java计算时间,java计算时间间隔

本文目录一览：

1、java类里面怎么计算时间？
2、JAVA 时间计算
3、java整么计算时间
4、java 时间计算
5、计算Java程序执行时间的几种方法
6、java计算时间

java类里面怎么计算时间？

用Calendar类里面的add(int field, int amount) 方法进行时间的计算。示例代码如下:

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

public class TestCalendar {

public static void main(String[] args){

Calendar c = Calendar.getInstance();

SimpleDateFormat format = new SimpleDateFormat(“yyyy-MM-dd HH:mm:ss”);

try {

c.setTime(format.parse(“2011-08-05 14:49:45”));

System.out.println(“原来的时间:”+format.format(c.getTime()));

c.add(Calendar.MINUTE,20);

System.out.println(“计算后得到的时间:”+format.format(c.getTime()));

} catch (ParseException e) {

e.printStackTrace();

}

JAVA 时间计算

如果今天是2011年1月5日，先引入import java.util.Date;import java.text.SimpleDateFormat;

Date time=new Date();

Calendar cal=Calendar.getInstance();

cal.setTime(time);//日历为今天

long tm,tm1;

tm=cal.getTimeInMillis();//得到当前时间与1970年1月1日0点相距的毫秒数

tm1=tm-(24*60*60*1000);//得到昨天与1970年1月1日0点相距的毫秒数

Date time1=new Date(tm1);

SimpleDateFormat sdf=new SimpleDateFormat(“yyyy-MM-dd”);

String tm=sdf.format(time1);//tm就是昨天的日期的字符串表示

java整么计算时间

提供一个时间操作类给你，你可以调用里面的dateDiff方法，dateDiff（new Date(), getDateFromString(“明天的字符串”）表示的就是现在到明天0点之前的差距天数。

你要分钟数的话就自己改一下dateDiff，不要除以60和24就是分钟了

以下是工具类代码

import org.apache.log4j.Logger;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;

public class AdDateUtil {

private static Logger logger = Logger.getLogger(AdDateUtil.class);

static public String getNowStr(String format) {

SimpleDateFormat sdf = new SimpleDateFormat(format);

String now = sdf.format(new Date());

return now;

}

static public Date getFormatDate(String date, String format) {

SimpleDateFormat sdf = new SimpleDateFormat(format);

Date d = new Date();

try {

d = sdf.parse(date);

} catch (ParseException e) {

logger.error(e);

}

return d;

}

static public String getDateStr(Date date, String format) {

SimpleDateFormat sdf = new SimpleDateFormat(format);

String d = sdf.format(date);

return d;

}

static public String getPadZeroString(String s, int size) {

StringBuffer sb = new StringBuffer();

for (int i = 0; i (size – s.length()); i++) {

sb.append(“0”);

}

sb.append(s);

return sb.toString();

}

/**

* 得到某月的天数

* @param year

* @param month

* @return

static public int getDayCountOfMonth(String year, String month) {

Calendar cal = Calendar.getInstance();

// 年

cal.set(Calendar.YEAR, Integer.parseInt(year));

// 月，因为Calendar里的月是从0开始，所以要-1

cal.set(Calendar.MONTH, Integer.parseInt(month) – 1);

return cal.getActualMaximum(Calendar.DAY_OF_MONTH);

}

static public String getYesterday(String format) {

SimpleDateFormat df = new SimpleDateFormat(format);

Calendar now = Calendar.getInstance();

now.roll(Calendar.DAY_OF_YEAR, -1); //昨天

return df.format(now.getTime());

}

/**

* 获取和今天附近的某天

* @param format

* @param diff

* @return

static public String getADay(String format, int diff) {

SimpleDateFormat df = new SimpleDateFormat(format);

Calendar now = Calendar.getInstance();

int beforeM = now.get(Calendar.MONTH);

now.roll(Calendar.DAY_OF_YEAR, diff); //

int nowM = now.get(Calendar.MONTH);

//必须进行日期处理，否则2009-01-04日前七天是2009-12-28

if (nowM beforeM) {

now.roll(Calendar.YEAR, -1);

}

return df.format(now.getTime());

}

static public String getTomorrow(String format) {

SimpleDateFormat df = new SimpleDateFormat(format);

Calendar now = Calendar.getInstance();

now.roll(Calendar.DAY_OF_YEAR, 1); //明天

return df.format(now.getTime());

}

/**

* 得到最近num天的全部日期

* 说明:

* 1.日期是从昨天开始算的.

