Java adds and subtracts the date Date class the year the month the time difference and so on
- 2020-05-26 08:36:39
- OfStack
Implementation code 1:
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class DateTestUtil {
public static void main(String[] args) throws Exception {
SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
String str="20110823";
Date dt=sdf.parse(str);
Calendar rightNow = Calendar.getInstance();
rightNow.setTime(dt);
rightNow.add(Calendar.YEAR,-1);// Date minus 1 years
rightNow.add(Calendar.MONTH,3);// The date and 3 months
rightNow.add(Calendar.DAY_OF_YEAR,10);// The date and 10 day
Date dt1=rightNow.getTime();
String reStr = sdf.format(dt1);
System.out.println(reStr);
}
}Note: in the add method of the Calendar object, the second parameter is positive for "plus" and negative for "minus".
Code 2: java date date plus or minus days
Test class code:
import java.text.SimpleDateFormat;
import java.util.Date;
public class DateTest {
public static void main(String[] arg){
Date now = new Date();
addAndSubtractDaysByGetTime(now,-5);
addAndSubtractDaysByGetTime(now,5);
addAndSubtractDaysByCalendar(now,-5);
addAndSubtractDaysByCalendar(now,5);
}
public static Date addAndSubtractDaysByGetTime(Date dateTime/* Date to be processed */,int n/* Add and subtract the number */){
// The date format
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat dd=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println(df.format(new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L)));
//System.out.println(dd.format(new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L)));
// Note that there 1 It has to be converted into Long Type, or n More than 25 A range overflow occurs and you do not get the desired date value
return new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L);
}
public static Date addAndSubtractDaysByCalendar(Date dateTime/* Date to be processed */,int n/* Add and subtract the number */){
// The date format
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat dd=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
java.util.Calendar calstart = java.util.Calendar.getInstance();
calstart.setTime(dateTime);
calstart.add(java.util.Calendar.DAY_OF_WEEK, n);
System.out.println(df.format(calstart.getTime()));
//System.out.println(dd.format(calstart.getTime()));
return calstart.getTime();
}
}
Operation results:
2014-10-06
2014-10-16
2014-10-06
2014-10-16
Code 3:
Look it up on the Internet and add your own summary of the Date tools.
package com.data.utils;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class DateFormat {
/**
* Date minus a few years
*/
public static String dateMinusYear(String str) throws Exception {
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
Date dt = sdf.parse(str);
Calendar rightNow = Calendar.getInstance();
rightNow.setTime(dt);
rightNow.add(Calendar.YEAR, -1);// Date minus 1 years
Date dt1 = rightNow.getTime();
String reStr = sdf.format(dt1);
return reStr;
}
/**
* Date plus years
*/
public static String dateAddYear(String str) throws Exception {
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
Date dt = sdf.parse(str);
Calendar rightNow = Calendar.getInstance();
rightNow.setTime(dt);
rightNow.add(Calendar.YEAR, 1);// The date and 1 years
Date dt1 = rightNow.getTime();
String reStr = sdf.format(dt1);
return reStr;
}
/**
* Subtract a few months from the date
*/
public static String dateMinusMonth(String str) throws Exception {
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
Date dt = sdf.parse(str);// Generate the string Date
Calendar rightNow = Calendar.getInstance();
rightNow.setTime(dt);// Using a given Date Set this Calendar The time.
rightNow.add(Calendar.MONTH, -1);// Date minus 1 months
Date dt1 = rightNow.getTime();// return 1 A said this Calendar The time value of Date Object.
String reStr = sdf.format(dt1);// Will be given Date Formatted as a date / Time string and add the result to the given StringBuffer .
return reStr;
}
/**
* Date plus months
*/
public static String dateAddMonth(String str) throws Exception {
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
Date dt = sdf.parse(str);
Calendar rightNow = Calendar.getInstance();
rightNow.setTime(dt);
rightNow.add(Calendar.MONTH, 1);// The date and 3 months
// rightNow.add(Calendar.DAY_OF_YEAR,10);// The date and 10 day
Date dt1 = rightNow.getTime();
String reStr = sdf.format(dt1);
return reStr;
}
/**
* Gets the date of the current month 1 Months of str
* @param str
* 201505
* @return 201501
* @throws Exception
*/
public static String dateOneMonth(String str) {
str = str.substring(0, str.length() - 2);
str = str + "01";
return str;
}
/**
* Figure out the distance of the selected month 1 Months have months.
