格式化日期 String-->Date 或者 Data-->StringSimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  Date date = sdf.parse("2009-11-04");//String-->Date  String sdate = sdf.format(date );// Data-->String ===============================================================package com.hefeng.test;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 {//用來全局控制 上一周，本周，下一周的周數變化private int weeks = 0;private int MaxDate;//一月最大天數private int MaxYear;//一年最大天數/*** @param args*/public static void main(String[] args) {TimeTest tt = new TimeTest();System.out.println("得到6個月后的日期:"+tt .getAfterMonth(6);System.out.println("獲取當天日期:"+tt.getNowTime("yyyy-MM-dd"));System.out.println("獲取本周一日期:"+tt.getMondayOFWeek());System.out.println("獲取本周日的日期~:"+tt.getCurrentWeekday());System.out.println("獲取上周一日期:"+tt.getPreviousWeekday());System.out.println("獲取上周日日期:"+tt.getPreviousWeekSunday());System.out.println("獲取下周一日期:"+tt.getNextMonday());System.out.println("獲取下周日日期:"+tt.getNextSunday());System.out.println("獲得相應周的周六:"+tt.getNowTime("yyyy-MM-dd"));System.out.println("獲取本月第一天日期:"+tt.getFirstDayOfMonth());System.out.println("獲取本月最后一天日期:"+tt.getDefaultDay());System.out.println("獲取上月第一天日期:"+tt.getPreviousMonthFirst());System.out.println("獲取上月最后一天的日期:"+tt.getPreviousMonthEnd());System.out.println("獲取下月第一天日期:"+tt.getNextMonthFirst());System.out.println("獲取下月最后一天日期:"+tt.getNextMonthEnd());System.out.println("獲取本年的第一天日期:"+tt.getCurrentYearFirst());System.out.println("獲取本年最后一天日期:"+tt.getCurrentYearEnd());System.out.println("獲取去年的第一天日期:"+tt.getPreviousYearFirst());System.out.println("獲取去年的最后一天日期:"+tt.getPreviousYearEnd());System.out.println("獲取明年第一天日期:"+tt.getNextYearFirst());System.out.println("獲取明年最后一天日期:"+tt.getNextYearEnd());System.out.println("獲取本季度第一天到最后一天:"+tt.getThisSeasonTime(11));System.out.println("獲取兩個日期之間間隔天數2008-12-1~2008-.29:"+TimeTest.getTwoDay("2008-12-1","2008-9-29"));}/*** 得到指定月后（前）的日期 參數傳負數即可*/public static String getAfterMonth(int month) {    Calendar c = Calendar.getInstance();//獲得一個日歷的實例      SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");      Date date = null;      try{        date = sdf.parse("2009-11-04");//初始日期      }catch(Exception e){     }      c.setTime(date);//設置日歷時間      c.add(Calendar.MONTH,month);//在日歷的月份上增加6個月      String strDate = sdf.format(c.getTime()));//的到你想要得6個月后的日期      return strDate; }/*** 得到二個日期間的間隔天數*/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 + "";}/*** 根據一個日期，返回是星期幾的字符串*/public static String getWeek(String sdate) {// 再轉換為時間Date date = TimeTest.strToDate(sdate);Calendar c = Calendar.getInstance();c.setTime(date);// int hour=c.get(Calendar.DAY_OF_WEEK);// hour 中存的就是星期幾了，其范圍 1~7// 1=星期日 7=星期六，其他類推return new SimpleDateFormat("EEEE").format(c.getTime());}/*** 將短時間格式字符串轉換為時間 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;}/*** 兩個時間之間的天數** @param date1* @param date2* @return*/public static long getDays(String date1, String date2) {if (date1 == null || date1.equals(""))return 0;if (date2 == null || date2.equals(""))return 0;// 轉換為標準時間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;}// 計算當月最后一天,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);//設為當前月的1 號lastDate.add(Calendar.MONTH,1);//加一個月，變為下月的1 號lastDate.add(Calendar.DATE,-1);//減去一天，變為當月最后一天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);//設為當前月的1 號lastDate.add(Calendar.MONTH,-1);//減一個月，變為下月的1 號//lastDate.add(Calendar.DATE,-1);//減去一天，變為當月最后一天str=sdf.format(lastDate.getTime());return str;}//獲取當月第一天public String getFirstDayOfMonth(){String str = "";SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");Calendar lastDate = Calendar.getInstance();lastDate.set(Calendar.DATE,1);//設為當前月的1 號str=sdf.format(lastDate.getTime());return str;}// 獲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;}//獲取當天時間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;}// 獲得當前日期與本周日相差的天數private int getMondayPlus() {Calendar cd = Calendar.getInstance();// 獲得今天是一周的第幾天，星期日是第一天，星期二是第二天......int dayOfWeek = cd.get(Calendar.DAY_OF_WEEK)-1; //因為按中國禮拜一作為第一天所以這里減1if (dayOfWeek == 1) {return 0;} else {return 1 - dayOfWeek;}}//獲得本周一的日期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;}//獲得相應周的周六的日期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;}// 獲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;}// 獲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;}// 獲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;}// 獲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);//把日期設置為當月第一天cd.roll(Calendar.DATE, -1);//日期回滾一天，也就是最后一天MaxDate=cd.get(Calendar.DATE);if(monthOfNumber == 1){return -MaxDate;}else{return 1-monthOfNumber;}}//獲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);//減一個月lastDate.set(Calendar.DATE, 1);//把日期設置為當月第一天lastDate.roll(Calendar.DATE, -1);//日期回滾一天，也就是本月最后一天str=sdf.format(lastDate.getTime());return str;}//獲得下個月第一天的日期public String getNextMonthFirst(){String str = "";SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");Calendar lastDate = Calendar.getInstance();lastDate.add(Calendar.MONTH,1);//減一個月lastDate.set(Calendar.DATE, 1);//把日期設置為當月第一天str=sdf.format(lastDate.getTime());return str;}//獲得下個月最后一天的日期public String getNextMonthEnd(){String str = "";SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");Calendar lastDate = Calendar.getInstance();lastDate.add(Calendar.MONTH,1);//加一個月lastDate.set(Calendar.DATE, 1);//把日期設置為當月第一天lastDate.roll(Calendar.DATE, -1);//日期回滾一天，也就是本月最后一天str=sdf.format(lastDate.getTime());return str;}//獲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);//加一個年lastDate.set(Calendar.DAY_OF_YEAR, 1);lastDate.roll(Calendar.DAY_OF_YEAR, -1);str=sdf.format(lastDate.getTime());return str;}//獲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);//加一個年lastDate.set(Calendar.DAY_OF_YEAR, 1);str=sdf.format(lastDate.getTime());return str;}//獲得本年有多少天private int getMaxYear(){Calendar cd = Calendar.getInstance();cd.set(Calendar.DAY_OF_YEAR,1);//把日期設為當年第一天cd.roll(Calendar.DAY_OF_YEAR,-1);//把日期回滾一天。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);//獲得當天是一年中的第幾天cd.set(Calendar.DAY_OF_YEAR,1);//把日期設為當年第一天cd.roll(Calendar.DAY_OF_YEAR,-1);//把日期回滾一天。int MaxYear = cd.get(Calendar.DAY_OF_YEAR);if(yearOfNumber == 1){return -MaxYear;}else{return 1-yearOfNumber;}}//獲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;}//獲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";}//獲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";}//獲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;}//獲得本季度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)+"-";//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;}/*** 獲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;}/*** 是否閏年* @param year 年* @return*/public boolean isLeapYear(int year) {return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);}