jeecgboot/JeecgBoot · error · ParseException

Month values must be between 1 and 12

Error message

Month values must be between 1 and 12

What it means

Thrown by addToSet when a value (or range end) for the MONTH field is less than 1 or greater than 12, unless the value equals ALL_SPEC_INT ('*'). Valid month values are 1–12 (January=1 through December=12).

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:1005

            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);
            } else {
                set.add(NO_SPEC);
            }

            return;

View on GitHub (pinned to 96fb33f5ec)

Solutions

1. Ensure all month values are integers from 1 to 12 (1=January, 12=December).
2. If converting from Java Calendar months (0-based), add 1 before constructing the cron string.
3. If converting from JavaScript Date.getMonth() (0-based), add 1.

Example fix

// before
// month field uses 0 (Java Calendar January)
String cron = "0 0 0 1 0 ?";  // 0 is invalid
// after
String cron = "0 0 0 1 1 ?";  // January (1-based)

// Validate month field values are 1-12
String monthField = fields[4];
for (String token : monthField.split(",")) {
    if (token.equals("*") || token.equals("?")) continue;
    String base = token.split("[/\\-]")[0];
    int val = Integer.parseInt(base);
    if (val < 1 || val > 12) throw new IllegalArgumentException("Month must be 1-12: " + val);
}

boolean isValidMonth(String field) {
    for (String token : field.split(",")) {
        if (token.equals("*") || token.equals("?")) continue;
        try {
            for (String part : token.split("[/\\-]")) {
                int val = Integer.parseInt(part);
                if (val < 1 || val > 12) return false;
            }
        } catch (NumberFormatException e) { return false; }
    }
    return true;
}

try {
    CronExpression cron = new CronExpression(expr);
} catch (ParseException e) {
    if (e.getMessage().contains("Month values must be between 1 and 12")) {
        // fix the month field value (1=January)
    }
    throw e;
}

When it happens

Trigger: A cron expression with a month field containing a value like 0, 13, or -1 — e.g., month field '13', '0', or range '1-13'. Note: some cron implementations also accept names (JAN–DEC) but this numeric check applies to parsed integer values.

Common situations: Developer uses 0-based month numbering (0=January); uses 13 or higher; off-by-one from JavaScript Date or Java Calendar (both 0-based); dynamic value injection without bounds checking.

Related errors

• Day-of-Week values must be between 1 and 7
• 'L' option is not valid here. (pos=${i})
• 'W' option is not valid here. (pos=${i})
• The 'W' option does not make sense with values larger than 3
• '#' option is not valid here. (pos=${i})

AI-assisted analysis of jeecgboot/JeecgBoot@96fb33f5ec (2026-08-14). Data as JSON: /api/errors/f5c011ed1ff0b3aa. Report an issue: GitHub.