JDK踩坑: Smart LocalDate

LocalDate.parse(param.getEndDate())

java.time.format.DateTimeParseException: Text '2020-06-31' could not be parsed: Invalid date 'JUNE 31'

public static final DateTimeFormatter dateTimeFormat = DateTimeFormatter.ofPattern("yyyy-MM-dd");public static boolean isDateTimeFormat2(String date) {    String regex = "[0-9]{4}-[0-9]{2}-[0-9]{2}";    Pattern pattern = Pattern.compile(regex);    Matcher m = pattern.matcher(date);    boolean dateFlag = m.matches();    if (!dateFlag) {        return false;    } else {        try {            LocalDate.parse(date, dateTimeFormat);            return true;        } catch (DateTimeParseException var6) {            return false;        }    }}

/** * Obtains an instance of {@code LocalDate} from a text string such as {@code 2007-12-03}. * <p> * The string must represent a valid date and is parsed using * {@link java.time.format.DateTimeFormatter#ISO_LOCAL_DATE}. * * @param text  the text to parse such as "2007-12-03", not null * @return the parsed local date, not null * @throws DateTimeParseException if the text cannot be parsed */public static LocalDate parse(CharSequence text) {    return parse(text, DateTimeFormatter.ISO_LOCAL_DATE);}/** * Obtains an instance of {@code LocalDate} from a text string using a specific formatter. * <p> * The text is parsed using the formatter, returning a date. * * @param text  the text to parse, not null * @param formatter  the formatter to use, not null * @return the parsed local date, not null * @throws DateTimeParseException if the text cannot be parsed */public static LocalDate parse(CharSequence text, DateTimeFormatter formatter) {    Objects.requireNonNull(formatter, "formatter");    return formatter.parse(text, LocalDate::from);}

/** * Creates a formatter using the specified pattern. * <p> * This method will create a formatter based on a simple * <a href="#patterns">pattern of letters and symbols</a> * as described in the class documentation. * For example, {@code d MMM uuuu} will format 2011-12-03 as '3 Dec 2011'. * <p> * The formatter will use the {@link Locale#getDefault(Locale.Category) default FORMAT locale}. * This can be changed using {@link DateTimeFormatter#withLocale(Locale)} on the returned formatter * Alternatively use the {@link #ofPattern(String, Locale)} variant of this method. * <p> * The returned formatter has no override chronology or zone. * It uses {@link ResolverStyle#SMART SMART} resolver style. * * @param pattern  the pattern to use, not null * @return the formatter based on the pattern, not null * @throws IllegalArgumentException if the pattern is invalid * @see DateTimeFormatterBuilder#appendPattern(String) */public static DateTimeFormatter ofPattern(String pattern) {    return new DateTimeFormatterBuilder().appendPattern(pattern).toFormatter();}

It uses {@link ResolverStyle#SMART SMART} resolver style.

public enum ResolverStyle {    /**     * Style to resolve dates and times strictly.     * <p>     * Using strict resolution will ensure that all parsed values are within     * the outer range of valid values for the field. Individual fields may     * be further processed for strictness.     * <p>     * For example, resolving year-month and day-of-month in the ISO calendar     * system using strict mode will ensure that the day-of-month is valid     * for the year-month, rejecting invalid values.     */    STRICT,    /**     * Style to resolve dates and times in a smart, or intelligent, manner.     * <p>     * Using smart resolution will perform the sensible default for each     * field, which may be the same as strict, the same as lenient, or a third     * behavior. Individual fields will interpret this differently.     * <p>     * For example, resolving year-month and day-of-month in the ISO calendar     * system using smart mode will ensure that the day-of-month is from     * 1 to 31, converting any value beyond the last valid day-of-month to be     * the last valid day-of-month.     */    SMART,    /**     * Style to resolve dates and times leniently.     * <p>     * Using lenient resolution will resolve the values in an appropriate     * lenient manner. Individual fields will interpret this differently.     * <p>     * For example, lenient mode allows the month in the ISO calendar system     * to be outside the range 1 to 12.     * For example, month 15 is treated as being 3 months after month 12.     */    LENIENT;}

public static final DateTimeFormatter ISO_LOCAL_DATE;static {    ISO_LOCAL_DATE = new DateTimeFormatterBuilder()            .appendValue(YEAR, 4, 10, SignStyle.EXCEEDS_PAD)            .appendLiteral('-')            .appendValue(MONTH_OF_YEAR, 2)            .appendLiteral('-')            .appendValue(DAY_OF_MONTH, 2)            .toFormatter(ResolverStyle.STRICT, IsoChronology.INSTANCE);}