1、获取当前时间,和某个时间进行比较。此时主要拿long型的时间值。
方法如下:
要使用 java.util.Date 。获取当前时间的代码如下
代码如下
Datedate = new Date();
date.getTime();
还有一种方式,使用 System.currentTimeMillis() ;
都是得到一个当前的时间的long型的时间的毫秒值,这个值实际上是当前时间值与1970年一月一号零时零分零秒相差的毫秒数
一、获取当前时间, 格式为: yyyy-mm-dd hh-mm-ss
DateFormat.getDateTimeInstance(2, 2, Locale.CHINESE).format(newjava.util.Date());
二、获取当前时间, 格式为: yyyy年mm月dd日 上午/下午hh时mm分ss秒
代码如下
DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG,Locale.CHINESE).format(newjava.util.Date());
三、获取当前时间(精确到毫秒), 格式为: yyyy-mm-dd hh:mm:ss.nnn
代码如下
newjava.sql.Timestamp(System.currentTimeMillis()).toString();
一. 获取当前系统时间和日期并格式化输出:
代码如下
importjava.util.Date;
import java.text.SimpleDateFormat;
publicclass NowString {
public static void main(String[] args) {
SimpleDateFormat df = newSimpleDateFormat("yyyy-MM-ddHH:mm:ss");//设置日期格式
System.out.println(df.format(new Date()));// newDate()为获取当前系统时间
}
}
二. 在数据库里的日期只以年-月-日的方式输出,可以用下面两种方法:
1、用convert()转化函数:
代码如下
Stringsqlst = "select convert(varchar(10),bookDate,126) asconvertBookDate from roomBook where bookDate between '2007-4-10' and'2007-4-25'";
System.out.println(rs.getString("convertBookDate"));
2、利用SimpleDateFormat类:
先要输入两个java包:
import java.util.Date;
import java.text.SimpleDateFormat;
然后:
定义日期格式:SimpleDateFormat sdf = new SimpleDateFormat(yy-MM-dd);
sql语句为:String sqlStr = "select bookDate from roomBook where bookDatebetween '2007-4-10' and '2007-4-25'";
输出:
System.out.println(df.format(rs.getDate("bookDate")));
java中获取当前日期和时间的方法
代码如下
importjava.util.Date;
importjava.util.Calendar;
importjava.text.SimpleDateFormat;
publicclass TestDate{
public static voidmain(String[] args){
Date now = newDate();
SimpleDateFormat dateFormat= new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");//可以方便地修改日期格式
Stringhehe = dateFormat.format( now );
System.out.println(hehe);
Calendarc = Calendar.getInstance();//可以对每个时间域单独修改
intyear = c.get(Calendar.YEAR);
intmonth = c.get(Calendar.MONTH);
intdate = c.get(Calendar.DATE);
inthour = c.get(Calendar.HOUR_OF_DAY);
int minute =c.get(Calendar.MINUTE);
int second= c.get(Calendar.SECOND);
System.out.println(year + "/" + month +"/" + date + " " +hour + ":" +minute + ":" + second);
}
}
有时候要把String类型的时间转换为Date类型,通过以下的方式,就可以将你刚得到的时间字符串转换为Date类型了。
SimpleDateFormatsdf=new SimpleDateFormat("yyyy-MM-dd");
java.util.Datetime=null;
try {
time= sdf.parse(sdf.format(new Date()));
} catch (ParseException e) {
e.printStackTrace();
}
一个不错日期时间类
代码如下
packagecom.wondersgroup.cc.cti;
importjava.sql.Timestamp;
import java.util.Calendar;
import java.util.Date;
publicclass TestGetSystemTime {
staticDate nowTime = null;
/**
*@param args
*/
public static void main(String[] args) {
//以下为 Clendar 测试代码
int yyyy, mm, dd;
Calendar c =Calendar.getInstance();
yyyy = c.get(Calendar.YEAR);
mm =c.get(Calendar.MONTH) + 1;
dd =c.get(Calendar.DAY_OF_MONTH);
System.out.println("year ="+yyyy);
System.out.println("month = "+mm);
System.out.println("day ="+dd);
// 1. System.currentTimeMillis() 获取系统时间的代码
Timestamp ts =new Timestamp(System.currentTimeMillis());
String dateStr1 =ts.toString();
System.out.println("System.currentTimeMillis() ="+dateStr1);
// 2. date 为获得系统时间的另外一种方法
Date date = newDate();
String dateStr2 = newTimestamp(date.getTime()).toString();
System.out.println(dateStr2);
//得到JAVA运行环境的一些基本属性
System.getProperties().list(System.out);
}
}
一个完整的获取日期实例
格式化日期String-->Date或者 Data-->String
SimpleDateFormat sdf = newSimpleDateFormat("yyyy-MM-dd");
Datedate =sdf.parse("2009-11-04");//String-->Date
Stringsdate= sdf.format(date );//Data-->String===============================================================
packagecom.hefeng.test;
import java.text.DateFormat;
importjava.text.ParsePosition;
import java.text.SimpleDateFormat;
