Java中日期格式轉(zhuǎn)換/** * 字符串轉(zhuǎn)換為java.util.Date<br> * 支持格式為 yyyy.MM.dd G 'at' hh:mm:ss z 如 '2002-1-1 AD at 22:10:59 PSD'<br> * yy/MM/dd HH:mm:ss 如 '2002/1/1 17:55:00'<br> * yy/MM/dd HH:mm:ss pm 如 '2002/1/1 17:55:00 pm'<br> * yy-MM-dd HH:mm:ss 如 '2002-1-1 17:55:00' <br> * yy-MM-dd HH:mm:ss am 如 '2002-1-1 17:55:00 am' <br> * @param time String 字符串<br> * @return Date 日期<br> */public static Date stringToDate(String time){ SimpleDateFormat formatter; int tempPos=time.indexOf("AD") ; time=time.trim() ; formatter = new SimpleDateFormat ("yyyy.MM.dd G 'at' hh:mm:ss z"); if(tempPos>-1){ time=time.substring(0,tempPos)+ "公元"+time.substring(tempPos+"AD".length());//china formatter = new SimpleDateFormat ("yyyy.MM.dd G 'at' hh:mm:ss z"); } tempPos=time.indexOf("-"); if(tempPos>-1&&(time.indexOf(" ")<0)){ formatter = new SimpleDateFormat ("yyyyMMddHHmmssZ"); } else if((time.indexOf("/")>-1) &&(time.indexOf(" ")>-1)){ formatter = new SimpleDateFormat ("yyyy/MM/dd HH:mm:ss"); } else if((time.indexOf("-")>-1) &&(time.indexOf(" ")>-1)){ formatter = new SimpleDateFormat ("yyyy-MM-dd HH:mm:ss"); } else if((time.indexOf("/")>-1) &&(time.indexOf("am")>-1) ||(time.indexOf("pm")>-1)){ formatter = new SimpleDateFormat ("yyyy-MM-dd KK:mm:ss a"); } else if((time.indexOf("-")>-1) &&(time.indexOf("am")>-1) ||(time.indexOf("pm")>-1)){ formatter = new SimpleDateFormat ("yyyy-MM-dd KK:mm:ss a"); } ParsePosition pos = new ParsePosition(0); java.util.Date ctime = formatter.parse(time, pos); return ctime;}/** * 將java.util.Date 格式轉(zhuǎn)換為字符串格式'yyyy-MM-dd HH:mm:ss'(24小時(shí)制)<br> * 如Sat May 11 17:24:21 CST 2002 to '2002-05-11 17:24:21'<br> * @param time Date 日期<br> * @return String 字符串<br> */ public static String dateToString(Date time){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("yyyy-MM-dd HH:mm:ss"); String ctime = formatter.format(time); return ctime;}/** * 將java.util.Date 格式轉(zhuǎn)換為字符串格式'yyyy-MM-dd HH:mm:ss a'(12小時(shí)制)<br> * 如Sat May 11 17:23:22 CST 2002 to '2002-05-11 05:23:22 下午'<br> * @param time Date 日期<br> * @param x int 任意整數(shù)如：1<br> * @return String 字符串<br> */public static String dateToString(Date time,int x){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("yyyy-MM-dd KK:mm:ss a"); String ctime = formatter.format(time); return ctime;}/** *取系統(tǒng)當(dāng)前時(shí)間:返回只值為如下形式 *2002-10-30 20:24:39 * @return String */public static String Now(){ return dateToString(new Date());}/** *取系統(tǒng)當(dāng)前時(shí)間:返回只值為如下形式 *2002-10-30 08:28:56 下午 *@param hour 為任意整數(shù) *@return String */public static String Now(int hour){ return dateToString(new Date(),hour);}/** *取系統(tǒng)當(dāng)前時(shí)間:返回值為如下形式 *2002-10-30 *@return String */public static String getYYYY_MM_DD(){ return dateToString(new Date()).substring(0,10);}/** *取系統(tǒng)給定時(shí)間:返回值為如下形式 *2002-10-30 *@return String */ public static String getYYYY_MM_DD(String date){ return date.substring(0,10);}public static String getHour(){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("H"); String ctime = formatter.format(new Date()); return ctime; }public static