PHP实现的一个简单的爬虫

下面是代码：

//爬虫类classCrawler{private$url;
    publicfunction__construct($url){if(!preg_match("/^(http)s?/", $url)){
            $url = "http://".$url;
        }
        $this->url = $url;
    }
    //从给定的url中获取html内容protectedfunction_getUrlContent($url){
        @$handle = fopen($url, "r");
        if(error_get_last()){//捕获异常（不一定是错误）$err = newException("你的URL好像不对！要不换一个？");
            echo$err->getMessage();
            return;
        }
        if($handle){
            $content = stream_get_contents($handle,1024*1024);//将资源流读入字符串return$content;
        }else{
            returnfalse;
        }   
    }
    //从html内容中筛选链接protectedfunction_filterUrl($web_content){$reg_tag_a = '/<[a|A].*?href=[\'\"]{0,1}([^>\'\"\ ]*).*?>/';
        $result = preg_match_all($reg_tag_a,$web_content,$match_result);
        if($result){
            return$match_result[1];
        }
    }
    //判断是否是完整的urlprotectedfunction_judgeURL($url){$url_info = parse_url($url);
        if(isset($url_info['scheme'])||isset($url_info['host'])){
            returntrue;
        }
        returnfalse;
    }
    //修正相对路径protectedfunction_reviseUrl($base_url,$url_list){$url_info = parse_url($base_url);//分解url中的各个部分unset($base_url);
        $base_url = isset($url_info["scheme"])?$url_info["scheme"].'://':"";//$url_info["scheme"]为http、ftp等if(isset($url_info["user"]) && isset($url_info["pass"])){//记录用户名及密码的url$base_url .= $url_info["user"].":".$url_info["pass"]."@";
        }
        $base_url .= isset($url_info["host"])?$url_info["host"]:"";//$url_info["host"]域名if(isset($url_info["port"])){//$url_info["port"]端口，8080等$base_url .= ":".$url_info["port"];
        }
        $base_url .= isset($url_info["path"])?$url_info["path"]:"";//$url_info["path"]路径//目前为止，绝对路径前面已经组装完if(is_array($url_list)){
            foreach ($url_listas$url_item) {
                // if(preg_match('/^(http)s?/',$url_item)){if($this->_judgeURL($url_item)){
                    //已经是完整的url$result[] = $url_item;
                }else {
                    //不完整的url$real_url = $base_url.$url_item;
                    $result[] = $real_url;
                }
            }
            return$result;
        }else {
            return;
        }
    }
    //爬虫publicfunctioncrawler(){$content = $this->_getUrlContent($this->url);
        if($content){
            $url_list = $this->_reviseUrl($this->url,$this->_filterUrl($content));
            if($url_list){
                return$url_list;
            }else {
                return ;
            }
        }else{
            return ;
        }
    }
}


$fp_puts = fopen("url.txt","ab");//记录url列表$fp_gets = fopen("url.txt","r");//保存url列表$current_url = "www.baidu.com";
do{
    $Crawler = new Crawler($current_url);
    $url_arr = $Crawler->crawler();
    if($url_arr){
        foreach ($url_arras$url) {
            fputs($fp_puts,$url."\n");
        }
    }
}while ($current_url = fgets($fp_gets,1024));//不断获得url// echo "
";// var_dump($url_arr);// echo "
";?>
由于在循环的时候要new的对象可能会很多，当时想的是用单例模式解决，以免内存开销太大，后来嫌麻烦就不了了之了。。。。
').addClass('pre-numbering').hide();
                    $(this).addClass('has-numbering').parent().append($numbering);
                    for (i = 1; i <= lines; i++) {
                        $numbering.append($('
').text(i));
                    };
                    $numbering.fadeIn(1700);
                });
            });
        
                
                
                

                    以上就介绍了PHP实现的一个简单的爬虫，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。