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Java에서 정규식 날짜 형식 유효성 검사
Java 데스크톱 앱의 입력이 "YYYY-MM-DD"형식의 문자열인지 확인하는 방법 (정규식 사용)이 있는지 궁금합니다.
검색했지만 성공하지 못했습니다.
감사합니다
다음 정규식을 사용하십시오.
^\d{4}-\d{2}-\d{2}$
에서와 같이
if (str.matches("\\d{4}-\\d{2}-\\d{2}")) {
...
}
로 matches에있어서, 상기 앵커 ^및 $(문자열의 시작과 끝에 각각) 내재적으로 존재한다.
이상이 필요 regex합니다. 예를 들어 '9999-99-00'은 유효한 날짜가 아닙니다. 있어 SimpleDateFormat이 작업을 수행하기 위해 내장의 클래스는. 더 무겁지만 더 포괄적입니다.
예 :
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
boolean isValidDate(string input) {
try {
format.parse(input);
return true;
}
catch(ParseException e){
return false;
}
}
불행히도 SimpleDateFormat무겁고 스레드로부터 안전하지 않습니다.
함께 모아서:
REGEX값의 유효성을 검사하지 않음 (예 : "2010-19-19")SimpleDateFormat형식을 확인하지 않음 ( "2010-1-2", "1-0002-003"허용됨)
형식과 값의 유효성을 검사하려면 둘 다 사용해야합니다.
public static boolean isValid(String text) {
if (text == null || !text.matches("\\d{4}-[01]\\d-[0-3]\\d"))
return false;
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
df.setLenient(false);
try {
df.parse(text);
return true;
} catch (ParseException ex) {
return false;
}
}
ThreadLocal을 사용하여 각 호출에 대한 새 SimpleDateFormat 생성을 방지 할 수 있습니다.
SimpleDateFormat은 스레드로부터 안전하지 않기 때문에 다중 스레드 컨텍스트에서 필요합니다.
private static final ThreadLocal<SimpleDateFormat> format = new ThreadLocal<SimpleDateFormat>() {
@Override
protected SimpleDateFormat initialValue() {
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
df.setLenient(false);
System.out.println("created");
return df;
}
};
public static boolean isValid(String text) {
if (text == null || !text.matches("\\d{4}-[01]\\d-[0-3]\\d"))
return false;
try {
format.get().parse(text);
return true;
} catch (ParseException ex) {
return false;
}
}
(Matcher도 스레드로부터 안전하지 않습니다.)
정규식 : "^((19|20)\\d\\d)-(0?[1-9]|1[012])-(0?[1-9]|[12][0-9]|3[01])$"유효한 형식과 유효한 날짜를 처리합니다. 윤년과 같은 월의 정확한 날짜를 확인하지 않습니다.
String regex = "^((19|20)\\d\\d)-(0?[1-9]|1[012])-(0?[1-9]|[12][0-9]|3[01])$";
Assert.assertTrue("Date: matched.", Pattern.matches(regex, "2011-1-1"));
Assert.assertFalse("Date (month): not matched.", Pattern.matches(regex, "2011-13-1"));
행운을 빕니다!
나는 일이 31 일 이상 12 개월 이하인지 확인하는 간단한 정규식으로 갈 것입니다.
(0?[1-9]|[12][0-9]|3[01])-(0?[1-9]|1[012])-((18|19|20|21)\\d\\d)
"dd-MM-yyyy"형식입니다. 필요에 맞게 조정할 수 있습니다 (예 : 선행 0을 필수로 만들기 위해?를 제거-이제 선택 사항), 사용자 정의 논리를 사용하여 윤년 2 월 일수 케이스 및 기타 개월 수 일 경우. 아래의 DateChecker 코드를 참조하십시오.
성능을 고려할 때 이것이 가장 좋은 방법임을 테스트했기 때문에이 방법을 선택하고 있습니다. 나는이 (첫 번째) 접근 방식과 다른 사용 사례를 처리하는 정규식에 대해 날짜를 확인하는 두 번째 접근 방식과 SimpleDateFormat.parse (date)와 함께 위의 동일한 간단한 정규식을 사용하는 세 번째 접근 방식을 확인했습니다.