importjava.util.Calendar;
import java.util.Date;
importjava.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 intMaxDate;//一月最大天数
private int MaxYear;//一年最大天数
/**
* @paramargs
*/
public static void main(String[] args) {
TimeTest tt = newTimeTest();
System.out.println("得到6个月后的日期:"+tt.getAfterMonth(6);
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:"+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2008-12-1~2008-
.29:"+TimeTest.getTwoDay("2008-12-1","2008-9-29"));
}
/**
*得到指定月后(前)的日期 参数传负数即可
*/
public static StringgetAfterMonth(int month){
Calendar c = Calendar.getInstance();//获得一个日历的实例
SimpleDateFormat sdf = newSimpleDateFormat("yyyy-MM-dd");
Date date = null;
try{
date =sdf.parse("2009-11-04");//初始日期
}catch(Exception e){
}
c.setTime(date);//设置日历时间
c.add(Calendar.MONTH,month);//在日历的月份上增加6个月
String strDate =sdf.format(c.getTime()));//的到你想要得6个月后的日期
return strDate;
}
/**
*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");
longday = 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 StringgetWeek(String sdate) {
// 再转换为时间
Date date =TimeTest.strToDate(sdate);
Calendar c =Calendar.getInstance();
c.setTime(date);
// inthour=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 newSimpleDateFormat("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 = newSimpleDateFormat("yyyy-MM-dd");
ParsePosition pos = newParsePosition(0);
Date strtodate = formatter.parse(strDate, pos);
returnstrtodate;
}
/**
* 两个时间之间的天数
*
* @param date1
* @paramdate2
* @return
*/
public static long getDays(String date1, Stringdate2) {
if (date1 == null || date1.equals(""))
return 0;
if (date2 ==null || date2.equals(""))
return 0;
// 转换为标准时间
SimpleDateFormatmyFormatter = 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 StringgetDefaultDay(){
String str = "";
SimpleDateFormat sdf=newSimpleDateFormat("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());
returnstr;
}
// 上月第一天
public String getPreviousMonthFirst(){
String str ="";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
CalendarlastDate = 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());
returnstr;
}
//获取当月第一天
public String getFirstDayOfMonth(){
String str ="";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
CalendarlastDate = 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;
intmondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE,mondayPlus+6);
Date monday = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preMonday = df.format(monday);
returnpreMonday;
}
//获取当天时间
public String getNowTime(Stringdateformat){
Date now = new Date();
SimpleDateFormat dateFormat = newSimpleDateFormat(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
privateint 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);
returnpreMonday;
}
//获得相应周的周六的日期
public String getSaturday() {
intmondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 *weeks + 6);
Date monday = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preMonday = df.format(monday);
returnpreMonday;
}
// 获得上周星期日的日期
public String getPreviousWeekSunday(){
weeks=0;
weeks--;
int mondayPlus =this.getMondayPlus();
GregorianCalendar currentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE,mondayPlus+weeks);
Date monday = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preMonday = df.format(monday);
returnpreMonday;
}
// 获得上周星期一的日期
public String getPreviousWeekday(){
weeks--;
int mondayPlus = this.getMondayPlus();
GregorianCalendarcurrentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 *weeks);
Date monday = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preMonday = df.format(monday);
returnpreMonday;
}
// 获得下周星期一的日期
public String getNextMonday(){
weeks++;
int mondayPlus = this.getMondayPlus();
GregorianCalendarcurrentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus +7);
Date monday = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preMonday = df.format(monday);
returnpreMonday;
}
// 获得下周星期日的日期
public String getNextSunday() {
intmondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus +7+6);
Date monday = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preMonday = df.format(monday);
returnpreMonday;
}
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{
return1-monthOfNumber;
}
}
//获得上月最后一天的日期
public StringgetPreviousMonthEnd(){
String str = "";
SimpleDateFormat sdf=newSimpleDateFormat("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());
returnstr;
}
//获得下个月第一天的日期
public String getNextMonthFirst(){
String str ="";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
CalendarlastDate =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());
returnstr;
}
//获得下个月最后一天的日期
public String getNextMonthEnd(){
String str ="";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
CalendarlastDate =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());
returnstr;
}
//获得明年最后一天的日期
public String getNextYearEnd(){
String str ="";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
CalendarlastDate =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());
returnstr;
}
//获得明年第一天的日期
public String getNextYearFirst(){
String str ="";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
CalendarlastDate =Calendar.getInstance();
lastDate.add(Calendar.YEAR,1);//加一个年
lastDate.set(Calendar.DAY_OF_YEAR,1);
str=sdf.format(lastDate.getTime());
returnstr;
}
//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。
intMaxYear = cd.get(Calendar.DAY_OF_YEAR);
return MaxYear;
}
private intgetYearPlus(){
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。
intMaxYear = cd.get(Calendar.DAY_OF_YEAR);
if(yearOfNumber == 1){
return-MaxYear;
}else{
return1-yearOfNumber;
}
}
//获得本年第一天的日期
public StringgetCurrentYearFirst(){
int yearPlus =this.getYearPlus();
GregorianCalendar currentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE,yearPlus);
DateyearDay = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preYearDay =df.format(yearDay);
return preYearDay;
}
//获得本年最后一天的日期 *
publicString getCurrentYearEnd(){
Date date = new Date();
SimpleDateFormatdateFormat = 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 = newDate();
SimpleDateFormat dateFormat = newSimpleDateFormat("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--;
returnyears_value+"-1-1";
}
//获得上年最后一天的日期
public StringgetPreviousYearEnd(){
weeks--;
int yearPlus =this.getYearPlus();
GregorianCalendar currentDate = newGregorianCalendar();
currentDate.add(GregorianCalendar.DATE,yearPlus+MaxYear*weeks+(MaxYear-1));
DateyearDay = currentDate.getTime();
DateFormat df =DateFormat.getDateInstance();
String preYearDay =df.format(yearDay);
getThisSeasonTime(11);
returnpreYearDay;
}
//获得本季度
public String getThisSeasonTime(intmonth){
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;
}
intstart_month = array[season-1][0];
int end_month = array[season-1][2];
Datedate = new Date();
SimpleDateFormat dateFormat = newSimpleDateFormat("yyyy");//可以方
便地修
改日期格式
String years =dateFormat.format(date);
int years_value = Integer.parseInt(years);
intstart_days=1;//years+"-"+String.valueOf(start_month)+"-
";//getLastDayOfMonth(years_value,start_month);
intend_days = getLastDayOfMonth(years_value,end_month);
String seasonDate=
years_value+"-"+start_month+"-"+start_days+";"+years_value+"-"+end_month+"-"+end_days;
returnseasonDate;
}
/**
* 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 {
return28;
}
}
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);
}