* 2.如果num=2 , 日期是2008-03-14 ,则返回的结果为 2008-03-12、2008-03-13

* @param num

* @return

public static String[] getDaysByNum(int num, String date) {

SimpleDateFormat sdf = new SimpleDateFormat(“yyyy-MM-dd”);

String[] result = { };

Calendar cal = Calendar.getInstance();

cal.setTime(getDateFromString(date, “yyyy-MM-dd”));

//最近一周

result = new String[num];

for (int i = num; i 0; i–) {

cal.add(Calendar.DAY_OF_YEAR, -1);

result[i – 1] = sdf.format(new Date(cal.getTimeInMillis()));

}

return result;

}

public static Date getDateFromString(String dateStr, String format) {

if ((dateStr == null) || (format == null)) {

try {

throw new Exception(“数据类型异常” + dateStr + “|” + format);

} catch (Exception e) {

logger.error(“数据类型异常:” + e);

}

SimpleDateFormat df = new SimpleDateFormat(format);

Date date;

try {

date = df.parse(dateStr);

return date;

} catch (Exception ex) {

logger.error(ex);

return new Date();

}

static public int getNowYear() {

Calendar cal = Calendar.getInstance();

return cal.get(Calendar.YEAR);

}

static public int getNowMonth() {

Calendar cal = Calendar.getInstance();

return cal.get(Calendar.MONTH) + 1;

}

public static String[] getMonthRang(String year, String month) {

String beginDate = year + “-” + month + “-01”;

String endDate = year + “-” + month + “-” +

getDayCountOfMonth(year, month);

return getDaysByRang(beginDate, endDate);

}

public static String[] getDaysByRang(String beginDate, String endDate) {

SimpleDateFormat sdf = new SimpleDateFormat(“yyyy-MM-dd”);

//得到两个日期间相差多少天

int num = dateDiff(beginDate, endDate);

if (num 0) {

//颠倒一下日期

String tmp = beginDate;

beginDate = endDate;

endDate = tmp;

num = 0 – num;

}

String[] result = { };

Calendar cal = Calendar.getInstance();

try {

cal.setTime(sdf.parse(beginDate));

} catch (ParseException e) {

e.printStackTrace();

}

num = num + 1; //把开始和结束日期都包含进去

result = new String[num];

for (int i = 0; i num; i++) {

if (i 0) {

cal.add(Calendar.DAY_OF_YEAR, 1);

}

result[i] = sdf.format(new Date(cal.getTimeInMillis()));

}

return result;

}

public static int dateDiff(String beginDate, String endDate) {

SimpleDateFormat sdf = new SimpleDateFormat(“yyyy-MM-dd”);

Date date = null;

try {

date = sdf.parse(endDate);

} catch (ParseException e) {

date = new Date();

e.printStackTrace();

}

long end = date.getTime();

try {

date = sdf.parse(beginDate);

} catch (ParseException e) {

date = new Date();

e.printStackTrace();

}

long begin = date.getTime();

long day = (end – begin) / (1000 * 3600 * 24); //除1000是把毫秒变成秒

return Integer.parseInt(Long.toString(day));

}

public static void main(String[] args) {

System.out.println(AdDateUtil.getADay(“yyyy-MM-dd”, -7));

}

java 时间计算

自己写的一个，使用了两种方法实现了你的需求，希望可以帮到你

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;

public class TimeTest {

/**

* @param args

public static void main(String[] args) {

TimeTest t = new TimeTest();

SimpleDateFormat formater = new SimpleDateFormat(“yyyy/MM/dd HH:mm:ss”);

String currentTime = formater.format(new Date());

System.out.println(“当前日期：”+currentTime);

System.out.println(“昨日日期：”+t.getYtime(currentTime));

System.out.println(“上月日期：”+t.getLtime(currentTime));

}

// 昨天

public String getYtime(String today){

String ytime = “”;

Date date = new Date(today);

date = new Date(date.getTime() – 1000 * 60 * 60 * 24);

ytime = new SimpleDateFormat(“yyyy/MM/dd HH:mm:ss”).format(date);

return ytime;

}

// 上月

public String getLtime(String today){

String ltime = “”;

Date date = new Date(today);

Calendar cal= Calendar.getInstance();

cal.setTime(date);

cal.add(Calendar.DATE, -1);

cal.add(Calendar.MONTH, -1);

date = cal.getTime();

ltime = new SimpleDateFormat(“yyyy/MM/dd HH:mm:ss”).format(date);

return ltime;

}

计算Java程序执行时间的几种方法

最简单的就是直接获取开始时间、结束时间，计算时间差

public class Demo {

public static void main(String[] args) {

long startTime = System.currentTimeMillis(); //获取开始时间

doSomething(); //测试的代码段

long endTime = System.currentTimeMillis(); //获取结束时间

System.out.println(“程序运行时间：” + (endTime – startTime) + “ms”); //输出程序运行时间

}