java時間日期使用與查詢代碼詳解

只要格式正確，直接比較字符串就可以了呀，精確到秒的也一樣

String s1 = "2003-12-12 11:30:24"; String s2 = "2004-04-01 13:31:40"; int res = s1.compareTo(s2);

求日期差

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date begin=df.parse("2004-01-02 11:30:24"); Date end = df.parse("2004-03-26 13:31:40"); long between=(end.getTime()-begin.getTime())/1000;//除以1000是為了轉換成秒int day=between/(24*3600); int hour=between%(24*3600)/3600; int minute=between%3600/60; int second=between%60;

經常用到時間日期類，所以就將常用的日期方法和屬性都歸納總結如下，方便大家查找

1.計算某一月份的最大天數

Calendar time=Calendar.getInstance(); time.clear(); time.set(Calendar.YEAR,year); time.set(Calendar.MONTH,i-1);//注意,Calendar對象默認一月為0 int day=time.getActualMaximum(Calendar.DAY_OF_MONTH);//本月份的天數

注：在使用set方法之前，最好先clear一下，否則很多信息會繼承自系統當前時間

2.Calendar和Date的轉化

(1) Calendar轉化為Date

 Calendar cal=Calendar.getInstance(); Date date=cal.getTime();

(2) Date轉化為Calendar

 Date date=new Date(); Calendar cal=Calendar.getInstance(); cal.setTime(date);

3.格式化輸出日期時間

Date date=new Date(); SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); System.out.println(df.format(date));

4.計算一年中的第幾星期

(1)計算某一天是一年中的第幾星期

Calendar cal=Calendar.getInstance(); cal.set(Calendar.YEAR, 2006); cal.set(Calendar.MONTH, 9); cal.set(Calendar.DAY_OF_MONTH, 3); int weekno=cal.get(Calendar.WEEK_OF_YEAR);

(2)計算一年中的第幾星期是幾號

SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd"); Calendar cal=Calendar.getInstance(); cal.set(Calendar.YEAR, 2006); cal.set(Calendar.WEEK_OF_YEAR, 1); cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY); System.out.println(df.format(cal.getTime()));

輸出:

 2006-01-02

5.add()和roll()的用法
(1)add()方法

SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd"); Calendar cal=Calendar.getInstance(); cal.set(Calendar.YEAR, 2006); cal.set(Calendar.MONTH, 9); cal.set(Calendar.DAY_OF_MONTH, 3); cal.add(Calendar.DATE, -4); Date date=cal.getTime(); System.out.println(df.format(date)); cal.add(Calendar.DATE, 4); date=cal.getTime(); System.out.println(df.format(date));

輸出：
2006-08-30
2006-10-03

(2)roll方法

cal.set(Calendar.YEAR, 2006); cal.set(Calendar.MONTH, 9); cal.set(Calendar.DAY_OF_MONTH, 3); cal.roll(Calendar.DATE, -4); date=cal.getTime(); System.out.println(df.format(date)); cal.roll(Calendar.DATE, 4); date=cal.getTime(); System.out.println(df.format(date));

輸出：

2006-10-29

2006-10-03

可見，roll()方法在本月內循環，一般使用add()方法；

6.計算兩個任意時間中間的間隔天數

(1)傳進Calendar對象

/** *//**計算兩個時間之間相隔天數* @param startday 開始時間* @param endday 結束時間* @return */public int getIntervalDays(Calendar startday,Calendar endday)...{//確保startday在endday之前if(startday.after(endday))...{Calendar cal=startday;startday=endday;endday=cal;}//分別得到兩個時間的毫秒數long sl=startday.getTimeInMillis();long el=endday.getTimeInMillis();long ei=el-sl;//根據毫秒數計算間隔天數return (int)(ei/(1000*60*60*24));}

