PHP用SAX解析XML的实现代码与问题分析

<br><?php <br>$g_books = array(); <br>$g_elem = null; <br>function startElement( $parser, $name, $attrs ) <br>{ <br>global $g_books, $g_elem; <br>if ( $name == 'BOOK' ) $g_books []= array(); <br>$g_elem = $name; <br>} <br>function endElement( $parser, $name ) <br>{ <br>global $g_elem; <br>$g_elem = null; <br>} <br>function textData( $parser, $text ) <br>{ <br>global $g_books, $g_elem; <br>if ( $g_elem == 'AUTHOR' || <br>$g_elem == 'PUBLISHER' || <br>$g_elem == 'TITLE' ) <br>{ <br>$g_books[ count( $g_books ) - 1 ][ $g_elem ] = $text; <br>} <br>} <br>$parser = xml_parser_create(); <br>xml_set_element_handler( $parser, "startElement", "endElement" ); <br>xml_set_character_data_handler( $parser, "textData" ); <br>$f = fopen( 'books.xml', 'r' ); <br>while( $data = fread( $f, 4096 ) ) <br>{ <br>xml_parse( $parser, $data ); <br>} <br>xml_parser_free( $parser ); <br>foreach( $g_books as $book ) <br>{ <br>echo $book['TITLE']." - ".$book['AUTHOR']." - "; <br>echo $book['PUBLISHER']."\n"; <br>} <br>?> <br><br><strong>PHP中用SAX方式解析XML发现的问题 <br></strong>XML如下： <br>so.xml <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><?xml version="1.0" encoding="GBK"?> <br><result> <br><row> <br><id>1047869</id> <br><date>2008-08-28 14:54:51</date> <br><title>红花还需绿叶扶--浅谈脚架云台的选购</title> <br><summary>很多专业摄影师在选购三脚架的时候，往往出手阔绰，3、4000元一个的捷信或者曼富图三脚架常常不用经过思考就买下来了，可是，他们却总是忽视了云台的精挑细眩其实，数码相机架在三脚架上面究竟稳不稳，起决定作用的是云台，那么我们如何才能挑选到一款稳如磐石的云台呢？云台家族种类繁多用途迥异简单的说，脚架云台是用于连接相机与脚架进行角度调节的部件，主要分成三维云台和球型云台。三维云台在横向旋转</summary> <br></row> <br>...(省略若干行) <br></result> <br> <br>xml_class.php <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>class xml { <br>var $parser; <br>var $i =0; <br>var $search_result = array(); <br>var $row = array(); <br>var $data = array(); <br>var $now_tag; <br>var $tags = array("ID", "CLASSID", "SUBCLASSID", "CLASSNAME", "TITLE", "SHORTTITLE", "AUTHOR", "PRODUCER", "SUMMARY", "CONTENT", "DATE"); <br>function xml() <br>{ <br>$this->parser = xml_parser_create(); <br>xml_set_object($this->parser, $this); <br>xml_set_element_handler($this->parser, "tag_open", "tag_close"); <br>xml_set_character_data_handler($this->parser, "cdata"); <br>} <br>function parse($data) <br>{ <br>xml_parse($this->parser, $data); <br>} <br>function tag_open($parser, $tag, $attributes) <br>{ <br>$this->now_tag=$tag; <br>if($tag=='RESULT') { <br>$this->search_result = $attributes; <br>} <br>if($tag=='ROW') { <br>$this->row[$this->i] = $attributes; <br>} <br>} <br>function cdata($parser, $cdata) <br>{ <br>if(in_array($this->now_tag, $this->tags)){ <br>$tagname = strtolower($this->now_tag); <br>$this->data[$this->i][$tagname] = $cdata; <br>} <br>} <br>function tag_close($parser, $tag) <br>{ <br>$this->now_tag=""; <br>if($tag=='ROW') { <br>$this->i++; <br>} <br>} <br>} <br>?> <br> <br>search.php <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>require_once("./xml_class.php"); <br>$xml = file_get_contents("./so.xml"); <br>$xml_parser = new xml(); <br>$xml_parser->parse($xml); <br>print_r($xml_parser); <br>?> <br> <br>最后得到的结果中summary中的数据少了很多，总是得不到完整的summary内容。有时还会得到乱码，在网上也找了半天也不知道是什么问题引起的。 <br>　　后来才发现问题是因为xml_parser解析XML是循环处理节点中的数据的，每次只取大概300个字符长度(具体是多少，我也不太清楚，只是用strlen</li></ol></pre>输出大概在300左右),于是才知道是因为每次的循环就会把前次的数据给复盖了，这样就会出现数据不全的问题。 <br>　　解决办法就是把xml_class文件中的xml类中的cdata方法中$this->data[$this->i][$tagname] = $cdata;改为$this->data[$this->i][$tagname] .= $cdata;即可解决(其中有一些NOTICE错误，PHP已忽略了). <br></li><li>            </li><li>                                </li></ol></pre></li></ol></pre>