Shale Validate 机制初探

最新推荐文章于 2025-08-14 14:23:15 发布

最新推荐文章于 2025-08-14 14:23:15 发布 · 134 阅读

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本文介绍如何在JavaServer Faces (JSF)中使用Apache Shale集成Commons Validator进行客户端和服务端验证。通过示例展示了如何为JSF输入组件添加多种验证器，并确保表单提交前的数据准确性。

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.