(2)傳進Date對象

/** *//**計算兩個時間之間相隔天數* @param startday 開始時間* @param endday 結束時間* @return */public int getIntervalDays(Date startday,Date endday)...{//確保startday在endday之前if(startday.after(endday))...{Date cal=startday;startday=endday;endday=cal;}//分別得到兩個時間的毫秒數long sl=startday.getTime();long el=endday.getTime();long ei=el-sl;//根據毫秒數計算間隔天數return (int)(ei/(1000*60*60*24));}

同理，可以用相同的方法計算出任意兩個時間相隔的小時數，分鐘數，秒鐘數等注：以上方法是完全按時間計算，有時並不能令人滿意，如：

 startday="2006-10-11 20:00:00" endday="2006-10-12 8:00:00"

計算結果為0，但是我們也許相讓計算結果變為1，此時可以用如下方法實現：
在傳參之前，先設定endday的時間，如：

 endday.set(Calendar.HOUR_OF_DAY, 23); endday.set(Calendar.MINUTE, 59); endday.set(Calendar.SECOND, 59); endday.set(Calendar.MILLISECOND, 59);

這樣再傳進去startday,endday，則結果就如我們所願了。不過，如果嫌以上方法麻煩，可以參考以下方法：
(3)改進精確計算相隔天數的方法

public int getDaysBetween (Calendar d1, Calendar d2) ...{if (d1.after(d2)) ...{// swap dates so that d1 is start and d2 is end java.util.Calendar swap = d1;d1 = d2;d2 = swap;}int days = d2.get(Calendar.DAY_OF_YEAR) - d1.get(Calendar.DAY_OF_YEAR);int y2 = d2.get(Calendar.YEAR);if (d1.get(Calendar.YEAR) != y2) ...{d1 = (Calendar) d1.clone();do ...{days += d1.getActualMaximum(Calendar.DAY_OF_YEAR);//得到當年的實際天數d1.add(Calendar.YEAR, 1);}while (d1.get(Calendar.YEAR) != y2);}return days;}

獲取系統當前時間：

 public static String getSystemTime(){Date date=new Date();SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");return df.format(date);}//字符串轉化成時間類型（字符串可以是任意類型，只要和SimpleDateFormat中的格式一致即可） java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("M/dd/yyyy hh:mm:ss a",java.util.Locale.US);java.util.Date d = sdf.parse("5/13/2003 10:31:37 AM");SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");String mDateTime1=formatter.format(d);//當前時間Calendar cal = Calendar.getInstance();// SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss GEDF w W a EF");String mDateTime=formatter.format(cal.getTime());//1年前日期java.util.Date myDate=new java.util.Date();long myTime=(myDate.getTime()/1000)-60*60*24*365;myDate.setTime(myTime*1000);String mDate=formatter.format(myDate);//明天日期myDate=new java.util.Date();myTime=(myDate.getTime()/1000)+60*60*24;myDate.setTime(myTime*1000);mDate=formatter.format(myDate);//兩個時間之間的天數SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");java.util.Date date= myFormatter.parse("2003-05-1");java.util.Date mydate= myFormatter.parse("1899-12-30");long day=(date.getTime()-mydate.getTime())/(24*60*60*1000);//加半小時SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");java.util.Date date1 = format.parse("2002-02-28 23:16:00");long Time=(date1.getTime()/1000)+60*30;date1.setTime(Time*1000);String mydate1=formatter.format(date1);//年月週求日期SimpleDateFormat formatter2 = new SimpleDateFormat("yyyy-MM FE");java.util.Date date2= formatter2.parse("2003-05 5 星期五");SimpleDateFormat formatter3 = new SimpleDateFormat("yyyy-MM-dd");String mydate2=formatter3.format(date2);//求是星期幾mydate= myFormatter.parse("2001-1-1");SimpleDateFormat formatter4 = new SimpleDateFormat("E");String mydate3=formatter4.format(mydate);