1 차 접근 방식은 2 차 접근 방식보다 4 배, 3 차 접근 방식보다 8 배 빠릅니다. 하단의 자체 포함 된 날짜 검사기 및 성능 테스터 메인 클래스를 참조하십시오. 내가 확인하지 않은 한 가지는 joda time 접근 방식입니다. (보다 효율적인 날짜 / 시간 라이브러리).
날짜 검사기 코드 :
class DateChecker {
private Matcher matcher;
private Pattern pattern;
public DateChecker(String regex) {
pattern = Pattern.compile(regex);
}
/**
* Checks if the date format is a valid.
* Uses the regex pattern to match the date first.
* Than additionally checks are performed on the boundaries of the days taken the month into account (leap years are covered).
*
* @param date the date that needs to be checked.
* @return if the date is of an valid format or not.
*/
public boolean check(final String date) {
matcher = pattern.matcher(date);
if (matcher.matches()) {
matcher.reset();
if (matcher.find()) {
int day = Integer.parseInt(matcher.group(1));
int month = Integer.parseInt(matcher.group(2));
int year = Integer.parseInt(matcher.group(3));
switch (month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: return day < 32;
case 4:
case 6:
case 9:
case 11: return day < 31;
case 2:
int modulo100 = year % 100;
//http://science.howstuffworks.com/science-vs-myth/everyday-myths/question50.htm
if ((modulo100 == 0 && year % 400 == 0) || (modulo100 != 0 && year % LEAP_STEP == 0)) {
//its a leap year
return day < 30;
} else {
return day < 29;
}
default:
break;
}
}
}
return false;
}
public String getRegex() {
return pattern.pattern();
}
}
날짜 확인 / 테스트 및 성능 테스트 :
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Tester {
private static final String[] validDateStrings = new String[]{
"1-1-2000", //leading 0s for day and month optional
"01-1-2000", //leading 0 for month only optional
"1-01-2000", //leading 0 for day only optional
"01-01-1800", //first accepted date
"31-12-2199", //last accepted date
"31-01-2000", //January has 31 days
"31-03-2000", //March has 31 days
"31-05-2000", //May has 31 days
"31-07-2000", //July has 31 days
"31-08-2000", //August has 31 days
"31-10-2000", //October has 31 days
"31-12-2000", //December has 31 days
"30-04-2000", //April has 30 days
"30-06-2000", //June has 30 days
"30-09-2000", //September has 30 days
"30-11-2000", //November has 30 days
};
private static final String[] invalidDateStrings = new String[]{
"00-01-2000", //there is no 0-th day
"01-00-2000", //there is no 0-th month
"31-12-1799", //out of lower boundary date
"01-01-2200", //out of high boundary date
"32-01-2000", //January doesn't have 32 days
"32-03-2000", //March doesn't have 32 days
"32-05-2000", //May doesn't have 32 days
"32-07-2000", //July doesn't have 32 days
"32-08-2000", //August doesn't have 32 days
"32-10-2000", //October doesn't have 32 days
"32-12-2000", //December doesn't have 32 days
"31-04-2000", //April doesn't have 31 days
"31-06-2000", //June doesn't have 31 days
"31-09-2000", //September doesn't have 31 days
"31-11-2000", //November doesn't have 31 days
"001-02-2000", //SimpleDateFormat valid date (day with leading 0s) even with lenient set to false
"1-0002-2000", //SimpleDateFormat valid date (month with leading 0s) even with lenient set to false
"01-02-0003", //SimpleDateFormat valid date (year with leading 0s) even with lenient set to false
"01.01-2000", //. invalid separator between day and month
"01-01.2000", //. invalid separator between month and year
"01/01-2000", /// invalid separator between day and month
"01-01/2000", /// invalid separator between month and year
"01_01-2000", //_ invalid separator between day and month
"01-01_2000", //_ invalid separator between month and year
"01-01-2000-12345", //only whole string should be matched
"01-13-2000", //month bigger than 13
};
/**
* These constants will be used to generate the valid and invalid boundary dates for the leap years. (For no leap year, Feb. 28 valid and Feb. 29 invalid; for a leap year Feb. 29 valid and Feb. 30 invalid)
*/
private static final int LEAP_STEP = 4;
private static final int YEAR_START = 1800;
private static final int YEAR_END = 2199;
/**
* This date regex will find matches for valid dates between 1800 and 2199 in the format of "dd-MM-yyyy".
