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PHP多线程抓取网页实现代码

时间:2021-07-01 10:21:17 帮助过:28人阅读

受限于php语言本身不支持多线程,所以开发爬虫程序效率并不高,这时候往往需 要借助Curl Multi Functions 它可以实现并发多线程的访问多个url地址。既然 Curl Multi Function如此强大,能否用 Curl Multi Functions 来写并发多线程下载文件呢,当然可以,下面给出我的代码:

代码1:将获得的代码直接写入某个文件
代码如下:
  1. <br><?php <br>$urls = array( <br>'http://www.sina.com.cn/', <br>'http://www.sohu.com/', <br>'http://www.163.com/' <br>); // 设置要抓取的页面URL <br><br>$save_to='/test.txt'; // 把抓取的代码写入该文件 <br><br>$st = fopen($save_to,"a"); <br>$mh = curl_multi_init(); <br><br>foreach ($urls as $i => $url) { <br>$conn[$i] = curl_init($url); <br>curl_setopt($conn[$i], CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)"); <br>curl_setopt($conn[$i], CURLOPT_HEADER ,0); <br>curl_setopt($conn[$i], CURLOPT_CONNECTTIMEOUT,60); <br>curl_setopt($conn[$i], CURLOPT_FILE,$st); // 设置将爬取的代码写入文件 <br>curl_multi_add_handle ($mh,$conn[$i]); <br>} // 初始化 <br><br>do { <br>curl_multi_exec($mh,$active); <br>} while ($active); // 执行 <br><br>foreach ($urls as $i => $url) { <br>curl_multi_remove_handle($mh,$conn[$i]); <br>curl_close($conn[$i]); <br>} // 结束清理 <br><br>curl_multi_close($mh); <br>fclose($st); <br>?> <br> <br>代码2:将获得的代码先放入变量,再写入某个文件 <br><span><u></u></span> 代码如下:<pre class="brush:php;toolbar:false layui-box layui-code-view layui-code-notepad"><ol class="layui-code-ol"><li><br><?php <br>$urls = array( <br>'http://www.sina.com.cn/', <br>'http://www.sohu.com/', <br>'http://www.163.com/' <br>); <br><br>$save_to='/test.txt'; // 把抓取的代码写入该文件 <br>$st = fopen($save_to,"a"); <br><br>$mh = curl_multi_init(); <br>foreach ($urls as $i => $url) { <br>$conn[$i] = curl_init($url); <br>curl_setopt($conn[$i], CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)"); <br>curl_setopt($conn[$i], CURLOPT_HEADER ,0); <br>curl_setopt($conn[$i], CURLOPT_CONNECTTIMEOUT,60); <br>curl_setopt($conn[$i],CURLOPT_RETURNTRANSFER,true); // 设置不将爬取代码写到浏览器,而是转化为字符串 <br>curl_multi_add_handle ($mh,$conn[$i]); <br>} <br><br>do { <br>curl_multi_exec($mh,$active); <br>} while ($active); <br><br>foreach ($urls as $i => $url) { <br>$data = curl_multi_getcontent($conn[$i]); // 获得爬取的代码字符串 <br>fwrite($st,$data); // 将字符串写入文件。当然,也可以不写入文件,比如存入数据库 <br>} // 获得数据变量,并写入文件 <br><br>foreach ($urls as $i => $url) { <br>curl_multi_remove_handle($mh,$conn[$i]); <br>curl_close($conn[$i]); <br>} <br><br>curl_multi_close($mh); <br>fclose($st); <br>?> <br></li><li> </li><li> </li></ol></pre>

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