String getDate() { java.text.SimpleDateFormat d = new java.text.SimpleDateFormat(); d.applyPattern("yyyy-MM-dd"); java.util.Date nowdate = new java.util.Date(); String str_date = d.format(nowdate); return str_date; } /** * 将10位日期格式化为8位 * @param dt * @return */ public static String getShortDate(String dt){ if(dt != null){ java.text.SimpleDateFormat myFormat = new SimpleDateFormat("yyyy-MM-dd"); try { Date date = myFormat.parse(dt); return getDate(date,SHORTFORMATNOSPIT); } catch (ParseException e) { return dt; } }else return dt; } /** * 将8位日期格式化为10位 * @param dt * @return */ public static String getLongDate(String dt){ if(dt != null){ java.text.SimpleDateFormat myFormat = new SimpleDateFormat("yyyyMMdd"); try { Date date = myFormat.parse(dt); return getDate(date,SHORTFORMAT); } catch (ParseException e) { return dt; } }else return dt; } /** * 判断是否是当月 * @param month * @return */ public static boolean isSameYearMonth(String date){ try{ String currdate = getCurrentDate(); currdate = getShortDate(currdate).substring(0,6); String lastdate = getShortDate(date).substring(0,6); if(lastdate.equals(currdate)){ return true; }else{ return false; } }catch(NumberFormatException e){ return false; } } public static void main(String[] args){ Date d = new Date("20070829"); Date f = new Date("20070912"); System.out.println(d.getDate()-f.getDate()); } }
这几天一直在处理Java的日期问题，通常需要按要求生成日期的话，通常会用到util包中的Calendar类，再用Calendar的getTime()方法生成对应的Date，最后用SimpleDateFormat输出。
1. 获取当期日期、年份、月份
import java.util.Calendar;
public class Main { public static void main(String[] args) { Calendar now = Calendar.getInstance(); System.out.println("Current Year is : " + now.get(Calendar.YEAR)); // month start from 0 to 11 System.out.println("Current Month is : " + (now.get(Calendar.MONTH) + 1)); System.out.println("Current Date is : " + now.get(Calendar.DATE)); }}
Calendar calendar = Calendar.getInstance();//此时打印它获取的是系统当前时间
calendar.add(Calendar.DATE, -1); //得到前一天
String yestedayDate
= new SimpleDateFormat("yyyy-MM-dd").format(cal.getTime());
calendar.add(Calendar.MONTH, -1); //得到前一个月 int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH)+1; //输出前一月的时候要记得加1
3. 字符串转为日期格式
String date = "2010-02-01 23:59:59";
SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
try {
Date d = sf.parse(date);
System.out.println(sf.format(d));
} catch (ParseException e) {
e.printStackTrace();
}