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java时间日期使用与查询代码详解

时间:2022-06-29 01:01:58 编辑:袖梨 来源:一聚教程网

只要格式正确,直接比较字符串就可以了呀,精确到秒的也一样

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是为了转换成秒  
 int  day=between/(24*3600);  
 int  hour=between%(24*3600)/3600;  
 int  minute=between%3600/60;  
 int  second=between%60; 

经常用到时间日期类,所以就将常用的日期方法和属性都归纳总结如下,方便大家查找

1.计算某一月份的最大天数

Calendar time=Calendar.getInstance(); 
time.clear(); 
time.set(Calendar.YEAR,year); 
time.set(Calendar.MONTH,i-1);//注意,Calendar对象默认一月为0 
int day=time.getActualMaximum(Calendar.DAY_OF_MONTH);//本月份的天数 

注:在使用set方法之前,最好先clear一下,否则很多信息会继承自系统当前时间

2.Calendar和Date的转化

(1) Calendar转化为Date

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

(2) Date转化为Calendar

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

3.格式化输出日期时间

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

4.计算一年中的第几星期

(1)计算某一天是一年中的第几星期

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)计算一年中的第几星期是几号

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())); 

输出:

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)); 

输出:
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)); 

输出:

2006-10-29

2006-10-03

可见,roll()方法在本月内循环,一般使用add()方法;

6.计算两个任意时间中间的间隔天数

(1)传进Calendar对象

/** */
/**计算两个时间之间相隔天数 
* @param startday 开始时间 
* @param endday 结束时间 
* @return 
*/
public int getIntervalDays(Calendar startday,Calendar endday)...{
	//确保startday在endday之前 
	if(startday.after(endday))...{
		Calendar cal=startday;
		startday=endday;
		endday=cal;
	}
	//分别得到两个时间的毫秒数 
	long sl=startday.getTimeInMillis();
	long el=endday.getTimeInMillis();
	long ei=el-sl;
	//根据毫秒数计算间隔天数 
	return (int)(ei/(1000*60*60*24));
}

(2)传进Date对象

/** */
/**计算两个时间之间相隔天数 
* @param startday 开始时间 
* @param endday 结束时间 
* @return 
*/
public int getIntervalDays(Date startday,Date endday)...{
	//确保startday在endday之前 
	if(startday.after(endday))...{
		Date cal=startday;
		startday=endday;
		endday=cal;
	}
	//分别得到两个时间的毫秒数 
	long sl=startday.getTime();
	long el=endday.getTime();
	long ei=el-sl;
	//根据毫秒数计算间隔天数 
	return (int)(ei/(1000*60*60*24));
}

同理,可以用相同的方法计算出任意两个时间相隔的小时数,分钟数,秒钟数等
注:以上方法是完全按时间计算,有时并不能令人满意,如:

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

计算结果为0,但是我们也许相让计算结果变为1,此时可以用如下方法实现:
在传参之前,先设定endday的时间,如:

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

这样再传进去startday,endday,则结果就如我们所愿了。不过,如果嫌以上方法麻烦,可以参考以下方法:
(3)改进精确计算相隔天数的方法

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);
			//得到当年的实际天数 
			d1.add(Calendar.YEAR, 1);
		}
		while (d1.get(Calendar.YEAR) != y2);
	}
	return days;
}

获取系统当前时间:

public static String getSystemTime(){
	Date date=new Date();
	SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	return df.format(date);
}
//字符串转化成时间类型(字符串可以是任意类型,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);
//当前时间 
Calendar cal = Calendar.getInstance();
// SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss G E D F w W a E F");
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);
//两个时间之间的天数 
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);
//加半小时 
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);
//年月周求日期 
SimpleDateFormat formatter2 = new SimpleDateFormat("yyyy-MM F E");
java.util.Date date2= formatter2.parse("2003-05 5 星期五");
SimpleDateFormat formatter3 = new SimpleDateFormat("yyyy-MM-dd");
String mydate2=formatter3.format(date2);
//求是星期几 
mydate= myFormatter.parse("2001-1-1");
SimpleDateFormat formatter4 = new SimpleDateFormat("E");
String mydate3=formatter4.format(mydate);

在开发web应用中,针对不同的数据库日期类型,我们需要在我们的程序中对日期类型做各种不同的转换。若对应数据库数据是oracle的Date类型,即只需要年月日的,可以选择使用java.sql.Date类型,若对应的是MSsqlserver数据库的DateTime类型,即需要年月日时分秒的,选择java.sql.Timestamp类型