* The leading 0 is optional.
*/
private static final String DATE_REGEX = "((0?[1-9]|[12][0-9]|3[01])-(0?[13578]|1[02])-(18|19|20|21)[0-9]{2})|((0?[1-9]|[12][0-9]|30)-(0?[469]|11)-(18|19|20|21)[0-9]{2})|((0?[1-9]|1[0-9]|2[0-8])-(0?2)-(18|19|20|21)[0-9]{2})|(29-(0?2)-(((18|19|20|21)(04|08|[2468][048]|[13579][26]))|2000))";
/**
* This date regex is similar to the first one, but with the difference of matching only the whole string. So "01-01-2000-12345" won't pass with a match.
* Keep in mind that String.matches tries to match only the whole string.
*/
private static final String DATE_REGEX_ONLY_WHOLE_STRING = "^" + DATE_REGEX + "$";
/**
* The simple regex (without checking for 31 day months and leap years):
*/
private static final String DATE_REGEX_SIMPLE = "(0?[1-9]|[12][0-9]|3[01])-(0?[1-9]|1[012])-((18|19|20|21)\\d\\d)";
/**
* This date regex is similar to the first one, but with the difference of matching only the whole string. So "01-01-2000-12345" won't pass with a match.
*/
private static final String DATE_REGEX_SIMPLE_ONLY_WHOLE_STRING = "^" + DATE_REGEX_SIMPLE + "$";
private static final SimpleDateFormat SDF = new SimpleDateFormat("dd-MM-yyyy");
static {
SDF.setLenient(false);
}
private static final DateChecker dateValidatorSimple = new DateChecker(DATE_REGEX_SIMPLE);
private static final DateChecker dateValidatorSimpleOnlyWholeString = new DateChecker(DATE_REGEX_SIMPLE_ONLY_WHOLE_STRING);
/**
* @param args
*/
public static void main(String[] args) {
DateTimeStatistics dateTimeStatistics = new DateTimeStatistics();
boolean shouldMatch = true;
for (int i = 0; i < validDateStrings.length; i++) {
String validDate = validDateStrings[i];
matchAssertAndPopulateTimes(
dateTimeStatistics,
shouldMatch, validDate);
}
shouldMatch = false;
for (int i = 0; i < invalidDateStrings.length; i++) {
String invalidDate = invalidDateStrings[i];
matchAssertAndPopulateTimes(dateTimeStatistics,
shouldMatch, invalidDate);
}
for (int year = YEAR_START; year < (YEAR_END + 1); year++) {
FebruaryBoundaryDates februaryBoundaryDates = createValidAndInvalidFebruaryBoundaryDateStringsFromYear(year);
shouldMatch = true;
matchAssertAndPopulateTimes(dateTimeStatistics,
shouldMatch, februaryBoundaryDates.getValidFebruaryBoundaryDateString());
shouldMatch = false;
matchAssertAndPopulateTimes(dateTimeStatistics,
shouldMatch, februaryBoundaryDates.getInvalidFebruaryBoundaryDateString());
}
dateTimeStatistics.calculateAvarageTimesAndPrint();
}
private static void matchAssertAndPopulateTimes(
DateTimeStatistics dateTimeStatistics,
boolean shouldMatch, String date) {
dateTimeStatistics.addDate(date);
matchAndPopulateTimeToMatch(date, DATE_REGEX, shouldMatch, dateTimeStatistics.getTimesTakenWithDateRegex());
matchAndPopulateTimeToMatch(date, DATE_REGEX_ONLY_WHOLE_STRING, shouldMatch, dateTimeStatistics.getTimesTakenWithDateRegexOnlyWholeString());
boolean matchesSimpleDateFormat = matchWithSimpleDateFormatAndPopulateTimeToMatchAndReturnMatches(date, dateTimeStatistics.getTimesTakenWithSimpleDateFormatParse());
matchAndPopulateTimeToMatchAndReturnMatchesAndCheck(
dateTimeStatistics.getTimesTakenWithDateRegexSimple(), shouldMatch,
date, matchesSimpleDateFormat, DATE_REGEX_SIMPLE);
matchAndPopulateTimeToMatchAndReturnMatchesAndCheck(
dateTimeStatistics.getTimesTakenWithDateRegexSimpleOnlyWholeString(), shouldMatch,
