Hi friends,

Struts provides two files for validation.
1 : validator-rules.xml
2 : validation.xml
with the help of this example, you can do client side validation.
Step 1.
Code of jsp page :

    `<html:form action="/bookSaveAaction" method="post" onsubmit="return validatebookForm(this);"`>

<html:text property="bookId" size="30" maxlength="30"/>
<html:text property="bookName" size="30" maxlength="30"/>

<html:submit>Save</html:submit>

<!-- Start tag of  Validator Javascript Function-->
<html:javascript formName="empForm"/>
<!-- End tag of Validator Javascript Function-->
</html:form>
this tag is used for client side validation.

Step 2.
struts-config.xml is cofiguration file. It is used for action mapping

<action
path="/bookSaveAaction"
type="bookForm"
name="AddressForm"
scope="request"
validate="true"
input="/bookform.jsp">
<forward name="success" path="/success.jsp"/>
</action>

<form-beans>
<form-bean name="bookForm" type="com.roseindia.form.bookForm" />
</form-beans>

Step 3. validator-rules.xml :

The validation definitions available for given application is defined by the validator-rules.xml files. The validator-rules.xml file acts as a template, defining all of the possible Validators that are available to an application.

validator-rules.xml File :

</global>
</form-validation>

    <validator name="required"
                   classname="org.apache.struts.validator.FieldChecks"
                   method="validateRequired"
                   methodParams="java.lang.Object,
                       org.apache.commons.validator.ValidatorAction,
                       org.apache.commons.validator.Field,
                       org.apache.struts.action.ActionMessages,
                       org.apache.commons.validator.Validator,
                       javax.servlet.http.HttpServletRequest"
                   msg="errors.required"/>
   </global>

</form-validation>

Step 4. validation.xml File : The validation.xml file is where you couple the individual Validators defined in the validator-rules.xml to components within your application. validation.xml File

<form-validation>
<formset>
<form name="bookForm">
<field
property="bookId"
depends="required">
<arg key="label.bookId"/>
</field>

<field
property="bookName"
depends="required">
<arg key="label.bookName"/>
</field>
</form>
</formset>
</form-validation>

The bookId and bookName are the required filed of the bookForm . So in the above configuration you can see we add for both bookId and bookName.

You can see depends="required" - "required" property is defind in validator-rules.xml.

In the resource bundle : application_resource.propertis file
label.bookId=bookId
label.bookName=bookName
Error messages used by the Validator errors.required={0} is required.

Based on the validation.xml File configuration . Error in jsp will be : Java Script message.
bookId is required.
bookName is required.

Thanks.