jsf2 自定义 标签校验器

jsf2.0 下，想自定义一个校验器，能接受页面送来的参数，但是百度看了很多自定义校验器，都是仅仅是继承 javax.faces.validator， 实现校验功能，这样无法接收页面传来的参数，谷歌了一下，也没找到例子，想了一下， 既然jsf 自定义的标签可以接收参数，仿照它写一个，肯定也可以，于是下载了myfaces 源码（本人用的是myfaces2.0），看他是怎么写的。就拿javax.faces.validator.LengthValidator 来说吧。 为了实现校验功能 ，定义了LengthValidator 类，继承了Validator, PartialStateHolder  ，其中Validator 是为了实现校验功能，

PartialStateHolder 是为了保存页面状态， 然后还定义了一个 继承GenericMinMaxValidatorTag 的ValidateLengthTag ，用于，页面标签

LengthValidator 

package javax.faces.validator;

import javax.faces.component.PartialStateHolder;
import javax.faces.component.StateHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;

import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFJspProperty;
import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFProperty;
import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFValidator;

@JSFValidator(
    name="f:validateLength",
    bodyContent="empty",
    tagClass="org.apache.myfaces.taglib.core.ValidateLengthTag")
@JSFJspProperty(
    name="binding", 
    returnType = "javax.faces.validator.LengthValidator",
    longDesc = "A ValueExpression that evaluates to a LengthValidator.")
public class LengthValidator
        implements Validator, PartialStateHolder
{

ValidateLengthTag 

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.myfaces.taglib.core;

import org.apache.myfaces.convert.ConverterUtils;

import javax.faces.validator.LengthValidator;
import javax.faces.validator.Validator;
import javax.servlet.jsp.JspException;

/**
 * @author Thomas Spiegl (latest modification by $Author: bommel $)
 * @author Manfred Geiler
 * @version $Revision: 1187700 $ $Date: 2011-10-22 07:19:37 -0500 (Sat, 22 Oct 2011) $
 */
public class ValidateLengthTag extends GenericMinMaxValidatorTag<Integer>
{
    private static final long serialVersionUID = 4858632671998693059L;

    private static final String VALIDATOR_ID = "javax.faces.Length";

定义了这2类后，myface 还在/src/META-INF 下standard-faces-config.xml 与myfaces-metadata.xml 注册了这个组件

myfaces-metadata.xml 

<validator>
    <modelId>myfaces-api</modelId>
    <className>javax.faces.validator.LengthValidator</className>
    <sourceClassName>javax.faces.validator.LengthValidator</sourceClassName>
    <name>f:validateLength</name>
    <validatorId>javax.faces.Length</validatorId>
    <bodyContent>empty</bodyContent>
    <tagClass>org.apache.myfaces.taglib.core.ValidateLengthTag</tagClass>
    <generatedTagClass>true</generatedTagClass>
    <desc>Creates a validator and associateds it with the nearest parent
UIComponent</desc>
    <longDesc>
<![CDATA[
Creates a validator and associateds it with the nearest parent
UIComponent.  When invoked, the validator ensures that values are
valid strings with a length that lies within the minimum and maximum
values specified.

Commonly associated with a h:inputText entity.

Unless otherwise specified, all attributes accept static values or EL expressions.

see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>
]]>
    </longDesc>
    <property>
      <name>maximum</name>
      <className>int</className>
      <desc>The largest value that should be considered valid</desc>
      <longDesc>The largest value that should be considered valid.</longDesc>
      <deferredValueType>java.lang.Integer</deferredValueType>
    </property>
    <property>
      <name>minimum</name>
      <className>int</className>
      <desc>The smallest value that should be considered valid</desc>
      <longDesc>The smallest value that should be considered valid.</longDesc>
      <deferredValueType>java.lang.Integer</deferredValueType>
    </property>
    <property>
      <name>disabled</name>
      <className>java.lang.Boolean</className>
      <desc>no description</desc>
      <faceletsOnly>true</faceletsOnly>
    </property>
    <property>
      <name>for</name>
      <className>java.lang.String</className>
      <desc>no description</desc>
      <faceletsOnly>true</faceletsOnly>
    </property>
    <property>
      <name>binding</name>
      <className>javax.faces.validator.LengthValidator</className>
      <desc>A ValueExpression that evaluates to a LengthValidator.</desc>
      <longDesc>A ValueExpression that evaluates to a LengthValidator.</longDesc>
      <generated>false</generated>
    </property>
  </validator>

standard-faces-config.xml 下

     <validator-id>javax.faces.Length</validator-id>
    <validator-class>javax.faces.validator.LengthValidator</validator-class>

最后，myfaces还在CoreLibrary 中添加了这个校验器

package org.apache.myfaces.view.facelets.tag.jsf.core;

import javax.faces.component.UIParameter;
import javax.faces.component.UISelectItem;
import javax.faces.component.UISelectItems;
import javax.faces.component.UIViewParameter;
import javax.faces.convert.DateTimeConverter;
import javax.faces.convert.NumberConverter;
import javax.faces.validator.BeanValidator;
import javax.faces.validator.DoubleRangeValidator;
import javax.faces.validator.LengthValidator;
import javax.faces.validator.LengthValidatorXZM;
import javax.faces.validator.LongRangeValidator;
import javax.faces.validator.RegexValidator;
import javax.faces.validator.RequiredValidator;

import org.apache.myfaces.view.facelets.tag.AbstractTagLibrary;

/**
 * For Tag details, see JSF Core <a target="_new"
 * href="http://java.sun.com/j2ee/javaserverfaces/1.1_01/docs/tlddocs/f/tld-summary.html">taglib documentation</a>.
 *
 * @author Jacob Hookom
 * @version $Id: CoreLibrary.java 1187700 2011-10-22 12:19:37Z bommel $
 */
public final class CoreLibrary extends AbstractTagLibrary{   /<pre code_snippet_id="409043" snippet_file_name="blog_20140628_6_9206090" name="code" class="java"><span style="font-family: Arial, Helvetica, sans-serif;">  this.addValidator("validateLength", LengthValidator.VALIDATOR_ID);</span>

其实我们在 myfaces-metadata.xml ，myfaces-metadata.xml  中定义自己的校验器 然后在CoreLibrary 中注册