date, matchesSimpleDateFormat, DATE_REGEX_SIMPLE_ONLY_WHOLE_STRING);
matchAndPopulateTimeToMatch(date, dateValidatorSimple, shouldMatch, dateTimeStatistics.getTimesTakenWithdateValidatorSimple());
matchAndPopulateTimeToMatch(date, dateValidatorSimpleOnlyWholeString, shouldMatch, dateTimeStatistics.getTimesTakenWithdateValidatorSimpleOnlyWholeString());
}
private static void matchAndPopulateTimeToMatchAndReturnMatchesAndCheck(
List<Long> times,
boolean shouldMatch, String date, boolean matchesSimpleDateFormat, String regex) {
boolean matchesFromRegex = matchAndPopulateTimeToMatchAndReturnMatches(date, regex, times);
assert !((matchesSimpleDateFormat && matchesFromRegex) ^ shouldMatch) : "Parsing with SimpleDateFormat and date:" + date + "\nregex:" + regex + "\nshouldMatch:" + shouldMatch;
}
private static void matchAndPopulateTimeToMatch(String date, String regex, boolean shouldMatch, List<Long> times) {
boolean matches = matchAndPopulateTimeToMatchAndReturnMatches(date, regex, times);
assert !(matches ^ shouldMatch) : "date:" + date + "\nregex:" + regex + "\nshouldMatch:" + shouldMatch;
}
private static void matchAndPopulateTimeToMatch(String date, DateChecker dateValidator, boolean shouldMatch, List<Long> times) {
long timestampStart;
long timestampEnd;
boolean matches;
timestampStart = System.nanoTime();
matches = dateValidator.check(date);
timestampEnd = System.nanoTime();
times.add(timestampEnd - timestampStart);
assert !(matches ^ shouldMatch) : "date:" + date + "\ndateValidator with regex:" + dateValidator.getRegex() + "\nshouldMatch:" + shouldMatch;
}
private static boolean matchAndPopulateTimeToMatchAndReturnMatches(String date, String regex, List<Long> times) {
long timestampStart;
long timestampEnd;
boolean matches;
timestampStart = System.nanoTime();
matches = date.matches(regex);
timestampEnd = System.nanoTime();
times.add(timestampEnd - timestampStart);
return matches;
}
private static boolean matchWithSimpleDateFormatAndPopulateTimeToMatchAndReturnMatches(String date, List<Long> times) {
long timestampStart;
long timestampEnd;
boolean matches = true;
timestampStart = System.nanoTime();
try {
SDF.parse(date);
} catch (ParseException e) {
matches = false;
} finally {
timestampEnd = System.nanoTime();
times.add(timestampEnd - timestampStart);
}
return matches;
}
private static FebruaryBoundaryDates createValidAndInvalidFebruaryBoundaryDateStringsFromYear(int year) {
FebruaryBoundaryDates februaryBoundaryDates;
int modulo100 = year % 100;
//http://science.howstuffworks.com/science-vs-myth/everyday-myths/question50.htm
if ((modulo100 == 0 && year % 400 == 0) || (modulo100 != 0 && year % LEAP_STEP == 0)) {
februaryBoundaryDates = new FebruaryBoundaryDates(
createFebruaryDateFromDayAndYear(29, year),
createFebruaryDateFromDayAndYear(30, year)
);
} else {
februaryBoundaryDates = new FebruaryBoundaryDates(
createFebruaryDateFromDayAndYear(28, year),
createFebruaryDateFromDayAndYear(29, year)
);
}
return februaryBoundaryDates;
}
private static String createFebruaryDateFromDayAndYear(int day, int year) {
return String.format("%d-02-%d", day, year);
}
static class FebruaryBoundaryDates {
private String validFebruaryBoundaryDateString;
String invalidFebruaryBoundaryDateString;
