浅析PHP关键词替换的类(避免重复替换，保留与还原原始链接)，浅析关键词_PHP教程

<&#63;php
 /* 
  * 关键词匹配类
  * @author ylx <ylx@gmail.com>
  * @packet mipang
  * 使用实例
  * $str = "绿壳蛋鸡撒范德萨下一年，下一年的洒落开房间卢卡斯地方军";
  * $key = new KeyReplace($str,array("xxxx"=>"sadf","下一年"=>'http://baidu.com',"下一年"=>'google.com'));
  * echo $key->getResultText();
  * echo $key->getRuntime();
  */
class KeyReplace
{
 private $keys = array();
 private $text = "";
 private $runtime = ;
 private $url = true;
 private $stopkeys = array();
 private $all = false;
 /**
  * @access public  
  * @param string $text 指定被处理的文章
  * @param array $keys 指定字典词组array(key=>url,...) url可以是数组，如果是数组将随机替换其中的一个
  * @param array $stopkeys 指定停止词array(key,...) 这里面的词将不会被处理
  * @param boolean $url true 表示替换成链接否则只替换
  * @param boolean $all true 表示替换所有找到的词，否则只替换第一次
  */
 public function __construct($text='',$keys=array(),$url=true,$stopkeys=array(),$all=false) {
  $this->keys = $keys;
  $this->text = $text;
  $this->url = $url;
  $this->stopkeys = $stopkeys;
  $this->all = $all;
 }
 /**
  * 获取处理好的文章
  * @access public  
  * @return string text
  */
 public function getResultText() {
  $start = microtime(true);
  $keys = $this->hits_keys();
  $keys_tmp = array_keys()($keys);
  function cmp($a, $b){
   if (mb_strlen($a) == mb_strlen($b)) {
 return ;
   }
   return (mb_strlen($a) < mb_strlen($b)) &#63; : -;
  }
  usort($keys_tmp,"cmp");
  foreach($keys_tmp as $key){
   if(is_array($keys[$key])){
 $url = $keys[$key][rand(,count($keys[$key])-)];
   }else
 $url = $keys[$key];
   $this->text = $this->r_s($this->text,$key,$url);
  }
  $this->runtime = microtime(true)-$start;
  return $this->text;
 }
 /**
  * 获取处理时间
  * @access public  
  * @return float 
  */
 public function getRuntime() {
  return $this->runtime;
 }
 /**
  * 设置关键词
  * @access public  
  * @param array $keys array(key=>url,...)
  */
 public function setKeys($keys) {
  $this->keys = $keys;
 }
 /**
  * 设置停止词
  * @access public  
  * @param array $keys array(key,...)
  */
 public function setStopKeys($keys) {
  $this->stopkeys = $keys;
 }
 /**
  * 设置文章
  * @access public  
  * @param string $text 
  */
 public function setText($text) {
  $this->text = $text;
 }
 /**
  * 用来找到字符串里面命中的关键词
  * @access public
  * @return array $keys 返回匹配到的词array(key=>url,...)
  */
 public function hits_keys(){
  $ar = $this->keys;
  $ar = $ar&#63;$ar:array();
  $result=array();
  $str = $this->text;
  foreach($ar as $k=>$url){
   $k = trim($k);
   if(!$k)
 continue;
   if(strpos($str,$k)!==false && !in_array($k,$this->stopkeys)){
 $result[$k] = $url;
   }
  }
  return $result&#63;$result:array();
 }
 /**
  * 用来找到字符串里面命中的停止词
  * @access public
  * @return array $keys 返回匹配到的词array(key,...)
  */
 public function hits_stop_keys(){
  $ar = $this->stopkeys;
  $ar = $ar&#63;$ar:array();
  $result=array();
  $str = $this->text;
  foreach($ar as $k){
   $k = trim($k);
   if(!$k)
 continue;
   if(strpos($str,$k)!==false && in_array($k,$this->stopkeys)){
 $result[] = $k;
   }
  }
  return $result&#63;$result:array();
 }
 /**
  * 处理替换过程 
  * @access private
  * @param string $text 被替换者
  * @param string $key 关键词
  * @param string $url 链接
  * @return string $text 处理好的文章
  */
 private function r_s($text,$key,$url){
  $tmp = $text;
  $stop_keys = $this->hits_stop_keys();
  $stopkeys = $tags = $a = array();
  if(preg_match_all("#<a[^>]+>[^<]*</a[^>]*>#su",$tmp,$m)){
   $a=$m[];
   foreach($m[] as $k=>$z){
 $z = preg_replace("#\##s","\#",$z);
 $tmp = preg_replace('#'.$z.'#s',"[_a".$k."_]",$tmp,);
   }
  };
  if(preg_match_all("#<[^>]+>#s",$tmp,$m)){
   $tags = $m[];
   foreach($m[] as $k=>$z){
 $z = preg_replace("#\##s","\#",$z);
 $tmp = preg_replace('#'.$z.'#s',"[_tag".$k."_]",$tmp,);
   }
  }
  if(!empty($stop_keys)){
   if(preg_match_all("#".implode("|",$stop_keys)."#s",$tmp,$m)){
 $stopkeys = $m[];
 foreach($m[] as $k=>$z){
  $z = preg_replace("#\##s","\#",$z);
  $tmp = preg_replace('#'.$z.'#s',"[_s".$k."_]",$tmp,);
 }
   }
  }
  $key = preg_replace("#([\#\(\)\[\]\*])#s","\\\\$",$key);
  if($this->url)
   $tmp = preg_replace("#(&#63;!\[_s|\[_a|\[_|\[_t|\[_ta|\[_tag)".$key."(&#63;!ag\d+_\]|g\d+_\]|\d+_\]|s\d+_\]|_\])#us",'<a href="'.$url.'">'.$key.'</a>',$tmp,$this->all&#63;-:);
  else
   $tmp = preg_replace("#(&#63;!\[_s|\[_a|\[_|\[_t|\[_ta|\[_tag)".$key."(&#63;!ag\d+_\]|g\d+_\]|\d+_\]|s\d+_\]|_\])#us",$url,$tmp,$this->all&#63;-:);
  if(!empty($a)){
   foreach($a as $n=>$at){
 $tmp = str_replace("[_a".$n."_]",$at,$tmp);
   }  
  }  
  if(!empty($tags)){
   foreach($tags as $n=>$at){
 $tmp = str_replace("[_tag".$n."_]",$at,$tmp);
   }  
  }  
  if(!empty($stopkeys)){
   foreach($stopkeys as $n=>$at){
 $tmp = str_replace("[_s".$n."_]",$at,$tmp);
   }  
  }  
  return $tmp;
 }
}