zf2提供了图片验证码Zend\Captcha\Image和符号字符验证码Zend\Captcha\Figlet，图片验证码是网站应用中见得比较多的一种验证码，本文以图片验证码为例。

    如果用session来临时保存生成的验证码，就需要先配置session。

    session的参数配置：

// /config/autoload/local.php

return array(
    'session' => array(
        'config' => array(
            'class' => 'Zend\Session\Config\SessionConfig',
            'options' => array(
                'name' => 'zf2ttttt',
            ),
        ),
        'storage' => 'Zend\Session\Storage\SessionArrayStorage',
        'validators' => array(
            'Zend\Session\Validator\RemoteAddr',
            'Zend\Session\Validator\HttpUserAgent',
        ),
    ),
);

    Application启动后调用session_start：

// /module/Application/Module.php

namespace Application;

use Zend\Mvc\ModuleRouteListener;
use Zend\Mvc\MvcEvent;

use Zend\Session\SessionManager;
use Zend\Session\Container;

class Module
{
    public function onBootstrap(MvcEvent $e)
    {
        $eventManager        = $e->getApplication()->getEventManager();
        $moduleRouteListener = new ModuleRouteListener();
        $moduleRouteListener->attach($eventManager);
        
	//为表单验证对象设置默认的语言翻译器，以便验证码验证不通过时用默认语言提示用户       
       \Zend\Validator\AbstractValidator::setDefaultTranslator($e->getApplication()->getServiceManager()->get('translator'));
       //启动session
       $this->bootstrapSession($e);
    }

    public function bootstrapSession($e){
        $session = $e->getApplication()->getServiceManager()->get('Zend\Session\SessionManager');
        $session->start();        
    }

    //SessionManager工厂
    public function getServiceConfig() {
        return array(
            'factories' => array(
                'Zend\Session\SessionManager' => function ($sm) {
                    $config = $sm->get('config');
                    if (isset($config['session'])){
                        $session = $config['session'];
                        
                        $sessionConfig = null;
                        if (isset($session['config'])){
                            $class = isset($session['config']['class']) ? $session['config']['class'] : 'Zend\Session\Config\SessionConfig';
                            $options = isset($session['config']['options']) ? $session['config']['options'] : array();
                            $sessionConfig = new $class;
                            $sessionConfig->setOptions($options);
                        }
                        
                        $sessionStorage = null;
                        if (isset($session['storage'])){
                            $class = $session['storage'];
                            $sessionStorage = new $class;
                        }
                        
                        $sessionSaveHandler = null;
                        if (isset($session['save_handler'])){
                            $sessionSaveHandler = $sm->get($session['save_handler']);
                        }
                        
                        $sessionManager = new SessionManager($sessionConfig, $sessionStorage, $sessionSaveHandler);
                    } else {
                        $sessionManager = new SessionManager();
                    }
                    Container::setDefaultManager($sessionManager);
                    return $sessionManager;
                },
            ),
        );
    }
}

    表单Form中添加验证码输入：验证码就是一张图片，可以在表单中用一个text让用户输入验证码，text旁显示验证码图片：

// /module/Test/src/Test/Form/TestForm.php

namespace Test\Form;

......

use Test\Form\MyImgCaptchaValidator;//自定义的验证码检验类

class TestForm extends Form  implements InputFilterProviderInterface{

    ......

    public function __construct($name = null) {
        
        ......

        //添加验证码输入框
        $this->add(array(
            'name' => 'cv',
            'type' => 'Text',
            'options' => array(
                'label' => '请输入检验码：',                
            ),
            'attributes' => array(
                'size' => 20,
                'maxlength' => 4,
            ),
        ));

        ......
    }

    public function getInputFilterSpecification() {
        
        ......

        //自定义的验证码检验对象
        $captchaValidator = new MyImgCaptchaValidator();

        ......

        return array(
            ......

            'cv' => array(
                'required' => true,
                'filters'  => array(
                    array('name' => 'StringTrim'),
                    array('name' => 'StringToLower'),
                ),
                'validators' => array(
                    array('name' => 'NotEmpty'),
                    array(
                        'name'    => 'StringLength',//本例将验证码长度限制为4字符
                        'options' => array(
                            'encoding' => 'UTF-8',
                            'min'      => 4,
                            'max'      => 4,
                        ),
                    ),
                $captchaValidator,
                ),
            ),
        );
    }
}

    自定义的验证码验证类：

// /module/Test/src/Test/Form/MyImgCaptchaValidator.php

namespace Test\Form;

use Zend\Validator\AbstractValidator;
use Zend\Session\Storage\SessionArrayStorage;

class MyImgCaptchaValidator extends AbstractValidator {

    const DIFFERENT = 'different';
    protected $messageTemplates = array(
        self::DIFFERENT => "Capthca inputted is different !",//此处为字符串的key，如果语言文件配置了该字符串，并且为validator设置了默认的tranlaotr，validator基类会自动翻译该字符串
    );

    public function isValid($value) {
        
        $this->setValue($value);
        
        $isValid = true;
        
        $sessionKey_Capthca = 'sesscaptcha';
        $sessionStorage = new SessionArrayStorage();
        $captchaWord = $sessionStorage->offsetGet($sessionKey_Capthca);//获取session临时保存的验证码
        $wd = $captchaWord;
        if ($wd != $value){//比较输入的验证码和生成的验证码
            $this->error(self::DIFFERENT);//输入不正确，则设置错误消息
            $isValid = false;
        }
        return $isValid;
    }

}

    在视图中输出验证码输入框和验证码图片：

// /module/Test/src/view/test/test/testform.phtml

echo '<div>';

$captcha = $this->tform->get('cv');//获取验证码输入框表单元素

echo $formLabel->openTag().$captcha->getOption('label');

echo $this->formInput($captcha);//显示验证码输入框

echo '<img src=http://www.mamicode.com/"'.$imgSrc.'">