只有两个php API真正适合处理大文件。第一个是旧的expatapi，第二个是较新的XMLreader函数。这些api读取连续流，而不是将整个树加载到内存中（这是simplexml和DOM所做的）。
例如，您可能需要查看DMOZ目录的部分解析器：
<?phpclass SimpleDMOZParser{ protected $_stack = array(); protected $_file = ""; protected $_parser = null; protected $_currentId = ""; protected $_current = ""; public function __construct($file) { $this->_file = $file; $this->_parser = xml_parser_create("UTF-8"); xml_set_object($this->_parser, $this); xml_set_element_handler($this->_parser, "startTag", "endTag"); } public function startTag($parser, $name, $attribs) { array_push($this->_stack, $this->_current); if ($name == "TOPIC" && count($attribs)) { $this->_currentId = $attribs["R:ID"]; } if ($name == "link" && strpos($this->_currentId, "Top/Home/Consumer_Information/Electronics/") === 0) { echo $attribs["R:RESOURCE"] . "n"; } $this->_current = $name; } public function endTag($parser, $name) { $this->_current = array_pop($this->_stack); } public function parse() { $fh = fopen($this->_file, "r"); if (!$fh) { die("Epic fail!n"); } while (!feof($fh)) { $data = fread($fh, 4096); xml_parse($this->_parser, $data, feof($fh)); } }}$parser = new SimpleDMOZParser("content.rdf.u8");$parser->parse();
