<?php
require_once 'Zend/Filter/StringToLower.php';  //加载子类
$filter = new Zend_Filter_StringToLower;    //实例化对象
$temp1 = "ABCDefGH";              //定义待过滤内容
$temp2 = "我爱Nan Jing";
echo "内容：".$temp1."<p>经过滤后为：";
echo $filter->filter($temp1);
echo "<p>";
echo "内容：".$temp2."<p>经过滤后为：";
echo $filter->filter($temp2);

class Zend_Filter_StringToLower implements Zend_Filter_Interface
{
  /**
   * Encoding for the input string
   *
   * @var string
   */
  protected $_encoding = null;
  /**
   * Constructor
   *
   * @param string|array|Zend_Config $options OPTIONAL
   */
  public function __construct($options = null)
  {
    if ($options instanceof Zend_Config) {
      $options = $options->toArray();
    } else if (!is_array($options)) {
      $options = func_get_args();
      $temp  = array();
      if (!empty($options)) {
        $temp['encoding'] = array_shift($options);
      }
      $options = $temp;
    }
    if (!array_key_exists('encoding', $options) && function_exists('mb_internal_encoding')) {
      $options['encoding'] = mb_internal_encoding();
    }
    if (array_key_exists('encoding', $options)) {
      $this->setEncoding($options['encoding']);
    }
  }
  /**
   * Returns the set encoding
   *
   * @return string
   */
  public function getEncoding()
  {
    return $this->_encoding;
  }
  /**
   * Set the input encoding for the given string
   *
   * @param string $encoding
   * @return Zend_Filter_StringToLower Provides a fluent interface
   * @throws Zend_Filter_Exception
   */
  public function setEncoding($encoding = null)
  {
    if ($encoding !== null) {
      if (!function_exists('mb_strtolower')) {
        require_once 'Zend/Filter/Exception.php';
        throw new Zend_Filter_Exception('mbstring is required for this feature');
      }
      $encoding = (string) $encoding;
      if (!in_array(strtolower($encoding), array_map('strtolower', mb_list_encodings()))) {
        require_once 'Zend/Filter/Exception.php';
        throw new Zend_Filter_Exception("The given encoding '$encoding' is not supported by mbstring");
      }
    }
    $this->_encoding = $encoding;
    return $this;
  }
  /**
   * Defined by Zend_Filter_Interface
   *
   * Returns the string $value, converting characters to lowercase as necessary
   *
   * @param string $value
   * @return string
   */
  public function filter($value)
  {
    if ($this->_encoding !== null) {
      return mb_strtolower((string) $value, $this->_encoding);
    }
    return strtolower((string) $value);
  }
}

if ($options instanceof Zend_Config) {
  $options = $options->toArray();
} else if (!is_array($options)) {
  $options = func_get_args();
  $temp  = array();
  if (!empty($options)) {
    $temp['encoding'] = array_shift($options);
  }
  $options = $temp;
}
if (!array_key_exists('encoding', $options) && function_exists('mb_internal_encoding')) {
  $options['encoding'] = mb_internal_encoding();
}
if (array_key_exists('encoding', $options)) {
  $this->setEncoding($options['encoding']);
}

<?php
require_once 'Zend/Filter.php';         //加载Zend_Filter类
require_once 'Zend/Filter/Alpha.php';      //加载Zend_Filter_Alpha子类
require_once 'Zend/Filter/StringToUpper.php';  //加载Zend_Filter_StringToUpper子类
$filterChain = new Zend_Filter();        //创建过滤器链
$filterChain ->addFilter(new Zend_Filter_Alpha(" "))
  ->addFilter(new Zend_Filter_StringToUpper());//向过滤器链中添加过滤器
$temp1 = "12345asdf67asdfasdf";
$temp2 = "#$%^!@fffff";
$temp3 = "Welcome to Bei Jing";
echo "内容:".$temp1."<p>经过过滤后为：";
echo $filterChain->filter($temp1);
echo "<p>";
echo "内容:".$temp2."<p>经过过滤后为：";
echo $filterChain->filter($temp2);
echo "<p>";
echo "内容:".$temp3."<p>经过过滤后为：";
echo $filterChain->filter($temp3);
echo "<p>";

public function filter($value)
{
    $whiteSpace = $this->allowWhiteSpace ? '\s' : '';
    if (!self::$_unicodeEnabled) {
      // POSIX named classes are not supported, use alternative a-zA-Z match
      $pattern = '/[^a-zA-Z' . $whiteSpace . ']/';
    } else if (self::$_meansEnglishAlphabet) {
      //The Alphabet means english alphabet.
      $pattern = '/[^a-zA-Z' . $whiteSpace . ']/u';
    } else {
      //The Alphabet means each language's alphabet.
      $pattern = '/[^\p{L}' . $whiteSpace . ']/u';
    }
    return preg_replace($pattern, '', (string) $value);
}

public function __construct($allowWhiteSpace = false)
{
    if ($allowWhiteSpace instanceof Zend_Config) {
      $allowWhiteSpace = $allowWhiteSpace->toArray();
    } else if (is_array($allowWhiteSpace)) {
      if (array_key_exists('allowwhitespace', $allowWhiteSpace)) {
        $allowWhiteSpace = $allowWhiteSpace['allowwhitespace'];
      } else {
        $allowWhiteSpace = false;
      }
    }
    $this->allowWhiteSpace = (boolean) $allowWhiteSpace;
    if (null === self::$_unicodeEnabled) {
      self::$_unicodeEnabled = (@preg_match('/\pL/u', 'a')) ? true : false;
    }
    if (null === self::$_meansEnglishAlphabet) {
      $this->_locale = new Zend_Locale('auto');
      self::$_meansEnglishAlphabet = in_array($this->_locale->getLanguage(),
      array('ja', 'ko', 'zh')
      );
    }
}

/**
* Returns the allowWhiteSpace option
*
* @return boolean
*/
public function getAllowWhiteSpace()
{
    return $this->allowWhiteSpace;
}
/**
* Sets the allowWhiteSpace option
*
* @param boolean $allowWhiteSpace
* @return Zend_Filter_Alpha Provides a fluent interface
*/
public function setAllowWhiteSpace($allowWhiteSpace)
{
    $this->allowWhiteSpace = (boolean) $allowWhiteSpace;
    return $this;
}

public function filter($value)
{
    $whiteSpace = $this->allowWhiteSpace ? '\s' : '';
    if (!self::$_unicodeEnabled) {
      // POSIX named classes are not supported, use alternative a-zA-Z0-9 match
      $pattern = '/[^a-zA-Z0-9' . $whiteSpace . ']/';
    } else if (self::$_meansEnglishAlphabet) {
      //The Alphabet means english alphabet.
      $pattern = '/[^a-zA-Z0-9' . $whiteSpace . ']/u';
    } else {
      //The Alphabet means each language's alphabet.
      $pattern = '/[^\p{L}\p{N}' . $whiteSpace . ']/u';
    }
    return preg_replace($pattern, '', (string) $value);
}

<?php
require_once 'Zend/Filter/Htmlentities.php';
$filter = new Zend_Filter_HtmlEntities();
$temp1 = "<img src = './1.png' width='100px'>";
$temp2 = "<button>aaa</button>";
$temp3 = "<h1>Welcome to Bei Jing</h1>";
echo "内容:".$temp1."<p>经过过滤为：";
echo $filter->filter($temp1);
echo "<p>";
echo "内容:".$temp2."<p>经过过滤为：";
echo $filter->filter($temp2);
echo "<p>";
echo "内容:".$temp3."<p>经过过滤为：";
echo $filter->filter($temp3);
echo "<p>";