java获得毫秒 ：System.currentTimeMillis() java获得纳秒 ：System.nanoTime() (用于获取很精确的时间，推荐！) java获得当前日期： GregorianCalendar date_1=(GregorianCalendar)Calendar.getInstance(); java.sql.Date date_2= new java.sql.Date(date_1.getTime().getTime()); ---------------------------------------------------------------------------------------import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; public class DateTest { public static void main(String[] args) throws ParseException { Calendar now = Calendar.getInstance(); System.out.println("年: " + now.get(Calendar.YEAR)); System.out.println("月: " + (now.get(Calendar.MONTH) + 1)); System.out.println("日: " + now.get(Calendar.DAY_OF_MONTH)); System.out.println("时: " + now.get(Calendar.HOUR_OF_DAY)); System.out.println("分: " + now.get(Calendar.MINUTE)); System.out.println("秒: " + now.get(Calendar.SECOND)); System.out.println("当前时间毫秒数：" + now.getTimeInMillis()); System.out.println(now.getTime()); Date d = new Date(); System.out.println(d); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss"); String dateNowStr = sdf.format(d); System.out.println("格式化后的日期：" + dateNowStr); String str = "2012-08-20 17:52:07"; //要跟上面定义的格式一样 Date today = sdf.parse(str); System.out.println("字符串转成日期：" + today); } } 输出结果：年: 2012月: 8日: 20时: 17分: 53秒: 46当前时间毫秒数：1345456426312Mon Aug 20 17:53:46 CST 2012Mon Aug 20 17:53:46 CST 2012格式化后的日期：2012-08-20 17:53:46字符串转成日期：Mon Aug 20 17:52:07 CST 2012---------------------------------------------------------------------------------------import java.text.DateFormat; import java.text.ParsePosition; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; public class TimeTest { //用来全局控制 上一周，本周，下一周的周数变化 private int weeks = 0; private int MaxDate;//一月最大天数 private int MaxYear;//一年最大天数 public static void main(String[] args) { TimeTest tt = new TimeTest(); System.out.println("获取当天日期:"+tt.getNowTime("yyyy-MM-dd")); System.out.println("获取本周一日期:"+tt.getMondayOFWeek()); System.out.println("获取本周日的日期:"+tt.getCurrentWeekday()); System.out.println("获取上周一日期:"+tt.getPreviousWeekday()); System.out.println("获取上周日日期:"+tt.getPreviousWeekSunday()); System.out.println("获取下周一日期:"+tt.getNextMonday()); System.out.println("获取下周日日期:"+tt.getNextSunday()); System.out.println("获得相应周的周六的日期:"+tt.getNowTime("yyyy-MM-dd")); System.out.println("获取本月第一天日期:"+tt.getFirstDayOfMonth()); System.out.println("获取本月最后一天日期:"+tt.getDefaultDay()); System.out.println("获取上月第一天日期:"+tt.getPreviousMonthFirst()); System.out.println("获取上月最后一天的日期:"+tt.getPreviousMonthEnd()); System.out.println("获取下月第一天日期:"+tt.getNextMonthFirst()); System.out.println("获取下月最后一天日期:"+tt.getNextMonthEnd()); System.out.println("获取本年有多少天:"+tt.getMaxYear()); System.out.println("获取本年的第一天日期:"+tt.getCurrentYearFirst()); System.out.println("获取本年最后一天日期:"+tt.getCurrentYearEnd()); System.out.println("获取去年的第一天日期:"+tt.getPreviousYearFirst()); System.out.println("获取去年的最后一天日期:"+tt.getPreviousYearEnd()); System.out.println("获取明年第一天日期:"+tt.getNextYearFirst()); System.out.println("获取明年最后一天日期:"+tt.getNextYearEnd()); System.out.println("获取本季度第一天到最后一天:"+tt.getThisSeasonTime(11)); System.out.println("获取两个日期之间间隔天数2011-12-1~2012-7.29:"+TimeTest.getTwoDay("2012-7-29","2011-12-1")); } /** * 得到二个日期间的间隔天数 */ public static String getTwoDay(String sj1, String sj2) { SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd"); long day = 0; try { java.util.Date date = myFormatter.parse(sj1); java.util.Date mydate = myFormatter.parse(sj2); day = (date.getTime() - mydate.getTime()) / (24 * 60 * 60 * 1000); } catch (Exception e) { return ""; } return day + ""; } /** * 根据一个日期，返回是星期几的字符串 */ public static String getWeek(String sdate) { // 再转换为时间 Date date = TimeTest.strToDate(sdate); Calendar c = Calendar.getInstance(); c.setTime(date); // int hour=c.get(Calendar.DAY_OF_WEEK); // hour中存的就是星期几了，其范围 1~7 // 1=星期日 7=星期六，其他类推 return new SimpleDateFormat("EEEE").format(c.getTime()); } /** * 将短时间格式字符串转换为时间 yyyy-MM-dd */ public static Date strToDate(String strDate) { SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); ParsePosition pos = new ParsePosition(0); Date strtodate = formatter.parse(strDate, pos); return strtodate; } /** * 两个时间之间的天数 */ public static long getDays(String date1, String date2) { if (date1 == null || date1.equals("")) return 0; if (date2 == null || date2.equals("")) return 0; // 转换为标准时间 SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd"); java.util.Date date = null; java.util.Date mydate = null; try { date = myFormatter.parse(date1); mydate = myFormatter.parse(date2); } catch (Exception e) { } long day = (date.getTime() - mydate.getTime()) / (24 * 60 * 60 * 1000); return day; } // 计算当月最后一天,返回字符串 public String getDefaultDay(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.set(Calendar.DATE,1);//设为当前月的1号 lastDate.add(Calendar.MONTH,1);//加一个月，变为下月的1号 lastDate.add(Calendar.DATE,-1);//减去一天，变为当月最后一天 str=sdf.format(lastDate.getTime()); return str; } // 上月第一天 public String getPreviousMonthFirst(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.set(Calendar.DATE,1);//设为当前月的1号 lastDate.add(Calendar.MONTH,-1);//减一个月，变为下月的1号 //lastDate.add(Calendar.DATE,-1);//减去一天，变为当月最后一天 str=sdf.format(lastDate.getTime()); return str; } //获取当月第一天 public String getFirstDayOfMonth(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.set(Calendar.DATE,1);//设为当前月的1号 str=sdf.format(lastDate.getTime()); return str; } // 获得本周星期日的日期 public String getCurrentWeekday() { weeks = 0; int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus+6); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } //获取当天时间 public String getNowTime(String dateformat){ Date now = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat(dateformat);//可以方便地修改日期格式 String hehe = dateFormat.format(now); return hehe; } // 获得当前日期与本周日相差的天数 private int getMondayPlus() { Calendar cd = Calendar.getInstance(); // 获得今天是一周的第几天，星期日是第一天，星期二是第二天...... int dayOfWeek = cd.get(Calendar.DAY_OF_WEEK)-1; //因为按中国礼拜一作为第一天所以这里减1 if (dayOfWeek == 1) { return 0; } else { return 1 - dayOfWeek; } } //获得本周一的日期 public String getMondayOFWeek(){ weeks = 0; int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } //获得相应周的周六的日期 public String getSaturday() { int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 * weeks + 6); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } // 获得上周星期日的日期 public String getPreviousWeekSunday() { weeks=0; weeks--; int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus+weeks); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } // 获得上周星期一的日期 public String getPreviousWeekday() { weeks--; int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 * weeks); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } // 获得下周星期一的日期 public String getNextMonday() { weeks++; int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus + 7); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } // 获得下周星期日的日期 public String getNextSunday() { int mondayPlus = this.getMondayPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE, mondayPlus + 7+6); Date monday = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preMonday = df.format(monday); return preMonday; } private int getMonthPlus(){ Calendar cd = Calendar.getInstance(); int monthOfNumber = cd.get(Calendar.DAY_OF_MONTH); cd.set(Calendar.DATE, 1);//把日期设置为当月第一天 cd.roll(Calendar.DATE, -1);//日期回滚一天，也就是最后一天 MaxDate=cd.get(Calendar.DATE); if(monthOfNumber == 1){ return -MaxDate; }else{ return 1-monthOfNumber; } } //获得上月最后一天的日期 public String getPreviousMonthEnd(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.add(Calendar.MONTH,-1);//减一个月 lastDate.set(Calendar.DATE, 1);//把日期设置为当月第一天 lastDate.roll(Calendar.DATE, -1);//日期回滚一天，也就是本月最后一天 str=sdf.format(lastDate.getTime()); return str; } //获得下个月第一天的日期 public String getNextMonthFirst(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.add(Calendar.MONTH,1);//减一个月 