What causes "Day of month values must be between 1 and 31" in jeecgboot/JeecgBoot?

Ensure all day-of-month values are integers from 1 to 31.

jeecgboot/JeecgBoot · error · ParseException

Day of month values must be between 1 and 31

Error message

Day of month values must be between 1 and 31

What it means

Thrown by addToSet when a value (or range end) for the DAY_OF_MONTH field is less than 1 or greater than 31, unless the value is ALL_SPEC_INT ('*') or NO_SPEC_INT ('?'). Valid day-of-month values are 1–31.

Source

Thrown at jeecg-boot/jeecg-server-cloud/jeecg-visual/jeecg-cloud-xxljob/src/main/java/com/xxl/job/admin/business/scheduler/cron/CronExpression.java:1000

            throws ParseException {

        TreeSet<Integer> set = getSet(type);

        if (type == SECOND || type == MINUTE) {
            if ((val < 0 || val > 59 || end > 59) && (val != ALL_SPEC_INT)) {
                throw new ParseException(
                        "Minute and Second values must be between 0 and 59",
                        -1);
            }
        } else if (type == HOUR) {
            if ((val < 0 || val > 23 || end > 23) && (val != ALL_SPEC_INT)) {
                throw new ParseException(
                        "Hour values must be between 0 and 23", -1);
            }
        } else if (type == DAY_OF_MONTH) {
            if ((val < 1 || val > 31 || end > 31) && (val != ALL_SPEC_INT)
                    && (val != NO_SPEC_INT)) {
                throw new ParseException(
                        "Day of month values must be between 1 and 31", -1);
            }
        } else if (type == MONTH) {
            if ((val < 1 || val > 12 || end > 12) && (val != ALL_SPEC_INT)) {
                throw new ParseException(
                        "Month values must be between 1 and 12", -1);
            }
        } else if (type == DAY_OF_WEEK) {
            if ((val == 0 || val > 7 || end > 7) && (val != ALL_SPEC_INT)
                    && (val != NO_SPEC_INT)) {
                throw new ParseException(
                        "Day-of-Week values must be between 1 and 7", -1);
            }
        }

        if ((incr == 0 || incr == -1) && val != ALL_SPEC_INT) {
            if (val != -1) {
                set.add(val);

View on GitHub (pinned to 96fb33f5ec)

Solutions

Ensure all day-of-month values are integers from 1 to 31.
Use '?' in the day-of-month field if you are specifying day-of-week instead.
Note that while 29–31 are syntactically valid, they will skip months that have fewer days.

Example fix

// before
String cron = "0 0 0 0 * ?";  // 0 is invalid for day-of-month
// after
String cron = "0 0 0 1 * ?";  // 1st of month

Defensive patterns

Strategy: validation

Validate before calling

// Validate day-of-month field values are 1-31
String domField = fields[3];
for (String token : domField.split(",")) {
    if (token.equals("*") || token.equals("?")) continue;
    String base = token.replaceAll("[LW#].*", "").split("[/\\-]")[0];
    if (!base.isEmpty()) {
        int val = Integer.parseInt(base);
        if (val < 1 || val > 31) throw new IllegalArgumentException("Day-of-month must be 1-31: " + val);
    }
}

Type guard

boolean isValidDayOfMonth(String field) {
    for (String token : field.split(",")) {
        if (token.equals("*") || token.equals("?")) continue;
        String base = token.replaceAll("[LW#].*", "").split("[/\\-]")[0];
        try {
            int val = Integer.parseInt(base);
            if (val < 1 || val > 31) return false;
        } catch (NumberFormatException e) { return false; }
    }
    return true;
}

Try / catch

try {
    CronExpression cron = new CronExpression(expr);
} catch (ParseException e) {
    if (e.getMessage().contains("Day of month values must be between 1 and 31")) {
        // fix the day-of-month field value
    }
    throw e;
}

Prevention

Day-of-month values start at 1, not 0.
Values 29–31 are syntactically valid but will be skipped in shorter months.
Use '?' for day-of-month when scheduling by day-of-week.

When it happens

Trigger: A cron expression with a day-of-month field containing a value like 0, 32, or -1 — e.g., day-of-month field '32', '0', or range '1-35'.

Common situations: Developer uses 0 as a day (days start at 1); uses 32 or higher; range endpoint exceeds 31; confusion with 0-based indexing from other systems.

Related errors

AI-assisted analysis of jeecgboot/JeecgBoot@96fb33f5ec (2026-08-14). Data as JSON: /api/errors/7eaf9a139d6c4fb0. Report an issue: GitHub.