Im trying to do a connection with a database in Java using OOP and DAO pattern with MySQL and need to validate a date string in java and insert it into MySQl, the connection is fine the problem is the validation. I have to use Strings in both because thats what i was asked for but it doesnt recognize months like february or the ones with 30 days i tried with a while but apparentrly it can be done with the method im usinng (TemporalAccesor for unary operator ERROR). I also have to calculate the age of the person based on that date but since is a string, i cant figure out how to connect it with the date of the computer.

Thanks for any help, really need it

Method that throws the exception but allows Feb-31 or Sep-31: I call it on the method where I fill all the other data and works well except for that detail Also tried a regex but i saw is not convenient and doesnt catch that either

private static void FechaNacV(){

String date;
        
        Scanner sc = new Scanner(System.in);
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu/MM/dd");
        date = sc.nextLine();
        try {

            formatter.parse(date);
            System.out.println("Valid date");
        } catch (Exception e) {
            
            System.out.println("Invalid Date, try yyyy/mm/dd format again");
            FechaNacV();
        }
    } 

CodePudding user response：

ResolverStyle.STRICT

The default resolver style in DateTimeFormatter will adjust your invalid 31st of February to the appropriate 28th or 29th.

If you want to avoid that tolerant adjustment, specify a different resolver style.

    DateTimeFormatter
        .ofPattern( "uuuu/MM/dd" )
        .withResolverStyle( ResolverStyle.STRICT ) ;  // Be strict: Reject 31st of February.

Call parse on the LocalDate class rather than the DateTimeFormatter class.

LocalDate ld = null ; 

String input = "2022/02/31" ;
DateTimeFormatter formatter = 
    DateTimeFormatter
        .ofPattern( "uuuu/MM/dd" )
        .withResolverStyle( ResolverStyle.STRICT ) ;  // Be strict: Reject 31st of February.
try {
    ld = LocalDate.parse( input , formatter ) ;
} catch ( DateTimeParseException e ) {
    System.out.println( e ) ;
}
System.out.println( ld ) ;

See this code run at Ideone.com.

java.time.format.DateTimeParseException: Text '2022/02/31' could not be parsed: Invalid date 'FEBRUARY 31'

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