学步园

总得来说,XWork发布了两种类型的验证器,包括我们自定义的.

1. Plain Validators / Non-Field validators
2. FieldValidators

Non-Field Validator Vs Field-Validator

在-validation.xml文件中,我们有两种方式来定义验证器:

1 <validator>

2 <field-validator>

记住以下语法 :

非属性验证器:我们可以在<validator>元素中定义两种验证器,不管是平滑的还是属性验证器.

<validator type="expression> 
    <param name="expression">foo gt bar</param> 
    <message>foo must be great than bar.</message> 
</validator> 

<validator type="required"> 
    <param name="fieldName">bar</param> 
    <message>You must enter a value for bar.</message> 
</validator> 

属性验证器: <field-validator>元素除了继承了 <field> 元素的fieldName属性以外,基本上跟<validator>元素是一样的.定义 在<field-validator>中的属性验证器会自动从父元素<field>的fieldName属性获得fieldName属性值.这样做的原因是方便的将一些验证器进行分组,即可以在一个<field>元素中定义多个<field-validator>元素,这些属性验证器都将验证该属性.如果不这样做的话,在每个单独的<validator>元素中我们都要指定fieldName
属性.

注意: 

 通常在<field>元素中定义属性验证器比在<validator>定义并指定属性名的方式要好,因为这种方式清楚明了.

使用field-validator定义一个属性验证器:

<field name="email_address"> 
    <field-validator type="required"> 
        <message>You cannot leave the email address field empty.</message> 
    </field-validator> 
    <field-validator type="email"> 
        <message>The email address you entered is not valid.</message> 
    </field-validator> 
</field> 

下面两种方式是等价的:

<field name="email_address"> 
    <field-validator type="required"> 
        <message>You cannot leave the email address field empty.</message> 
    </field-validator> 
    <field-validator type="email"> 
        <message>The email address you entered is not valid.</message> 
    </field-validator> 
</field> 
 
<validator type="required"> 
    <param name="fieldName">email_address</param> 
    <message>You cannot leave the email address field empty.</message> 
</validator> 
<validator type="email"> 
    <param name="fieldName">email_address</param> 
    <message>The email address you entered is not valid.</message> 
</validator> 

大家可以自己选择.