在開發web應用中，針對不同的數據庫日期類型，我們需要在我們的程序中對日期類型做各種不同的轉換。若對應數據庫數據是oracle的Date類型，即只需要年月日的，可以選擇使用java.sql.Date類型，若對應的是MSsqlserver數據庫的DateTime類型，即需要年月日時分秒的，選擇java.sql.Timestamp類型

你可以使用dateFormat定義時間日期的格式，轉一個字符串即可

package personal.jessica;import java.util.Date;import java.util.Calendar;import java.sql.Timestamp;import java.text.DateFormat;import java.text.SimpleDateFormat;import java.util.Locale;class Datetest{/** *method 將字符串類型的日期轉換為一個timestamp（時間戳記java.sql.Timestamp） *@param dateString 需要轉換為timestamp的字符串*@return dataTime timestamp */public final static java.sql.Timestamp string2Time(String dateString) throws java.text.ParseException {DateFormat dateFormat;dateFormat = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss.SSS", Locale.ENGLISH);//設定格式//dateFormat = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss", Locale.ENGLISH); dateFormat.setLenient(false);java.util.Date timeDate = dateFormat.parse(dateString);//util類型java.sql.Timestamp dateTime = new java.sql.Timestamp(timeDate.getTime());//Timestamp類型,timeDate.getTime()返回一個long型return dateTime;}/** *method 將字符串類型的日期轉換為一個Date（java.sql.Date） *@param dateString 需要轉換為Date的字符串*@return dataTime Date */public final static java.sql.Date string2Date(String dateString) throws java.lang.Exception {DateFormat dateFormat;dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.ENGLISH);dateFormat.setLenient(false);java.util.Date timeDate = dateFormat.parse(dateString);//util類型java.sql.Date dateTime = new java.sql.Date(timeDate.getTime());//sql類型return dateTime;}public static void main(String[] args){Date da = new Date();//注意：這個地方da.getTime()得到的是一個long型的值System.out.println(da.getTime());//由日期date轉換為timestamp //第一種方法：使用new Timestamp(long) Timestamp t = new Timestamp(new Date().getTime());System.out.println(t);//第二種方法：使用Timestamp(int year,int month,int date,int hour,int minute,int second,int nano) Timestamp tt = new Timestamp(Calendar.getInstance().get( Calendar.YEAR) - 1900, Calendar.getInstance().get( Calendar.MONTH), Calendar.getInstance().get( Calendar.DATE), Calendar.getInstance().get( Calendar.HOUR), Calendar.getInstance().get( Calendar.MINUTE), Calendar.getInstance().get( Calendar.SECOND), 0);System.out.println(tt);try {String sToDate = "2005-8-18";//用於轉換成java.sql.Date的字符串String sToTimestamp = "2005-8-18 14:21:12.123";//用於轉換成java.sql.Timestamp的字符串Date date1 = string2Date(sToDate);Timestamp date2 = string2Time(sToTimestamp);System.out.println("Date:"+date1.toString());//結果顯示System.out.println("Timestamp:"+date2.toString());//結果顯示}catch(Exception e) {e.printStackTrace();}}}