String getDay(){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("d"); String ctime = formatter.format(new Date()); return ctime; }public static String getMonth(){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("M"); String ctime = formatter.format(new Date()); return ctime; }public static String getYear(){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("yyyy"); String ctime = formatter.format(new Date()); return ctime; } public static String getWeek(){ SimpleDateFormat formatter; formatter = new SimpleDateFormat ("E"); String ctime = formatter.format(new Date()); return ctime; }在jsp頁(yè)面中的日期格式和sqlserver中的日期格式不一樣，怎樣統(tǒng)一？在頁(yè)面上顯示輸出時(shí)，用下面的函數(shù)處理一下public class DateUtil(){ public static String fmtShortEnu(Date myDate) { SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd"); String strDate = formatter.format(myDate); return strDate;}}new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");new java.text.SimpleDateFormat("yyyy-MM-dd")建議還是把sqlserver的字段類(lèi)型改成varchar的吧，用字符串處理可以完全按照自己的意愿處理，沒(méi)有特殊的需求，不要使用date型字串日期格式轉(zhuǎn)換 用的API是SimpleDateFormat，它是屬於java.text.SimpleDateFormat，所以請(qǐng)記得import進(jìn)來(lái)！用法： SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 這一行最重要，它確立了轉(zhuǎn)換的格式，yyyy是完整的西元年，MM是月份，dd是日期， 至於HH:mm:ss就不需要我再解釋了吧！ ps:為什麼有的格式大寫(xiě)，有的格式小寫(xiě)，那是怕避免混淆，例如MM是月份，mm是分；HH是24小時(shí)制，而hh是12小時(shí)制1.字串轉(zhuǎn)日期： 2002-10-8 15:30:22要把它轉(zhuǎn)成日期，可以用 Date date=sdf.parse("2002-10-8 15:30:22"); 2.日期轉(zhuǎn)字串 假如把今天的日期轉(zhuǎn)成字串可用 String datestr=sdf.format(new Date()); 這個(gè)字串的內(nèi)容便類(lèi)似2002-10-08 14:55:38透過(guò)這個(gè)API我們便可以隨心所欲的將日期轉(zhuǎn)成我們想要的字串格式，例如希望將日期輸出成2002年10月08日， 我們可以這麼寫(xiě)： SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日"); String datestr=sdf.format(new Date()); datestr便會(huì)依照我們?cè)O(shè)定的格式輸出//對(duì)日期格式的轉(zhuǎn)換成（"yyyy-MM-dd"）格式的方法public java.sql.Date Convert(String str){ java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("yyyy-MM-dd"); try { java.util.Date d = sdf.parse(str); java.sql.Date d1 = new java.sql.Date(d.getTime()); return d1; } catch(Exception ex) { ex.printStackTrace(); return null; }}應(yīng)用如下：ctmt.setDate(7,this.Convert(info.getManBirth())); // @DATETIME常用日期問(wèn)題集錦1、獲取服務(wù)器端當(dāng)前日期：<%@ page import="java.util.Date"%><%Date myDate = new Date();%>2、獲取當(dāng)前年、月、日：<%@ page import="java.util.Date"%><%Date myDate = new Date();int thisYear = myDate.getYear() + 1900;//thisYear = 2003int thisMonth = myDate.getMonth() + 1;//thisMonth = 5int thisDate = myDate.getDate();//thisDate = 30%>3、按本地時(shí)區(qū)輸出當(dāng)前日期<%@ page import="java.util.Date"%><%Date myDate = new Date();out.println(myDate.toLocaleString());%>輸出結(jié)果為：2003-5-304、獲取數(shù)據(jù)庫(kù)中字段名為”publish_time“、類(lèi)型為Datetime的值<%@ page import="java.util.Date"%><%...