lastDate.set(Calendar.DATE, 1);//把日期设置为当月第一天 str=sdf.format(lastDate.getTime()); return str; } //获得下个月最后一天的日期 public String getNextMonthEnd(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.add(Calendar.MONTH,1);//加一个月 lastDate.set(Calendar.DATE, 1);//把日期设置为当月第一天 lastDate.roll(Calendar.DATE, -1);//日期回滚一天，也就是本月最后一天 str=sdf.format(lastDate.getTime()); return str; } //获得明年最后一天的日期 public String getNextYearEnd(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.add(Calendar.YEAR,1);//加一个年 lastDate.set(Calendar.DAY_OF_YEAR, 1); lastDate.roll(Calendar.DAY_OF_YEAR, -1); str=sdf.format(lastDate.getTime()); return str; } //获得明年第一天的日期 public String getNextYearFirst(){ String str = ""; SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd"); Calendar lastDate = Calendar.getInstance(); lastDate.add(Calendar.YEAR,1);//加一个年 lastDate.set(Calendar.DAY_OF_YEAR, 1); str=sdf.format(lastDate.getTime()); return str; } //获得本年有多少天 private int getMaxYear(){ Calendar cd = Calendar.getInstance(); cd.set(Calendar.DAY_OF_YEAR,1);//把日期设为当年第一天 cd.roll(Calendar.DAY_OF_YEAR,-1);//把日期回滚一天。 int MaxYear = cd.get(Calendar.DAY_OF_YEAR); return MaxYear; } private int getYearPlus(){ Calendar cd = Calendar.getInstance(); int yearOfNumber = cd.get(Calendar.DAY_OF_YEAR);//获得当天是一年中的第几天 cd.set(Calendar.DAY_OF_YEAR,1);//把日期设为当年第一天 cd.roll(Calendar.DAY_OF_YEAR,-1);//把日期回滚一天。 int MaxYear = cd.get(Calendar.DAY_OF_YEAR); if(yearOfNumber == 1){ return -MaxYear; }else{ return 1-yearOfNumber; } } //获得本年第一天的日期 public String getCurrentYearFirst(){ int yearPlus = this.getYearPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE,yearPlus); Date yearDay = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preYearDay = df.format(yearDay); return preYearDay; } //获得本年最后一天的日期 * public String getCurrentYearEnd(){ Date date = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");//可以方便地修改日期格式 String years = dateFormat.format(date); return years+"-12-31"; } //获得上年第一天的日期 * public String getPreviousYearFirst(){ Date date = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");//可以方便地修改日期格式 String years = dateFormat.format(date); int years_value = Integer.parseInt(years); years_value--; return years_value+"-1-1"; } //获得上年最后一天的日期 public String getPreviousYearEnd(){ weeks--; int yearPlus = this.getYearPlus(); GregorianCalendar currentDate = new GregorianCalendar(); currentDate.add(GregorianCalendar.DATE,yearPlus+MaxYear*weeks+(MaxYear-1)); Date yearDay = currentDate.getTime(); DateFormat df = DateFormat.getDateInstance(); String preYearDay = df.format(yearDay); getThisSeasonTime(11); return preYearDay; } //获得本季度 public String getThisSeasonTime(int month){ int array[][] = {{1,2,3},{4,5,6},{7,8,9},{10,11,12}}; int season = 1; if(month>=1&&month<=3){ season = 1; } if(month>=4&&month<=6){ season = 2; } if(month>=7&&month<=9){ season = 3; } if(month>=10&&month<=12){ season = 4; } int start_month = array[season-1][0]; int end_month = array[season-1][2]; Date date = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");//可以方便地修改日期格式 String years = dateFormat.format(date); int years_value = Integer.parseInt(years); int start_days =1;//years+"-"+String.valueOf(start_month)+"-1";//getLastDayOfMonth(years_value,start_month); int end_days = getLastDayOfMonth(years_value,end_month); String seasonDate = years_value+"-"+start_month+"-"+start_days+";"+years_value+"-"+end_month+"-"+end_days; return seasonDate; } /** * 获取某年某月的最后一天 * @param year 年 * @param month 月 * @return 最后一天 */ private int getLastDayOfMonth(int year, int month) { if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) { return 31; } if (month == 4 || month == 6 || month == 9 || month == 11) { return 30; } if (month == 2) { if (isLeapYear(year)) { return 29; } else { return 28; } } return 0; } /** * 是否闰年 * @param year 年 * @return */ public boolean isLeapYear(int year) { return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0); } }
