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Apache Struts 2 Documentation
stringlength validator
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# Description

StringLengthFieldValidator checks that a String field is of a certain length. If the "minLength" parameter is specified, it will make sure that the String has at least that many characters. If the "maxLength" parameter is specified, it will make sure that the String has at most that many characters. The "trim" parameter determines whether it will {@link String#trim() trim} the String before performing the length check. If unspecified, the String will be trimmed.

# Parameters

- fieldName - The field name this validator is validating. Required if using Plain-Validator Syntax otherwise not required
- maxLength - Integer. The max length of the field value. Default ignore.
- minLength - Integer. The min length of the field value. Default ignore.
- trim - (Optional) Boolean, default true. Trim the field value before evaluating its min/max length. Default true.
- maxLengthExpression - (Optional) String. Defines the max length param as an OGNL expression
- minLengthExpression - (Optional) String. Defines the min length param as an OGNL expression
- trimExpression - (Optional) String. Defines th trim param as an OGNL expression

Warning

Do not use ${minLengthExpression}, ${maxLengthExpression} and ${trimExpression} as an expression as this will turn into infinitive loop!

# Examples