Question

我有这项方案,有了一个开关:

$htmlContent = file_get_contents( http://somesite.com );
$htmlDOM->loadHTML( $htmlContent );
$htmlXPath = new DOMXPath( $htmlDOM );

for($i = 0; $i <= 16; $i++ ) {
    switch($i) {
        case 0:
            $link = utf8_decode($htmlXPath->query( /html/body/div[2]/div[2]/div/div/div/div/div[2]/div/a )->item(0)->getAttribute( href ));
            break;
        case 1:
            $link = utf8_decode($htmlXPath->query( /html/body/div[2]/div[2]/div/div/div/div/ul/li/div/a )->item(0)->getAttribute( href ));
            break;
        default:
            $link = utf8_decode($htmlXPath->query( /html/body/div[2]/div[2]/div/div/div/div/ul/li[  . $i .  ]/div/a )->item(0)->getAttribute( href ));
            break;
    }
}

对于案件0和案件1,如预期,但因违约,将出现这一错误:

PHP Fatal error:  Call to a member function getAttribute() on a non-object

我可以想象,这是因为一美元而发生的,但我如何能够解决这一问题?

帮助!

Answer 1

Most likely the query s failing to find anything and returning a zero-length node list. Attempting to fetch a node from an empty list returns false, not an object.

不是接手盘问,而是使用中间持有人检查:

$nodes = $htmlXPath->query( /html/body/div[2]/div[2]/div/div/div/div/div[2]/div/a );
if ($nodes->length > 0) {
   $link = $nodes->item(0)->getAttribute( href ));
}

友情链接