下面是例子：

Java代碼

package test;import java.text.DateFormat;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.Hashtable;import javax.swing.JOptionPane;public class Test2{public static Boolean isdate(String s){String a[]=s.split("-");Boolean flg=true;if(!(Integer.parseint(a[0])>=1950 && Integer.parseint(a[0])<=2050)){flg=false;}return flg;}public static Boolean checkDate(String s){Boolean ret = true;try{DateFormat df = new SimpleDateFormat("yyyy-MM-dd");ret = df.format(df.parse(s)).equals(s);}catch(ParseException e){ret = false;}return ret;}public Object dateinfo(String s){String a[]=s.split("-",2);Hashtable fest =new Hashtable();fest.put("01-01","元旦節");fest.put("02-14","情人節");fest.put("03-12","植樹節");fest.put("03-15","消費者節");fest.put("04-01","愚人節");fest.put("04-05","清明節");fest.put("05-01","勞動節");fest.put("06-01","兒童節");fest.put("07-01","建黨節");fest.put("08-01","建軍節");fest.put("09-10","教師節");fest.put("10-01","國慶節");fest.put("12-25","聖誕節");if(fest.containsKey(a[1])){return fest.get(a[1]);} else{return "無節日";}}public String xingzuo(Date s){Calendar cal = Calendar.getInstance();cal.setTime(s);String xingzuo="無";int day=cal.get(Calendar.DAY_OF_YEAR);if((cal.get(Calendar.YEAR)%4==0)&&(cal.get(Calendar.YEAR)%100!=0)||(cal.get(Calendar.YEAR)%400==0)){if((day>=1 &&day<=19)||(day>=357&&day<=366)){xingzuo= "魔蠍座";} else if(day>=20 &&day<=49){xingzuo= "水瓶座";} else if(day>=50 &&day<=80){xingzuo= "雙魚座";} else if(day>=81 &&day<=110){xingzuo= "白羊座";} else if(day>=111 &&day<=141){xingzuo= "金牛座";} else if(day>=142 &&day<=173){xingzuo= "雙子座";} else if(day>=174 &&day<=203){xingzuo= "巨蟹座";} else if(day>=204 &&day<=235){xingzuo= "獅子座";} else if(day>=236 &&day<=266){xingzuo= "處女座";} else if(day>=267 &&day<=296){xingzuo= "天秤座";} else if(day>=297 &&day<=326){xingzuo= "天蠍座";} else if(day>=327 &&day<=356){xingzuo= "射手座";}} else{if((day>=1 &&day<=19)||(day>=357&&day<=366)){xingzuo= "魔蠍座";} else if(day>=20 &&day<=48){xingzuo= "水瓶座";} else if(day>=49 &&day<=79){xingzuo= "雙魚座";} else if(day>=80 &&day<=109){xingzuo= "白羊座";} else if(day>=110 &&day<=140){xingzuo= "金牛座";} else if(day>=141 &&day<=172){xingzuo= "雙子座";} else if(day>=173 &&day<=202){xingzuo= "巨蟹座";} else if(day>=203 &&day<=234){xingzuo= "獅子座";} else if(day>=235 &&day<=265){xingzuo= "處女座";} else if(day>=266 &&day<=295){xingzuo= "天秤座";} else if(day>=296 &&day<=325){xingzuo= "天蠍座";} else if(day>=326 &&day<=355){xingzuo= "射手座";}}return xingzuo;}public Date parseDate(String s){Si​​mpleDateFormat bartDateFormat = new SimpleDateFormat("yyyy-MM-dd");try {Date date3 = bartDateFormat.parse(s);date3=bartDateFormat.parse(s);return date3;}catch (Exception ex) {return null;}}public static void main(String[] args) {Calendar cal = Calendar.getInstance();Test2 test2=new Test2();String date1=JOptionPane.showInputDialog("請你輸入日期，格式如2000-10-15");while(!(Test2.checkDate(date1)&&Test2.isdate(date1))){date1=JOptionPane.showInputDialog("請你輸入日期，格式如2000-10-15");}SimpleDateFormat bartDateFormat1 = new SimpleDateFormat("yyyy,MM,dd,EEEE");SimpleDateFormat bartDateFormat2 = new SimpleDateFormat("yyyy-MM-dd");Date date2=test2.parseDate(date1);String festinfo=(String)test2.dateinfo(date1);System.out.println(bartDateFormat1.format(date2) +","+ festinfo+","+ test2.xingzuo(date2));String day=JOptionPane.showInputDialog("請你輸入要查詢N天后的日期信息");cal.setTime(date2);cal.add(Calendar.DATE, Integer.parseint(day));String date5=bartDateFormat2.format(cal.getTime());festinfo=(String)test2.dateinfo(date5);System.out.println(bartDateFormat1.format(cal.getTime())+","+ festinfo+","+ test2.xingzuo(cal.getTime()));}}

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