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# Using Field Validators

## Description

The followings show a simple example using Struts’ Field Validators

### Step 1

Create the jsp page

    <h3>All Field Errors Will Appear Here</h3>
    <s:fielderror/>
    <hr/>

    <h3>Field Error due to 'Required String Validator Field' Will Appear Here</h3>
    <s:fielderror>
        <s:param value="%{'requiredStringValidatorField'}"/>
    </s:fielderror>
    <hr/>

    <h3>Field Error due to 'String Length Validator Field' Will Appear Here</h3>
    <s:fielderror>
        <s:param>stringLengthValidatorField</s:param>
    </s:fielderror>
    <hr/>

    <s:form action="submitFieldValidatorsExamples" namespace="/validation" method="POST" theme="xhtml">
        <s:textfield label="Required Validator Field" name="requiredValidatorField"/>
        <s:textfield label="Required String Validator Field" name="requiredStringValidatorField"/>
        <s:textfield label="Integer Validator Field" name="integerValidatorField"/>
        <s:textfield label="Date Validator Field" name="dateValidatorField"/>
        <s:textfield label="Email Validator Field" name="emailValidatorField"/>
        <s:textfield label="URL Validator Field" name="urlValidatorField"/>
        <s:textfield label="String Length Validator Field" name="stringLengthValidatorField"/>
        <s:textfield label="Regex Validator Field" name="regexValidatorField"/>
        <s:textfield label="Field Expression Validator Field" name="fieldExpressionValidatorField"/>
        <s:submit label="Submit" cssClass="btn btn-primary"/>
    </s:form>

### Step 2

Create the action class

    public class FieldValidatorsExampleAction extends AbstractValidationActionSupport {

        private String requiredValidatorField = null;
        private String requiredStringValidatorField = null;
        private Integer integerValidatorField = null;
        private Date dateValidatorField = null;
        private String emailValidatorField = null;
        private String urlValidatorField = null;
        private String stringLengthValidatorField = null;
        private String regexValidatorField = null;
        private String fieldExpressionValidatorField = null;

        public Date getDateValidatorField() {
            return dateValidatorField;
        }

        public void setDateValidatorField(Date dateValidatorField) {
            this.dateValidatorField = dateValidatorField;
        }

        public String getEmailValidatorField() {
            return emailValidatorField;
        }

        public void setEmailValidatorField(String emailValidatorField) {
            this.emailValidatorField = emailValidatorField;
        }

        public Integer getIntegerValidatorField() {
            return integerValidatorField;
        }

        public void setIntegerValidatorField(Integer integerValidatorField) {
            this.integerValidatorField = integerValidatorField;
        }

        public String getRegexValidatorField() {
            return regexValidatorField;
        }

        public void setRegexValidatorField(String regexValidatorField) {
            this.regexValidatorField = regexValidatorField;
        }

        public String getRequiredStringValidatorField() {
            return requiredStringValidatorField;
        }

        public void setRequiredStringValidatorField(String requiredStringValidatorField) {
            this.requiredStringValidatorField = requiredStringValidatorField;
        }

        public String getRequiredValidatorField() {
            return requiredValidatorField;
        }

        public void setRequiredValidatorField(String requiredValidatorField) {
            this.requiredValidatorField = requiredValidatorField;
        }

        public String getStringLengthValidatorField() {
            return stringLengthValidatorField;
        }

        public void setStringLengthValidatorField(String stringLengthValidatorField) {
            this.stringLengthValidatorField = stringLengthValidatorField;
        }

        public String getFieldExpressionValidatorField() {
            return fieldExpressionValidatorField;
        }

        public void setFieldExpressionValidatorField(
                String fieldExpressionValidatorField) {
            this.fieldExpressionValidatorField = fieldExpressionValidatorField;
        }

        public String getUrlValidatorField() {
            return urlValidatorField;
        }

        public void setUrlValidatorField(String urlValidatorField) {
            this.urlValidatorField = urlValidatorField;
        }
    }

### Step 3

Create the `validator.xml`.

    <validators>
        <field name="requiredValidatorField">
            <field-validator type="required">
                <message><![CDATA[ required ]]></message>
            </field-validator>
        </field>
        <field name="requiredStringValidatorField">
            <field-validator type="requiredstring">
                <param name="trim">true</param>
                <message><![CDATA[ required and must be string ]]></message>
            </field-validator>
        </field>
        <field name="integerValidatorField">
            <field-validator type="int">
                <param name="min">1</param>
                <param name="max">10</param>
                <message><![CDATA[ must be integer min 1 max 10 if supplied ]]></message>
            </field-validator>
        </field>
        <field name="dateValidatorField">
            <field-validator type="date">
                <param name="min">01/01/1990</param>
                <param name="max">01/01/2000</param>
                <message><![CDATA[ must be a min 01-01-1990 max 01-01-2000 if supplied ]]></message>
            </field-validator>
        </field>
        <field name="emailValidatorField">
            <field-validator type="email">
                <message><![CDATA[ must be a valid email if supplied ]]></message>
            </field-validator>
        </field>
        <field name="urlValidatorField">
            <field-validator type="url">
                <message><![CDATA[ must be a valid url if supplied ]]></message>
            </field-validator>
        </field>
        <field name="stringLengthValidatorField">
            <field-validator type="stringlength">
                <param name="maxLength">4</param>
                <param name="minLength">2</param>
                <param name="trim">true</param>
                <message><![CDATA[ must be a String of a specific greater than 1 less than 5 if specified ]]></message>
            </field-validator>
        </field>
        <field name="regexValidatorField">
            <field-validator type="regex">
                <param name="regex"><![CDATA[ [^<>]+ ]]></param>
                <message><![CDATA[ regexValidatorField must match a regexp (.*.txt) if specified ]]></message>
            </field-validator>
        </field>
        <field name="fieldExpressionValidatorField">
            <field-validator type="fieldexpression">
                <param name="expression">(fieldExpressionValidatorField == requiredValidatorField)</param>
                <message><![CDATA[ must be the same as the Required Validator Field if specified ]]></message>
            </field-validator>
        </field>
    </validators>