* @param str 201509
* @return 9
*/
public static int dateDistanceMonth(String str) {
int i = Integer.parseInt(str);
int j = Integer.parseInt(DateFormat.dateOneMonth(str));
System.out.println(i - j);
return i - j + 1;
}
/**
* Get the time difference between the two times, accurate to milliseconds
* @param str
* @return
*/
public static String TimeDifference(long start, long end) {
long between = end - start;
long day = between / (24 * 60 * 60 * 1000);
long hour = (between / (60 * 60 * 1000) - day * 24);
long min = ((between / (60 * 1000)) - day * 24 * 60 - hour * 60);
long s = (between / 1000 - day * 24 * 60 * 60 - hour * 60 * 60 - min * 60);
long ms = (between - day * 24 * 60 * 60 * 1000 - hour * 60 * 60 * 1000
- min * 60 * 1000 - s * 1000);
String timeDifference = day + " day " + hour + " hours " + min + " points " + s + " seconds " + ms
+ " ms ";
return timeDifference;
}
}
/**
* To obtain 24 Hours, 1 Weeks, 1 Month starting time
*
* @param timeInterval
* : DAY_TIME_INTERVAL WEEK_TIME_INTERVAL MONTH_TIME_INTERVAL
* @return "yyyy-mm-dd hh:mm:ss"
*/
public static String getStartTime(int timeInterval) {
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
if (DAY_TIME_INTERVAL == timeInterval) {// To obtain 24 Hour starting time
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
String startTime = sdf.format(cal.getTime());
return startTime;
} else if (WEEK_TIME_INTERVAL == timeInterval) {
int weekday = cal.get(Calendar.DAY_OF_WEEK) - 1;
cal.add(Calendar.DATE, -weekday);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
String startTime = sdf.format(cal.getTime());
return startTime;
} else if (MONTH_TIME_INTERVAL == timeInterval) {
int dayofmonthMin = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
// c.add(Calendar.DATE, -dayofmonth);
cal.set(Calendar.DATE, dayofmonthMin);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
String startTime = sdf.format(cal.getTime());
return startTime;
}
return null;
}
/**
* To obtain 24 Hours, 1 Weeks, 1 End of month
*
* @param timeInterval
* : DAY_TIME_INTERVAL WEEK_TIME_INTERVAL MONTH_TIME_INTERVAL
* @return "yyyy-mm-dd hh:mm:ss"
*/
public static String getEndTime(int timeInterval) {
Calendar cal = Calendar.getInstance();
cal.setTimeZone(TimeZone.getTimeZone("GMT+8"));
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
if (DAY_TIME_INTERVAL == timeInterval) {
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(12, 59);
cal.set(13, 59);
long date = cal.getTimeInMillis();
String endTime = sdf.format(new Date(date));
return endTime;
} else if (WEEK_TIME_INTERVAL == timeInterval) {
int weekday = cal.get(Calendar.DAY_OF_WEEK) - 1;
cal.add(Calendar.DATE, -weekday);
cal.add(Calendar.DATE, 6);
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(12, 59);
cal.set(13, 59);
long date = cal.getTimeInMillis();
String endTime = sdf.format(new Date(date));
return endTime;
} else if (MONTH_TIME_INTERVAL == timeInterval) {
int dayOfMonthMax = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
cal.set(Calendar.DATE, dayOfMonthMax);
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(Calendar.MINUTE, 59);
cal.set(Calendar.SECOND, 59);
String endTime = sdf.format(cal.getTime());
return endTime;
}
return null;
}
/**
* judge dateStr Whether in start and end In the middle, start and end Can be for null yyyyMMddHHmmss or yyyyMMdd format
*
* @author you.xu
* @date 2015 years 8 month 19 On the afternoon 3:11:46
* @param dateStr
* @param start
* @param end
* @return
*/
public static boolean checkDateVal(String dateStr, String start, String end) {
boolean isDateRight = false;
Date date = null;
Date startDate = null;
Date endDate = null;
SimpleDateFormat sdf = null;
// Determine the date format
if (14 == dateStr.length()) {
sdf = new SimpleDateFormat("yyyyMMddHHmmss");
} else if (8 == dateStr.length()) {
sdf = new SimpleDateFormat("yyyyMMdd");
} else
return false;
try {
// Change the date determination format
date = sdf.parse(dateStr);
} catch (ParseException e) {
log.error(e, e);
}
if ((start == null) && (end != null)) {
try {
endDate = sdf.parse(end);
} catch (ParseException ex1) {
log.error(ex1, ex1);
}
if ((date != null) && (endDate != null))// Check parameters for
{
if (date.compareTo(endDate) <= 0)
isDateRight = true;
}
} else if ((start != null) && (end == null)) {
try {
startDate = sdf.parse(start);
} catch (ParseException ex1) {
log.error(ex1, ex1);
}
if ((date != null) && (startDate != null)) {
if (date.compareTo(startDate) >= 0)
isDateRight = true;
}
} else if ((start != null) && (end != null)) {
try {
startDate = sdf.parse(start);
endDate = sdf.parse(end);
} catch (ParseException ex2) {
System.out.println(ex2.toString());
}
if ((startDate != null) && (date != null) && (endDate != null)) {
if ((date.compareTo(startDate) >= 0)
&& (date.compareTo(endDate) <= 0))
isDateRight = true;
}
}
return isDateRight;
}
/**
* judge dateStr Whether in start and end In the middle, start and end Can be for null long Image format
*
* @author you.xu
* @date 2015 years 8 month 19 On the afternoon 3:12:35
* @param dateStr
* @param start
* @param end
* @return
*/
public static boolean checkDateV(String dateStr, String start, String end) {
boolean isDateRight = false;
long date = -1;
long fromDate = -1;
long toDate = -1;
date = java.lang.Long.parseLong(dateStr);
if ((start == null) && (end == null)) {
isDateRight = true;
} else if ((start == null) && (end != null)) {
try {
toDate = java.lang.Long.parseLong(end);
} catch (NumberFormatException nfe) {
log.error(nfe, nfe);
}
if (date <= toDate) {
isDateRight = true;
}
} else if ((start != null) && (end == null)) {
try {
fromDate = java.lang.Long.parseLong(start);
} catch (NumberFormatException nfe) {
log.error(nfe, nfe);
}
if (date >= fromDate) {
isDateRight = true;
}
} else if ((start != null) && (end != null)) {
try {
toDate = java.lang.Long.parseLong(end);
fromDate = java.lang.Long.parseLong(start);
} catch (NumberFormatException nfe) {
log.error(nfe, nfe);
}
if ((date <= toDate) && (date >= fromDate)) {
isDateRight = true;
}
}
return isDateRight;
}So far, I have used these, and I can add them at any time. There is a simple and convenient time tool class. I hope to learn from you, and I will point out in the comments. thanks!!!!!!