public FebruaryBoundaryDates(String validFebruaryBoundaryDateString,
String invalidFebruaryBoundaryDateString) {
super();
this.validFebruaryBoundaryDateString = validFebruaryBoundaryDateString;
this.invalidFebruaryBoundaryDateString = invalidFebruaryBoundaryDateString;
}
public String getValidFebruaryBoundaryDateString() {
return validFebruaryBoundaryDateString;
}
public void setValidFebruaryBoundaryDateString(
String validFebruaryBoundaryDateString) {
this.validFebruaryBoundaryDateString = validFebruaryBoundaryDateString;
}
public String getInvalidFebruaryBoundaryDateString() {
return invalidFebruaryBoundaryDateString;
}
public void setInvalidFebruaryBoundaryDateString(
String invalidFebruaryBoundaryDateString) {
this.invalidFebruaryBoundaryDateString = invalidFebruaryBoundaryDateString;
}
}
static class DateTimeStatistics {
private List<String> dates = new ArrayList<String>();
private List<Long> timesTakenWithDateRegex = new ArrayList<Long>();
private List<Long> timesTakenWithDateRegexOnlyWholeString = new ArrayList<Long>();
private List<Long> timesTakenWithDateRegexSimple = new ArrayList<Long>();
private List<Long> timesTakenWithDateRegexSimpleOnlyWholeString = new ArrayList<Long>();
private List<Long> timesTakenWithSimpleDateFormatParse = new ArrayList<Long>();
private List<Long> timesTakenWithdateValidatorSimple = new ArrayList<Long>();
private List<Long> timesTakenWithdateValidatorSimpleOnlyWholeString = new ArrayList<Long>();
public List<String> getDates() {
return dates;
}
public List<Long> getTimesTakenWithDateRegex() {
return timesTakenWithDateRegex;
}
public List<Long> getTimesTakenWithDateRegexOnlyWholeString() {
return timesTakenWithDateRegexOnlyWholeString;
}
public List<Long> getTimesTakenWithDateRegexSimple() {
return timesTakenWithDateRegexSimple;
}
public List<Long> getTimesTakenWithDateRegexSimpleOnlyWholeString() {
return timesTakenWithDateRegexSimpleOnlyWholeString;
}
public List<Long> getTimesTakenWithSimpleDateFormatParse() {
return timesTakenWithSimpleDateFormatParse;
}
public List<Long> getTimesTakenWithdateValidatorSimple() {
return timesTakenWithdateValidatorSimple;
}
public List<Long> getTimesTakenWithdateValidatorSimpleOnlyWholeString() {
return timesTakenWithdateValidatorSimpleOnlyWholeString;
}
public void addDate(String date) {
dates.add(date);
}
public void addTimesTakenWithDateRegex(long time) {
timesTakenWithDateRegex.add(time);
}
public void addTimesTakenWithDateRegexOnlyWholeString(long time) {
timesTakenWithDateRegexOnlyWholeString.add(time);
}
public void addTimesTakenWithDateRegexSimple(long time) {
timesTakenWithDateRegexSimple.add(time);
}
public void addTimesTakenWithDateRegexSimpleOnlyWholeString(long time) {
timesTakenWithDateRegexSimpleOnlyWholeString.add(time);
}
public void addTimesTakenWithSimpleDateFormatParse(long time) {
timesTakenWithSimpleDateFormatParse.add(time);
}
public void addTimesTakenWithdateValidatorSimple(long time) {
timesTakenWithdateValidatorSimple.add(time);
}
public void addTimesTakenWithdateValidatorSimpleOnlyWholeString(long time) {
timesTakenWithdateValidatorSimpleOnlyWholeString.add(time);
}
private void calculateAvarageTimesAndPrint() {
long[] sumOfTimes = new long[7];
int timesSize = timesTakenWithDateRegex.size();
for (int i = 0; i < timesSize; i++) {
sumOfTimes[0] += timesTakenWithDateRegex.get(i);
