jcaptcha集群时验证码不能验证的问题

package com.dzf.core.security.jcaptcha;
 
import java.util.Collection;
import java.util.Locale;
 
import javax.servlet.http.HttpServletRequest;
 
import com.octo.captcha.Captcha;
import com.octo.captcha.service.CaptchaServiceException;
 
public interface CaptchaStore{
    public abstract boolean hasCaptcha(String paramString);
 
    /** @deprecated */
    public abstract void storeCaptcha(String paramString, Captcha paramCaptcha)
      throws CaptchaServiceException;
 
    public abstract void storeCaptcha(String paramString, Captcha paramCaptcha, Locale paramLocale)
      throws CaptchaServiceException;
 
    public abstract boolean removeCaptcha(String paramString);
 
    public abstract Captcha getCaptcha(String paramString)
      throws CaptchaServiceException;
 
    public abstract Locale getLocale(String paramString)
      throws CaptchaServiceException;
 
    public abstract int getSize();
 
    public abstract Collection getKeys();
 
    public abstract void empty();
 
    public abstract void initAndStart();
 
    public abstract void cleanAndShutdown();
    
  public abstract void setRequest(HttpServletRequest request);
  
  public abstract HttpServletRequest getRequest();
}

/*
 * JCaptcha, the open source java framework for captcha definition and integration
 * Copyright (c)  2007 jcaptcha.net. All Rights Reserved.
 * See the LICENSE.txt file distributed with this package.
 */
 
package com.dzf.core.security.jcaptcha;
 
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
 
import com.octo.captcha.Captcha;
import com.octo.captcha.service.CaptchaServiceException;
import com.octo.captcha.service.captchastore.CaptchaAndLocale;
 
 
/**
 * Simple store based on a HashMap
 */
public class SessionCaptchaStore implements CaptchaStore {
 
  HttpServletRequest request;
    HttpSession store;
    List<String> keySet;
    public static String SESSIONCAPTCHA="session_captcha";
    
    public HttpServletRequest getRequest() {
    return request;
  }
 
  public void setRequest(HttpServletRequest request) {
    this.request = request;
  }
 
  
  public SessionCaptchaStore() {
        this.keySet = new ArrayList<String>();
    }
 
    /**
     * Check if a captcha is stored for this id
     *
     * @return true if a captcha for this id is stored, false otherwise
     */
    public boolean hasCaptcha(String id) {
        return request.getSession().getAttribute(SESSIONCAPTCHA+id)!=null;
    }
 
    /**
     * Store the captcha with the provided id as key. The key is assumed to be unique, so if the same key is used twice
     * to store a captcha, the store will return an exception
     *
     * @param id      the key
     * @param captcha the captcha
     *
     * @throws CaptchaServiceException if the captcha already exists, or if an error occurs during storing routine.
     */
    public void storeCaptcha(String id, Captcha captcha) throws CaptchaServiceException {
      keySet.add(SESSIONCAPTCHA+id);
      request.getSession().setAttribute(SESSIONCAPTCHA+id, new CaptchaAndLocale(captcha));
    }
 
    /**
     * Store the captcha with the provided id as key. The key is assumed to be unique, so if the same key is used twice
     * to store a captcha, the store will return an exception
     *
     * @param id      the key
     * @param captcha the captcha
     * @param locale  the locale used that triggers the captcha generation
     * @throws com.octo.captcha.service.CaptchaServiceException
     *          if the captcha already exists, or if an error occurs during storing routine.
     */
    public void storeCaptcha(String id, Captcha captcha, Locale locale) throws CaptchaServiceException {
      keySet.add(SESSIONCAPTCHA+id);
      request.getSession().setAttribute(SESSIONCAPTCHA+id, new CaptchaAndLocale(captcha,locale));
    }
 
    /**
     * Retrieve the captcha for this key from the store.
     *
     * @return the captcha for this id
     *
     * @throws CaptchaServiceException if a captcha for this key is not found or if an error occurs during retrieving
     *                                 routine.
     */
    public Captcha getCaptcha(String id) throws CaptchaServiceException {
        Object captchaAndLocale = request.getSession().getAttribute(SESSIONCAPTCHA+id);
        return captchaAndLocale!=null?((CaptchaAndLocale) captchaAndLocale).getCaptcha():null;
    }
 
    /**
     * Retrieve the locale for this key from the store.
     *
     * @return the locale for this id, null if not found
     * @throws com.octo.captcha.service.CaptchaServiceException
     *          if an error occurs during retrieving routine.
     */
    public Locale getLocale(String id) throws CaptchaServiceException {
        Object captchaAndLocale = request.getSession().getAttribute(SESSIONCAPTCHA+id);
        return captchaAndLocale!=null?((CaptchaAndLocale) captchaAndLocale).getLocale():null;
    }
 
    /**
     * Remove the captcha with the provided id as key.
     *
     * @param id the key
     *
     * @return true if found, false otherwise
     *
     * @throws CaptchaServiceException if an error occurs during remove routine
     */
    public boolean removeCaptcha(String id) {
        if (request.getSession().getAttribute(SESSIONCAPTCHA+id) != null) {
          keySet.remove(SESSIONCAPTCHA+id);
            request.getSession().removeAttribute(SESSIONCAPTCHA+id);
            return true;
        }
        return false;
    }
 
    /**
     * get the size of this store
     */
    public int getSize() {
        return keySet.size();
    }
 
    /**
     * Return all the contained keys
     */
    public Collection getKeys() {
        return keySet;
    }
 
    /**
     * Empty the store
     */
    public void empty() {
        for (Iterator<String> iterator = keySet.iterator(); iterator.hasNext();) {
      String key = iterator.next();
      keySet.remove(key);
            request.getSession().removeAttribute(key);
    }
    }
 
  public void cleanAndShutdown() {
    // TODO Auto-generated method stub
    
  }
 
  public void initAndStart() {
    // TODO Auto-generated method stub
    
  }
}