連接數(shù)據(jù)庫(kù)...ResultSet rs = ...Date sDate = rs.getDate("publish_time");%>[code]5、按照指定格式打印日期[code]<%@ page import="java.util.Date"%><%@ page import="java.text.DateFormat"%><%Date dNow = new Date();SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");out.println("It is " + formatter.format(dNow));%>輸出的結(jié)果為：It is 星期五 2003.05.30 at 11:30:46 上午 CST (更為詳盡的格式符號(hào)請(qǐng)參看SimpleDateFormat類(lèi))6、將字符串轉(zhuǎn)換為日期<%@ page import="java.util.Date"%><%@ page import="java.text.DateFormat"%><%String input = "1222-11-11";SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");Date t = null;try{t = formatter.parse(input);out.println(t);}catch(ParseException e){out.println("unparseable using " + formatter);}%>輸出結(jié)果為：Fri Nov 11 00:00:00 CST 12227、計(jì)算日期之間的間隔<%@ page import="java.util.Date"%><%@ page import="java.text.DateFormat"%><%String input = "2003-05-01";SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");Date d1 = null;try{d1 = formatter.parse(input);}catch(ParseException e){out.println("unparseable using " + formatter);}Date d2 = new Date();long diff = d2.getTime() - d1.getTime();out.println("Difference is " + (diff/(1000*60*60*24)) + " days.");%>輸出結(jié)果為：Difference is 29 days.8、日期的加減運(yùn)算方法：用Calendar類(lèi)的add()方法<%@ page import="java.util.*"%><%@ page import="java.text.*"%><%Calendar now = Calendar.getInstance();SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");out.println("It is now " + formatter.format(now.getTime()));now.add(Calendar.DAY_OF_YEAR,-(365*2));out.println("<br>");out.println("Two years ago was " + formatter.format(now.getTime()));%>輸出結(jié)果為：It is now 星期五 2003.05.30 at 01:45:32 下午 CST Two years ago was 星期三 2001.05.30 at 01:45:32 下午 CST9、比較日期方法：用equals()、before()、after()方法<%@ page import="java.util.*"%><%@ page import="java.text.*"%><%DateFormat df = new SimpleDateFormat("yyy-MM-dd");Date d1 = df.parse("2000-01-01");Date d2 = df.parse("1999-12-31");String relation = null;if(d1.equals(d2))relation = "the same date as";else if(d1.before(d2))relation = "before";elserelation = "after";out.println(d1 +" is " + relation + ' ' + d2);%>輸出結(jié)果為：Sat Jan 01 00:00:00 CST 2000 is after Fri Dec 31 00:00:00 CST 199910、記錄一件事所花費(fèi)的時(shí)間方法：調(diào)用兩次System.getTimeMillis()方法，求差值<%@ page import="java.text.*"%><%long t0,t1;t0 = System.currentTimeMillis();out.println("Cyc starts at " + t0);int k = 0;for(int i =0;i<100000;i++){k += i;}t1 = System.currentTimeMillis();out.println("<br>");out.println("Cyc ends at " + t1);out.println("<br>");out.println("This run took " + (t1-t0) + "ms.");%>輸出結(jié)果為：Cyc starts at 1054275312432 Cyc ends at 1054275312442 This run took 10ms.其它：如何格式化小數(shù)<%@ page import="java.text.*"%><%DecimalFormat df = new DecimalFormat(",###.00");double aNumber = 33665448856.6568975;String result = df.format(aNumber);out.println(result);%>輸出結(jié)果為：33,665,448,856.66======================日期比較：在JAVA中日期的計(jì)算與比較可以使用Date和DateFormat來(lái)解決，下面是一段示例代碼：import java.text.*;import java.util.*;public class Test{ public static void main(String[] args){ try{ Date date=new Date(); DateFormat df=DateFormat.getDateTimeInstance(); String now=df.format(date); System.out.println("現(xiàn)在時(shí)間:"+now); System.out.println("現(xiàn)在時(shí)間是否在16:00之前:"+date.before(df.parse("2004-12-24 16:00:00"))); } catch(ParseException e){System.out.print(e.getMessage()); } }}
聯(lián)系客服