sumOfTimes[1] += timesTakenWithDateRegexOnlyWholeString.get(i);
sumOfTimes[2] += timesTakenWithDateRegexSimple.get(i);
sumOfTimes[3] += timesTakenWithDateRegexSimpleOnlyWholeString.get(i);
sumOfTimes[4] += timesTakenWithSimpleDateFormatParse.get(i);
sumOfTimes[5] += timesTakenWithdateValidatorSimple.get(i);
sumOfTimes[6] += timesTakenWithdateValidatorSimpleOnlyWholeString.get(i);
}
System.out.println("AVG from timesTakenWithDateRegex (in nanoseconds):" + (double) sumOfTimes[0] / timesSize);
System.out.println("AVG from timesTakenWithDateRegexOnlyWholeString (in nanoseconds):" + (double) sumOfTimes[1] / timesSize);
System.out.println("AVG from timesTakenWithDateRegexSimple (in nanoseconds):" + (double) sumOfTimes[2] / timesSize);
System.out.println("AVG from timesTakenWithDateRegexSimpleOnlyWholeString (in nanoseconds):" + (double) sumOfTimes[3] / timesSize);
System.out.println("AVG from timesTakenWithSimpleDateFormatParse (in nanoseconds):" + (double) sumOfTimes[4] / timesSize);
System.out.println("AVG from timesTakenWithDateRegexSimple + timesTakenWithSimpleDateFormatParse (in nanoseconds):" + (double) (sumOfTimes[2] + sumOfTimes[4]) / timesSize);
System.out.println("AVG from timesTakenWithDateRegexSimpleOnlyWholeString + timesTakenWithSimpleDateFormatParse (in nanoseconds):" + (double) (sumOfTimes[3] + sumOfTimes[4]) / timesSize);
System.out.println("AVG from timesTakenWithdateValidatorSimple (in nanoseconds):" + (double) sumOfTimes[5] / timesSize);
System.out.println("AVG from timesTakenWithdateValidatorSimpleOnlyWholeString (in nanoseconds):" + (double) sumOfTimes[6] / timesSize);
}
}
static class DateChecker {
private Matcher matcher;
private Pattern pattern;
public DateChecker(String regex) {
pattern = Pattern.compile(regex);
}
/**
* Checks if the date format is a valid.
* Uses the regex pattern to match the date first.
* Than additionally checks are performed on the boundaries of the days taken the month into account (leap years are covered).
*
* @param date the date that needs to be checked.
* @return if the date is of an valid format or not.
*/
public boolean check(final String date) {
matcher = pattern.matcher(date);
if (matcher.matches()) {
matcher.reset();
if (matcher.find()) {
int day = Integer.parseInt(matcher.group(1));
int month = Integer.parseInt(matcher.group(2));
int year = Integer.parseInt(matcher.group(3));
switch (month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: return day < 32;
case 4:
case 6:
case 9:
case 11: return day < 31;
case 2:
int modulo100 = year % 100;
//http://science.howstuffworks.com/science-vs-myth/everyday-myths/question50.htm
if ((modulo100 == 0 && year % 400 == 0) || (modulo100 != 0 && year % LEAP_STEP == 0)) {
//its a leap year
return day < 30;
} else {
return day < 29;
}
default:
break;
}
}
}
return false;
}
public String getRegex() {
return pattern.pattern();
}
}
}
Some useful notes:
- to enable the assertions (assert checks) you need to use -ea argument when running the tester. (In eclipse this is done by editing the Run/Debug configuration -> Arguments tab -> VM Arguments -> insert "-ea"
- the regex above is bounded to years 1800 to 2199
- you don't need to use ^ at the beginning and $ at the end to match only the whole date string. The String.matches takes care of that.
