Question

我的代码片段如下所示 - 正如您所看到的，我有一个try-catch块，但是尽管如此，我仍然会得到一个未被捕获的异常，它会终止整个应用程序。我错过了什么？

try {
    $cakeXml = simplexml_load_string($xml);
    $parseSuccess = $cakeXml->xpath('//ParseSuccess');
} catch (Exception $ex) {
    $response['parseSuccess'] = false;
    $response['errors']['ParseError'] = 'An unknown error occurred while trying to parse the file. Please try again';
    return $response;       
}

2014-12-16 22:45:12 Error: Fatal Error (1): Call to a member function xpath() on a non-object
2014-12-16 22:45:12 Error: [FatalErrorException] Call to a member function xpath() on a non-object

Answer 1

如果您更仔细地阅读错误消息，您会发现Exception上没有消息，而是Fatal Error。 try/catch语句无法捕获PHP中的致命错误，因为无法从致命错误中恢复。

至于解决此问题，您的错误告诉您$cakeXml是非对象。一种解决方案是做这样的事情。

try {
    $cakeXml = simplexml_load_string($xml);
    if (!is_object($cakeXml)) {
        throw new Exception('simplexml_load_string returned non-object');
    }
    $parseSuccess = $cakeXml->xpath('//ParseSuccess');
} catch (Exception $ex) {
    $response['parseSuccess'] = false;
    $response['errors']['ParseError'] = 'An unknown error occurred while trying to parse the file. Please try again';
    return $response;       
}

Answer 2

DOMXPath方法，即xpath或evaluate不会抛出异常。因此，您需要显式验证并抛出异常。

见下面的代码片段：

$xml_1= "";

try {    
    $cakeXml = simplexml_load_string($xml_1);        
    if ( !is_object($cakeXml) ) {
        throw new Exception(sprintf('Not an object (Object: %s)', var_export($cakeXml, true)));
    } else {        
        $parseSuccess = $cakeXml->xpath('//pages');                
        print('<pre>');print_r($parseSuccess);
    }
} catch (Exception $ex) {
    echo 'Caught exception: ',  $ex->getMessage(), "\n";        
}

PHP中的XML异常未被捕获

2 个答案: