php获取内容第一张图片

<?php

    $test = '<p><a href="aa.jpg">444</a><img height="768" width="1024" alt="" src="/uploadfiles/28/Tree.jpg" /></p>

    <p>444<img height="768" width="1024" alt="" src="http://www.abcdefg.com/uploadfiles/sf/Tree.jpg" /></p>

    fsdafasdfasdfasdf

    <p>444<img height="768" width="1024" alt="" src="/uploadfiles/28/elm.jpg" /></p>sdfasdfasdf<p>

    <p>444<img height="768" width="1024" alt="" src="/uploadfiles/28/maple.jpg" /></p>dgdgrfdgdf

    <p>444<img height="768" width="1024" alt="" src="/uploadfiles/40/Tree.jpg" /></p>';

 

//方法一：

preg_match_all("/src=\"\/?(.*?)\"/",$test,$match);
//print_r($match[1]);
echo($match[1][0]);
 

//方法二：

  preg_match ("<img.*src=[\"](.*?)[\"].*?>",$test,$match);

  echo "$match[1]";

?>

PHP通过正则表达式下载图片到本地的实现代码 

代码如下:

<?php 

 

set_time_limit(0);//抓取不受时间限制 

$URL='http://pp.baidu.com/';//任意网址 

get_pic($URL); 

function get_pic($pic_url) { 

//获取图片二进制流 

$data=CurlGet($pic_url); 

 

$pattern_src = '/<[img|IMG].*?src=[\'|\"](.*?(?:[\.gif|\.jpg]))[\'|\"].*?[\/]?>/'; 

$num = preg_match_all($pattern_src, $data, $match_src); 

$arr_src=$match_src[1];//获得图片数组 

get_name($arr_src); 

echo "<br>finished!!!"; 

return 0; 

} 

 

function get_name($pic_arr) 

{ 

//图片类型 

$pattern_type = '/(/.(jpg|bmp|jpeg|gif|png))/'; 

foreach($pic_arr as $pic_item){//循环取出每幅图的地址 

$num = preg_match_all($pattern_type, $pic_item, $match_type); 

$pic_name = get_unique().$match_type[1][0];//改时微秒时间戳命名 

//以流的形式保存图片 

$write_fd = @fopen($pic_name,"wb"); 

@fwrite($write_fd, CurlGet($pic_item)); 

@fclose($write_fd); 

echo "[OK]..!"; 

} 

return 0; 

} 

//通过微秒时间获得唯一ID 

function get_unique(){ 

list($msec, $sec) = explode(" ",microtime()); 

return $sec.intval($msec*1000000); 

} 

//抓取网页内容 

function CurlGet($url){ 

$url=str_replace('&','&',$url); 

$curl = curl_init(); 

curl_setopt($curl, CURLOPT_URL, $url); 

curl_setopt($curl, CURLOPT_HEADER, false); 

//curl_setopt($curl, CURLOPT_REFERER,$url); 

curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 6.0; SeaPort/1.2; Windows NT 5.1; SV1; InfoPath.2)"); 

curl_setopt($curl, CURLOPT_COOKIEJAR, 'cookie.txt'); 

curl_setopt($curl, CURLOPT_COOKIEFILE, 'cookie.txt'); 

curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); 

curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 0); 

$values = curl_exec($curl); 

curl_close($curl); 

return $values; 

} 

?>