你可以使用dateFormat定义时间日期的格式,转一个字符串即可

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 将字符串类型的日期转换为一个timestamp(时间戳记java.sql.Timestamp) 
*@param dateString 需要转换为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);
		//设定格式  
		//dateFormat = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss", Locale.ENGLISH);  
		dateFormat.setLenient(false);
		java.util.Date timeDate = dateFormat.parse(dateString);
		//util类型  
		java.sql.Timestamp dateTime = new java.sql.Timestamp(timeDate.getTime());
		//Timestamp类型,timeDate.getTime()返回一个long型  
		return dateTime;
	}
	/** 
*method 将字符串类型的日期转换为一个Date(java.sql.Date) 
*@param dateString 需要转换为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类型  
		java.sql.Date dateTime = new java.sql.Date(timeDate.getTime());
		//sql类型  
		return dateTime;
	}
	public static void main(String[] args){
		Date da = new Date();
		//注意:这个地方da.getTime()得到的是一个long型的值  
		System.out.println(da.getTime());
		//由日期date转换为timestamp  
		//第一种方法:使用new Timestamp(long)  
		Timestamp t = new Timestamp(new Date().getTime());
		System.out.println(t);
		//第二种方法: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";
			//用于转换成java.sql.Date的字符串  
			String sToTimestamp = "2005-8-18 14:21:12.123";
			//用于转换成java.sql.Timestamp的字符串  
			Date date1 = string2Date(sToDate);
			Timestamp date2 = string2Time(sToTimestamp);
			System.out.println("Date:"+date1.toString());
			//结果显示  
			System.out.println("Timestamp:"+date2.toString());
			//结果显示
		}
		catch(Exception e) {
			e.printStackTrace();
		}
	}
}

下面是例子:

Java代码

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","元旦节");
		fest.put("02-14","情人节");
		fest.put("03-12","植树节");
		fest.put("03-15","消费者节");
		fest.put("04-01","愚人节");
		fest.put("04-05","清明节");
		fest.put("05-01","劳动节");
		fest.put("06-01","儿童节");
		fest.put("07-01","建党节");
		fest.put("08-01","建军节");
		fest.put("09-10","教师节");
		fest.put("10-01","国庆节");
		fest.put("12-25","圣诞节");
		if(fest.containsKey(a[1])){
			return fest.get(a[1]);
		} else{
			return "无节日";
		}
	}
	public String xingzuo(Date s){
		Calendar cal = Calendar.getInstance();
		cal.setTime(s);
		String xingzuo="无";
		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= "魔蝎座";
			} else if(day>=20 &&day<=49){
				xingzuo= "水瓶座";
			} else if(day>=50 &&day<=80){
				xingzuo= "双鱼座";
			} 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= "双子座";
			} else if(day>=174 &&day<=203){
				xingzuo= "巨蟹座";
			} else if(day>=204 &&day<=235){
				xingzuo= "狮子座";
			} else if(day>=236 &&day<=266){
				xingzuo= "处女座";
			} else if(day>=267 &&day<=296){
				xingzuo= "天秤座";
			} else if(day>=297 &&day<=326){
				xingzuo= "天蝎座";
			} else if(day>=327 &&day<=356){
				xingzuo= "射手座";
			}
		} else{
			if((day>=1 &&day<=19)||(day>=357&&day<=366)){
				xingzuo= "魔蝎座";
			} else if(day>=20 &&day<=48){
				xingzuo= "水瓶座";
			} else if(day>=49 &&day<=79){
				xingzuo= "双鱼座";
			} 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= "双子座";
			} else if(day>=173 &&day<=202){
				xingzuo= "巨蟹座";
			} else if(day>=203 &&day<=234){
				xingzuo= "狮子座";
			} else if(day>=235 &&day<=265){
				xingzuo= "处女座";
			} else if(day>=266 &&day<=295){
				xingzuo= "天秤座";
			} else if(day>=296 &&day<=325){
				xingzuo= "天蝎座";
			} else if(day>=326 &&day<=355){
				xingzuo= "射手座";
			}
		}
		return xingzuo;
	}
	public Date parseDate(String s){
		SimpleDateFormat 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("请你输入日期,格式如2000-10-15");
		while(!(Test2.checkDate(date1)&&Test2.isdate(date1))){
			date1=JOptionPane.showInputDialog("请你输入日期,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("请你输入要查询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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