- make sure u check the valid and invalid cases and change them according the rules that you have.
- the "only whole string" version of each regex gives the same speed as the "normal" version (the one without ^ and $). If you see performance differences this is because java "gets used" to processing the same instructions so the time lowers. If you switch the lines where the "normal" and the "only whole string" version execute, you will see this proven.
Hope this helps someone!
Cheers,
Despot
java.time
The proper (and easy) way to do date/time validation using Java 8+ is to use the java.time.format.DateTimeFormatter class. Using a regex for validation isn't really ideal for dates. For the example case in this question:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
try {
LocalDate date = formatter.parse(text, LocalDate::from);
} catch (DateTimeParseException e) {
// Thrown if text could not be parsed in the specified format
}
This code will parse the text, validate that it is a valid date, and also return the date as a LocalDate object. Note that the DateTimeFormatter class has a number of static predefined date formats matching ISO standards if your use case matches any of them.
Construct a SimpleDateFormat with the mask, and then call: SimpleDateFormat.parse(String s, ParsePosition p)
For fine control, consider an InputVerifier using the SimpleDateFormat("YYYY-MM-dd") suggested by Steve B.
If you want a simple regex then it won't be accurate. https://www.freeformatter.com/java-regex-tester.html#ad-output offers a tool to test your Java regex. Also, at the bottom you can find some suggested regexes for validating a date.
ISO date format (yyyy-mm-dd):
^[0-9]{4}-(((0[13578]|(10|12))-(0[1-9]|[1-2][0-9]|3[0-1]))|(02-(0[1-9]|[1-2][0-9]))|((0[469]|11)-(0[1-9]|[1-2][0-9]|30)))$
ISO date format (yyyy-mm-dd) with separators '-' or '/' or '.' or ' '. Forces usage of same separator accross date.
^[0-9]{4}([- /.])(((0[13578]|(10|12))\1(0[1-9]|[1-2][0-9]|3[0-1]))|(02\1(0[1-9]|[1-2][0-9]))|((0[469]|11)\1(0[1-9]|[1-2][0-9]|30)))$
United States date format (mm/dd/yyyy)
^(((0[13578]|(10|12))/(0[1-9]|[1-2][0-9]|3[0-1]))|(02/(0[1-9]|[1-2][0-9]))|((0[469]|11)/(0[1-9]|[1-2][0-9]|30)))/[0-9]{4}$
Hours and minutes, 24 hours format (HH:MM):
^(20|21|22|23|[01]\d|\d)((:[0-5]\d){1,2})$
Good luck
Below added code is working for me if you are using pattern dd-MM-yyyy.
public boolean isValidDate(String date) {
boolean check;
String date1 = "^(0?[1-9]|[12][0-9]|3[01])-(0?[1-9]|1[012])-([12][0-9]{3})$";
check = date.matches(date1);
return check;
}
The following regex will accept YYYY-MM-DD (within the range 1600-2999 year) formatted dates taking into consideration leap years:
^((?:(?:1[6-9]|2[0-9])\d{2})(-)(?:(?:(?:0[13578]|1[02])(-)31)|((0[1,3-9]|1[0-2])(-)(29|30))))$|^(?:(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(-)02(-)29)$|^(?:(?:1[6-9]|2[0-9])\d{2})(-)(?:(?:0[1-9])|(?:1[0-2]))(-)(?:0[1-9]|1\d|2[0-8])$
Examples:
You can test it here.
Note: if you want to accept one digit as month or day you can use:
^((?:(?:1[6-9]|2[0-9])\d{2})(-)(?:(?:(?:0?[13578]|1[02])(-)31)|((0?[1,3-9]|1[0-2])(-)(29|30))))$|^(?:(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(-)0?2(-)29)$|^(?:(?:1[6-9]|2[0-9])\d{2})(-)(?:(?:0?[1-9])|(?:1[0-2]))(-)(?:0?[1-9]|1\d|2[0-8])$
I have created the above regex starting from this solution
ReferenceURL : https://stackoverflow.com/questions/2149680/regex-date-format-validation-on-java
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