struts2------自定义校验器

        自定义验证器必须实现 Validator 接口,为了简化校验器的开发，框架提供了两个抽象类ValidatorSupport 和FieldValidatorSupport。其中ValidatorSupport【用于定义非字段优先的校验器】 和 FieldValidatorSupport【用于字段优先的校验器】 实现了 Validator 接口，同时提供了用于实现数据校验的通用方法。

 

实现用户名称的唯一性校验---自定义校验器

1. 继承FieldValidatorSupport实现字段有限的校验器

public class UniqueNameValidator extends FieldValidatorSupport {       @Override     public void validate(Object object) throws ValidationException {        // 覆盖定义validate方法实现数据校验逻辑        String name = this.getFieldName();// 获取输入域的名称的name值        String value = this.getFieldValue(name, object).toString();// 获取用户输入的数据，已经完成了数据类型转换，可以直接获取到转换后的结果        // 具体的验证处理逻辑        if (value != null && value.trim().length() > 0) {            IUserServ userv = ServiceFactory.getUserService();            boolean bb = userv.existsName(value);            if(bb){//验证没有通过，用户名称已经存在，添加配置的默认报错信息               this.addFieldError(name, this.getDefaultMessage());            }        }     } }

如果不是很通用的校验，比较建议使用validateXxxx的方法实现，不建议自定义校验器

如果使用了自定义校验方法validateXXX和校验框架两种方法，请注意没有互斥,两个都会被执行

2、注册校验器

将struts2-core.jar中/com/opensymphony/xwork2/validator/validators/default.xml拷贝到src根路径下，并更名为validators.xml，然后添加自定义校验器的说明

xml version="1.0" encoding="UTF-8"?> DOCTYPE validators PUBLIC         "-//Apache Struts//XWork Validator Definition 1.0//EN"         "http://struts.apache.org/dtds/xwork-validator-definition-1.0.dtd"> <validators>     <validator name="required"        class="com.opensymphony.xwork2.validator.validators.RequiredFieldValidator" />     <validator name="requiredstring"        class="com.opensymphony.xwork2.validator.validators.RequiredStringValidator" />     <validator name="int"        class="com.opensymphony.xwork2.validator.validators.IntRangeFieldValidator" />     <validator name="long"        class="com.opensymphony.xwork2.validator.validators.LongRangeFieldValidator" />     <validator name="short"        class="com.opensymphony.xwork2.validator.validators.ShortRangeFieldValidator" />     <validator name="double"        class="com.opensymphony.xwork2.validator.validators.DoubleRangeFieldValidator" />     <validator name="date"        class="com.opensymphony.xwork2.validator.validators.DateRangeFieldValidator" />     <validator name="expression"        class="com.opensymphony.xwork2.validator.validators.ExpressionValidator" />     <validator name="fieldexpression"        class="com.opensymphony.xwork2.validator.validators.FieldExpressionValidator" />     <validator name="email"        class="com.opensymphony.xwork2.validator.validators.EmailValidator" />     <validator name="creditcard"        class="com.opensymphony.xwork2.validator.validators.CreditCardValidator" />     <validator name="url"        class="com.opensymphony.xwork2.validator.validators.URLValidator" />     <validator name="visitor"        class="com.opensymphony.xwork2.validator.validators.VisitorFieldValidator" />     <validator name="conversion"         class="com.opensymphony.xwork2.validator.validators.ConversionErrorFieldValidator" />     <validator name="stringlength"        class="com.opensymphony.xwork2.validator.validators.StringLengthFieldValidator" />     <validator name="regex"        class="com.opensymphony.xwork2.validator.validators.RegexFieldValidator" />     <validator name="conditionalvisitor"         class="com.opensymphony.xwork2.validator.validators.ConditionalVisitorFieldValidator" />     "uniqueName"        class="com.yao.action.validator.UniqueNameValidator" /> validators>

3、在校验规则说明文件中引用自定义的校验器uniqueName

xml version="1.0" encoding="UTF-8"?> DOCTYPE validators PUBLIC         "-//Apache Struts//XWork Validator 1.0.3//EN"         "http://struts.apache.org/dtds/xwork-validator-1.0.3.dtd"> <validators>     <field name="username">        <field-validator type="requiredstring" short-circuit="true">            <message>用户名称必须填写!message>        field-validator>        <field-validator type="stringlength" short-circuit="true">            <param name="minLength">6param>            <param name="maxLength">20param>            <message>用户名称应该在6到20个字符之间!message>        field-validator>        "uniqueName">            用户名称已经被占用!            field> validators>