Apache Struts 2 Documentation > Home > Guides > Core Developers Guide > Validation > required validator
#editReport()

Description

RequiredFieldValidator checks if the specified field is not null.

Parameters

  • fieldName - field name if plain-validator syntax is used, not needed if field-validator syntax is used

Examples

	   <validators>

        <!-- Plain Validator Syntax -->
        <validator type="required">
            <param name="fieldName">username</param>
            <message>username must not be null</message>
        </validator>


        <!-- Field Validator Syntax -->
        <field name="username">
            <field-validator type="required">
            	   <message>username must not be null</message>
            </field-validator>
        </field>

    </validators>