我想编写一个代码来使用Java验证不同类型的日期，但带有T和Z的日期仍显示无效

Question

Here is the code that I have written

Please suggest me if anyone has ever tried something like this.

private static final String[] Date_Reg_Ex = {
        "yyyy-MM", "yyyy-MM-dd", "dd-MMMM-yyyy", "dd-MM-yyyy", "MM-dd-yyyy", "dd-MM-yyyy HH:mm:ss/SSS",
        "yyyy-MM-dd HH:mm", "yyyy-mm-dd'T'HH:MM:ss", "yyyy-MM-dd'T'HH:mm:ss.SSS",
        "yyyy-MM-dd HH:mm:ss.SSS", "yyyy-MM-dd HH:mm:ss", "yyyy-MM-dd HH:mm:ss.S", "yyyy-MM-dd'@'HH:mm:ss",
        "yyyy-MM-dd'/'K:mm a", "MM-dd-yyyy hh:mm a", "MM-dd-yyyy hh:mm:ss a", "hh:mm:ss MMM d, yyyy z",
        "EEEE dd/MM/yyyy", "EEE, dd MMM yyyy HH:mm:ss zzz", "EEE MMM dd hh:mm:ss z yyyy", "dd MMMMM yyyy",
        "MM/dd/yyyy HH:mm", "MM/YYYY", "MM/YY", "dd/MM/yyyy", "yyyy/MM/dd", "MMM, dd/yyyy", "dd.MM.yyyy", "MMM. dd",
        "yyyy", "yyyyMMdd", "MMddyyyy", "MMMM yyyy", "ddMMyyyyHHmmss", "yyyy"
};

public static boolean isValidDate(String value, TimeZone timeZone) {
    DateValidator dateValidator = DateValidator.getInstance();
    for (String dateRegEx : Date_Reg_Ex) {
        if (dateValidator.isValid(value, dateRegEx)) {
            return true;
        }
    }
    return false;
}

Answer 1

Since you wrote "dates with T and Z are still showing invalid", I suppose you mean:

1. "yyyy-mm-dd'T'HH:MM:ss"
2. "yyyy-MM-dd'T'HH:mm:ss.SSS"

and

3. "hh:mm:ss MMM d, yyyy z"
4. "EEE, dd MMM yyyy HH:mm:ss zzz"
5. "EEE MMM dd hh:mm:ss z yyyy"

I could not find any problems with 2,3,4 and 5. Date 1 however switches months and minutes which I guess is not intended.

Here are examples of dates that worked for me:

1. "yyyy- MM -dd'T'HH: mm :ss" -> "2019-09-12T13:21:31"
2. "yyyy-MM-dd'T'HH:mm:ss.SSS" -> "2019-09-12T13:21:31.020"
3. "hh:mm:ss MMM d, yyyy z" -> "1:21:31 Sep 12, 2019 PST"
4. "EEE, dd MMM yyyy HH:mm:ss zzz" -> "Thursday, 12 Sep 2019 13:21:31 PST"
5. "EEE MMM dd hh:mm:ss z yyyy" -> "Thursday Sep 12 1:21:31 PST 2019"

Answer 2

It could be related to your local, I tested some example from @Aio and had to force a specific default local to make it succeed I also applied his change to 8th pattern:

I used version 1.6 of Apache Commons Validator

private static final String[] Date_Reg_Ex = {
        "yyyy-MM", "yyyy-MM-dd", "dd-MMMM-yyyy", "dd-MM-yyyy", "MM-dd-yyyy", "dd-MM-yyyy HH:mm:ss/SSS",
        "yyyy-MM-dd HH:mm", "yyyy-MM-dd'T'HH:mm:ss" /** This has been updated as suggested by Aio **/, "yyyy-MM-dd'T'HH:mm:ss.SSS",
        "yyyy-MM-dd HH:mm:ss.SSS", "yyyy-MM-dd HH:mm:ss", "yyyy-MM-dd HH:mm:ss.S", "yyyy-MM-dd'@'HH:mm:ss",
        "yyyy-MM-dd'/'K:mm a", "MM-dd-yyyy hh:mm a", "MM-dd-yyyy hh:mm:ss a", "hh:mm:ss MMM d, yyyy z",
        "EEEE dd/MM/yyyy", "EEE, dd MMM yyyy HH:mm:ss zzz", "EEE MMM dd hh:mm:ss z yyyy", "dd MMMMM yyyy",
        "MM/dd/yyyy HH:mm", "MM/YYYY", "MM/YY", "dd/MM/yyyy", "yyyy/MM/dd", "MMM, dd/yyyy", "dd.MM.yyyy", "MMM. dd",
        "yyyy", "yyyyMMdd", "MMddyyyy", "MMMM yyyy", "ddMMyyyyHHmmss", "yyyy"
};

public static boolean isValidDate(String value, TimeZone timeZone) {
    DateValidator dateValidator = DateValidator.getInstance();
    for (String dateRegEx : Date_Reg_Ex) {
        if (dateValidator.isValid(value, dateRegEx)) {
            return true;
        }
    }
    return false;
}

public static void main(String... args) {
    // without the next line some tests fail
    Locale.setDefault(Locale.US);

    assertTrue("2019-09-12T13:21:31");
    assertTrue("2019-09-12T13:21:31.020");
    assertTrue("1:21:31 Sep 12, 2019 PST");
    assertTrue("Thursday, 12 Sep 2019 13:21:31 PST");
    assertTrue("Thursday Sep 12 1:21:31 PST 2019");
}

private static void assertTrue(String s) {
    if (!isValidDate(s, null)) {
        System.err.println("Not valid: " + s);
    } else {
        System.out.println("Valid: " + s);
    }
}

This gives me:

Valid: 2019-09-12T13:21:31
Valid: 2019-09-12T13:21:31.020
Valid: 1:21:31 Sep 12, 2019 PST
Valid: Thursday, 12 Sep 2019 13:21:31 PST
Valid: Thursday Sep 12 1:21:31 PST 2019

Process finished with exit code 0

Answer 3

I think there is a typo at yyyy-mm-dd'T'HH:MM:ss.

mm stands for minutes and MM stands for month, here it should be yyyy-MM-dd'T'HH:mm:ss.

Please try correcting it once, I hope you we get the desired result without any program/extra code.

Answer 4

I used SimpleDateFormat for this instead of any external Library, You can Validate the Date with simply parsing the date and checking an exception -

I suppose you can use something like this -

private static final String[] DATEFORMATS = {"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'","yyyy-MM-dd'T'HH:mm:ss'Z'",
        "dd-MM-yy HH:mm:ss","dd-MMM-yy HH:mm:ss","yyyy-MM-dd","yyyy-MMM-dd","dd-MMM-yyyy","dd-MM-yyyy"};


public static Date parseDate(String date ) {
    SimpleDateFormat sdf = new SimpleDateFormat();
    Date parsedDate = null;
    for(String format : DATEFORMATS) {
        try {
            sdf.applyPattern(format);
            parsedDate = sdf.parse(date);
            break;
        }catch(ParseException e) {
            LOG.debug("parseDate:: Not in format::{} Moving to next ",format);
        }
    }
    return parsedDate;
}