STRUTS 2 CUSTOM VALIDATIONS

Custom Validations :(Prepared by Appaji,senior software engineer)

Requirements: Custom validations are required if default validations are not sufficient to fulfill the needs. Struts 2 allows the use of Custom validators through the @CustomValidator annotation Framework used:struts2 Approach: 1. In existing struts project add the fallowing code in jsp <s:actionerror/> <s:fielderror/> <s:textfield name="price" size="20" label="price"/>

2. Add CustomValidator to setPrice() method.

The @CustomValidator annotation takes two parameters, type and message

• type: Refers to the "name" given to the validator in the validators.xml file. message: Message to be displayed when this validator fails. the type attribute of the @CustomValidator Annotation must match the name of the validator as defined in the validators.xml file private Integer price=null; public Integer getPrice() { return price; } @ Required() @ CustomValidator(type="pricefield") public void setPrice(Integer price) { this.price = price; } 3.Declare the new custom validator in the validators.xml file. The validators.xml file must be in the classpath of the application

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE validators PUBLIC

"-//OpenSymphony Group//XWork Validator Config 1.0//EN" "http://www.opensymphony.com/xwork/xwork-validator-config-1.0.dtd"> <validators>

<validator name="pricefield" class="com.gdas.gdas.web.action.PriceValidator"/> </validators> note:dont include existing validators inside validators.xml 4. Create PriceValidator by extending the FieldValidatorSupport class import org.apache.struts.action.ActionErrors; import org.apache.struts.action.ActionMessages; import org.apache.struts2.components.ActionError; import com.opensymphony.xwork2.validator.ValidationException; import com.opensymphony.xwork2.validator.Validator; import com.opensymphony.xwork2.validator.validators.FieldValidatorSupport;

public class PriceValidator extends FieldValidatorSupport {

@Override public void validate(Object object) throws ValidationException { String fieldName = getFieldName(); Object value = this.getFieldValue(fieldName, object); System.out.println("fieldName-->"+fieldName+"value-->"+value);

if(value==null) {

setDefaultMessage("You enter null");

addFieldError(getDefaultMessage(), object);

return ;

}

if((Integer)value==111) {

setDefaultMessage("You enter 111");

addFieldError(getDefaultMessage(), object);

return ;

}

try {

Integer price=(Integer)value;

return;

}catch(Exception e) {

addFieldError(fieldName, object);

}

}

}

The addFieldError method is used add any failed validations to the list of errors to be displayed. The getFieldName and getFieldValue methods are implemented in the superclasses to retrieve the field name and field value for the field beign validated. The custom validator may extend the FieldValidatorSupport or the ValidatorSupport classes. Let me know if you have any queries on this, Regards , Appaji,

appaji_it@yahoo.com