jsf验证器创建

创建一个验证器，验证两个日期的前后关系：有两个输入框：Form，To。输入To的时间不能比Form的时间晚/迟
步骤一：
创建验证类：com.expense.valcus.LaterThanValidator
 

package com.expense.valcus;
 

import java.text.MessageFormat;
import java.io.Serializable;
import java.util.Date;
import java.util.Locale;
import java.util.ResourceBundle;
import javax.faces.application.Application;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.ValueHolder;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;
 

/**
* This class is a JSF Validator that validates that the java.util.Date
* value of the component it's attached to is later than the
* java.util.Date value of another component.
*
* @author Hans Bergsten, Gefion Software <hans@gefionsoftware.com>
* @version 1.0
*/
public class LaterThanValidator implements Validator, Serializable {
   /**
        *
        */
       private static final long serialVersionUID = 1170859790387692325L;
       private String peerId;
 

   /**
    * Sets the ID for the peer component the main component's
    * value is compared to. It must be a format that can be
    * used with the javax.faces.component.UIComponent findComponent()
    * method.
    */
   public void setPeerId(String peerId) {
       this.peerId = peerId;
   }
 

   /**
    * Compares the provided value to the value of the peer component,
    * and throws a ValidatorException with an appropriate FacesMessage
    * if the provided value doesn't represent a later date or if
    * there are problems accessing the peer component value.
    */
   public void validate(FacesContext context, UIComponent component,
                      Object value) throws ValidatorException {
 

       Application application = context.getApplication();
 

       /* Note! This validator requires an application bundle
        * that holds the messages. For validators, or other
        * components, that should be usable in any application,
        * bundling a default bundle and use it if the message
        * isn't available in the application bundle is a nicer
        * approach.
        */
       String messageBundleName = application.getMessageBundle();
       Locale locale = context.getViewRoot().getLocale();
       ResourceBundle rb =
           ResourceBundle.getBundle(messageBundleName, locale);
 

       UIComponent peerComponent = component.findComponent(peerId);
       if (peerComponent == null) {
           String msg = rb.getString("peer_not_found");
           FacesMessage facesMsg =
              new FacesMessage(FacesMessage.SEVERITY_FATAL, msg, msg);
           throw new ValidatorException(facesMsg);
       }
     
       ValueHolder peer = null;
       try {
           peer = (ValueHolder) peerComponent;
       }
       catch (ClassCastException e) {
           String msg = rb.getString("invalid_component");
           FacesMessage facesMsg =
              new FacesMessage(FacesMessage.SEVERITY_FATAL, msg, msg);
           throw new ValidatorException(facesMsg);
       }
       if (peer instanceof EditableValueHolder &&
           !((EditableValueHolder) peer).isValid()) {
           // No point in validating against an invalid value
           return;
       }
      
       Object peerValue = peer.getValue();
       if (!(peerValue instanceof Date)) {
           String msg = rb.getString("invalid_peer");
           FacesMessage facesMsg =
              new FacesMessage(FacesMessage.SEVERITY_FATAL, msg, msg);
           throw new ValidatorException(facesMsg);
       }
     
       if (!(value instanceof Date) ||
           !((Date) value).after((Date) peerValue)) {
           String msg = rb.getString("not_later");
           String detailMsgPattern = rb.getString("not_later_detail");
           Object[] params =
               {formatDate((Date) peerValue, context, component)};
           String detailMsg =
              MessageFormat.format(detailMsgPattern, params);
           FacesMessage facesMsg =
              new FacesMessage(FacesMessage.SEVERITY_ERROR, msg, detailMsg);
           throw new ValidatorException(facesMsg);
       }
   }
 

   /**
    * Returns the provided Date formatted with the converter attached
    * to the component, if any, or with toString() otherwise.
    */
   private String formatDate(Date date, FacesContext context,
       UIComponent component) {
       Converter converter = ((ValueHolder) component).getConverter();
       if (converter != null) {
           return converter.getAsString(context, component, date);
       }
       return date.toString();
   }
}
 

 

步骤二：在WEB-INF/faces-config.xml文件里面注册自定义验证器
 

<face-config>
   ......
 

