Shale Validate 机制初探

Validation Introduction

JavaServer Faces 1.x does not explicitly support client-side validation and only provides a minimal set of server-side validators. On the other hand, Apache Commons Validator supports both client- and server-side validators and comes with the following useful validators:

• Credit Card
• Date
• Email
• Generic
• ISBN
• URL

All of the preceding validators can be executed either on the client or the server, or both. Shale integrates JavaServer Faces and the Commons Validator.
For example:

   

Server Validate Demo:

<h:inputText     id="amount"
                   value="#{validate$test.amount}"
                    size="7">

        <f:convertNumber
       minFractionDigits="2"/>

        <val:commonsValidator
                    type="floatRange"
                     min="10"
                     max="1000"
                     arg="#{messages['validate.test.amount']}"
                  server="true"
                  client="false"/>

     </h:inputText>

Client side Validate demo:

<h:inputText     id="date"
                     value="#{validate$test.expirationDate}">

         <f:convertDateTime
                    pattern="MM/dd/yyyy"/>

           <val:commonsValidator
                       type="required"
                       arg="#{messages['prompt.expirationDate']}"
                    server="false"
                    client="true"/>

         <val:commonsValidator
                      type="date"
         datePatternStrict="MM/dd/yyyy"
                   message="#{messages['validate.test.bad.expiration.date']}"
                       arg="#{messages['prompt.expirationDate']}"
                    server="false"
                    client="true"/>

      </h:inputText>

 

Services Provided

Shale provides three JSP tags that let you use the Commons Validator: val:commonsValidator, val:validatorVar, and val:validatorScript. The first two lets you attach a commons validator to a JSF input component and the third generates JavaScript validation code for validating each JSF component that has one or more Commons validators in a particular form. You can attach as many Commons validators to a single JSF input component as you wish.

Using Commons Validator Integration

Here's what you need to do to use Shale validation:

• Add an onsubmit attribute to your h:form tag that calls the JavaScript validation function generated by val:validatorScript.
• Add Commons validators to JSF input components with val:commonsValidator and, optionally, val:validatorVar.
• Add an val:validatorScript tag at the end of the h:form tag's body.

Here's an example:

<%@ taglib uri="http://shale.apache.org/core" prefix="val" %>
...
<h:form onsubmit="return validateForm(this);">

    <h:inputText id="creditCardNumber"
               size="16"
              value="#{userContext.creditCardNumber}">

        <val:commonsValidator type="required"
                             arg="#{msgs.creditCardNumberPrompt}"
                          server="true"
                          client="true"/>

        <val:commonsValidator type="mask"
                             arg="#{msgs.creditCardNumberPrompt}"
                          server="true"
                          client="true">
            <val:validatorVar name="mask" value="[4-6].*"/>
        </val:commonsValidator>

        <val:commonsValidator type="creditCard"
                             arg="#{msgs.creditCardNumberPrompt}"
                          server="true"/>
    </h:inputText>

    <h:message for="creditCardNumber" styleClass="errors"/>

    <val:validatorScript functionName="validateForm"/>
</h:form>

   In the preceding example, we've attached three Commons validators to a single JSF input component. To pass validation, the field must have a value that starts with a number between 4 and 6 inclusive and that value must be a valid credit card number as verified by the Luhn algorithm. Two of the validations are performed on both client and server and one is performed on the server only.

  Note: At the present time, you have the option to forego server-side validation, which is considered very bad practice. Users can turn off JavaScript, so you should always backup client-side validation with server-side validation. In the future, Shale may enforce server-side validation if it's not explicitly specified.