       <validator>
              <validator-id>
                     com.expense.validator.ID
              </validator-id>
              <validator-class>
                     com.expense.valcus.LaterThanValidator
              </validator-class>
              <property>
                     <property-name>peerId</property-name>
                     <property-class>java.lang.String</property-class>
              </property>
       </validator>
 

......
</face-config>
 

步骤三：开发自定义的动作组件：
1>首先创建WEB-INF/tagc.tld
 

 

 

 

<taglib>
 

 <tlib-version>1.0</tlib-version>
 <jsp-version>1.2</jsp-version>
 <short-name>my</short-name>
 <uri>http://expense.com/myjsftag</uri>
 <description>
   The core JavaServer Faces custom actions that are independent of
   any particular RenderKit.
 </description>
 

 <tag>
      <name>validatelater</name>
      <tag-class>com.expense.valcus.ValidateLaterThanTag</tag-class>
      <body-content>empty</body-content>
      <attribute>
             <name>than</name>
             <required>true</required>
             <rtexprvalue>false</rtexprvalue>
      </attribute>
 </tag>
</taglib>
2>创建动作标记类：com.expense.valcus.ValidateLaterThanTag
package com.expense.valcus;
 

import javax.faces.application.Application;
import javax.faces.context.FacesContext;
import javax.faces.validator.Validator;
import javax.faces.webapp.ValidatorTag;
 

/**
* This class is a tag handler that creates and configures a
* "com.mycompany.jsf.validator.LATER_THAN" validator.
*
* @author Hans Bergsten, Gefion Software <hans@gefionsoftware.com>
* @version 1.0
*/
public class ValidateLaterThanTag extends ValidatorTag {
   /**
        *
        */
       private static final long serialVersionUID = 910680118767808902L;
       private String than;
 

   /**
    * Sets the client ID for the component holding the value to
    * compare the value of the component with this validator to.
    */
   public void setThan(String peerId) {
       this.than = peerId;
   }
 

   /**
    * Returns a new instance of the validator registered under the name
    * "com.mycompany.jsf.validator.LATER_THAN", configured with the
    * "than" property value.
    */
   protected Validator createValidator() {
       Application application =
           FacesContext.getCurrentInstance().getApplication();
       LaterThanValidator validator = (LaterThanValidator)
           application.createValidator("com.expense.validator.ID");
       validator.setPeerId(than);
       return validator;
   }
}
 

 

步骤四：在jsp网页里面使用：
1>
创建jsp网页：
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%@ include file="tags.jsp"%>
<% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>
 

 

 

 

   <base href="%3C%=basePath%%3E">
 
<title>My JSP 'filterArea.jsp' starting page</title>  
 
       <meta equiv="pragma" content="no-cache">
       <meta equiv="cache-control" content="no-cache">
       <meta equiv="expires" content="0">  
       <meta equiv="keywords" content="keyword1,keyword2,keyword3">
       <meta equiv="description" content="This is my page">
       <!--        <link rel="stylesheet" type="text/css" href="styles.css"><br />   -->
 

 

 

 

 <f:view>
      <h:form>
             From:
 

             <h:inputtext id="from" size="8" required="true" value="#{valCus.from }">
             <f:convertdatetime datestyle="short">
             </f:convertdatetime>
             <h:message for="from"></h:message>
            
To:
 

             <h:inputtext id="to" size="8" required="true" value="#{valCus.to }">
             <f:convertdatetime datestyle="short">
             <my:validatelater than="from">
             </my:validatelater>
             <h:message for="to">
            
 

             <h:commandbutton value="Filter"></h:commandbutton>
      </h:message>
 </f:convertdatetime>
 

 

 

其中<%@ include file="tags.jsp"%>中的tags.jsp如下：
<%@ page language="java" pageEncoding="GB18030"%>
<%@ page contentType="text/html" %>
<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>
<%@ taglib uri="http://expense.com/myjsftag" prefix="my" %>
 

2>创建实体类：com.expense.valcus。ValCus
package com.expense.valcus;
 

import java.util.Date;
 

public class ValCus {
 

       private Date from;
       private Date to;
       public Date getFrom() {
              if(from == null)
                     return new Date();
              return from;
       }
       public void setFrom(Date from) {
              this.from = from;
       }
       public Date getTo() {
              if(to == null)
                     return new Date();
              return to;
       }
       public void setTo(Date to) {
              this.to = to;
       }
}
 

 

最后:完整的faces-config.xml文件如下：
<faces-config>
       <validator>
              <validator-id>
                     com.expense.validator.ID
              </validator-id>
              <validator-class>
                     com.expense.valcus.LaterThanValidator
              </validator-class>
              <property>
                     <property-name>peerId</property-name>
                     <property-class>java.lang.String</property-class>
              </property>
       </validator>
       <managed-bean>
              <managed-bean-name>valCus</managed-bean-name>
              <managed-bean-class>
                     com.expense.valcus.ValCus
              </managed-bean-class>
              <managed-bean-scope>session</managed-bean-scope>
 

       </managed-bean>
</faces-config>