学习php(四种方法读写XML文件)

本文转载自博客园,作者:疯一样的狼人,原文标题为“PHP读写XML文件的四种方法”。

PHP对XML文件进行读写操作的方法一共有四种,分别是:字符串方式直接读写、DOMDocument读写、XMLWrite写和XMLReader读、SimpleXML读写,本文将依次对这四种方法进行介绍。

介绍之前首先对本文例子使用的数据和文件进行说明。本文写XML文件的例子都是从MySQL中读取数据然后写入到XML文件中,读XML文件的例子都是从XML文件中读取数据后组装成数组的格式,数组中每个元素对应数据库中的一条记录。

MySQL中的数据:

李炎恢php读写XML文件的四种方法
李炎恢php读写XML文件的四种方法

XML文件:

<?xml version=”1.0″ encoding=”utf8″?>
<studentcareer>
<period>
<starttime>2000</starttime>
<endtime>2002</endtime>
<school>培新小学</school>
</period>
<period>
<starttime>2002</starttime>
<endtime>2006</endtime>
<school>览表东阳学校</school>
</period>
<period>
<starttime>2006</starttime>
<endtime>2009</endtime>
<school>惠来慈云实验中学</school>
</period>
<period>
<starttime>2009</starttime>
<endtime>2012</endtime>
<school>惠来一中</school>
</period>
<period>
<starttime>2012</starttime>
<endtime>2016</endtime>
<school>华南师范大学</school>
</period>
</studentcareer>

读取XML文件后组装成的数据格式:

读取XML文件
读取XML文件

下面的例子使用的数据、文件都是以上所列数据、文件,介绍各个方法时不再赘述,直接贴代码。

一、PHP字符串方式读写XML文件:

1. 字符串方式写XML文件:

<?php
/**
* function:使用字符串方式写XML文件
* author:JetWu
* date:2016.12.03
**/
$mysqli = mysqli_connect(‘localhost’, ‘root’, ‘123456’, ‘wjt’);
if(mysqli_connect_errno()) die(‘database connect fail:’ . mysqli_connect_error());

$sql = ‘select * from study order by starttime’;
$res = mysqli_query($mysqli, $sql);
$study = array();
while($row = mysqli_fetch_array($res)) {
$study[] = $row;
}
//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);

$str = “<studentcareer>\n”;
foreach($study as $v) {
$str .= “\t<period>\n”;
foreach($xmlTag as $x) {
$str .= “\t\t<“.$x.”>” . $v[$x] . “</”.$x.”>\n”;
}
$str .= “\t</period>\n”;
}
$str .= ‘</studentcareer>’;

$file = ‘./write_str.xml’;
file_put_contents($file, $str);

2. 字符串方式读XML文件:

<?php
/**
* function:使用字符串方式读XML文件
* author:JetWu
* date:2016.12.03
**/
$file = ‘./write_str.xml’;
$con = file_get_contents($file);

//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);

$arr = array();
foreach($xmlTag as $x) {
preg_match_all(“/<“.$x.”>.*<\/”.$x.”>/”, $con, $temp);
$arr[] = $temp[0];
}
//去除XML标签并组装数据
$data = array();
foreach($arr as $key => $value) {
foreach($value as $k => $v) {
$a = explode($xmlTag[$key].’>’, $v);
$v = substr($a[1], 0, strlen($a[1])-2);
$data[$k][$xmlTag[$key]] = $v;
}
}
echo ‘<pre>’;
print_r($data);

二、DOMDocument读写XML文件

1. DOMDocument写XML文件:

<?php
/**
* function:DOMDocument写XML文件
* author:JetWu
* date:2016.12.03
**/
$mysqli = mysqli_connect(‘localhost’, ‘root’, ‘123456’, ‘wjt’);
if(mysqli_connect_errno()) die(‘database connect fail:’ . mysqli_connect_error());

$sql = ‘select * from study order by starttime’;
$res = mysqli_query($mysqli, $sql);
$study = array();
while($row = mysqli_fetch_array($res)) {
$study[] = $row;
}
//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);

$dom = new DOMDocument(‘1.0’, ‘utf8’);
$dom->formatOutput = true;
$studentcareer = $dom->createElement(‘studentcareer’);
$dom->appendChild($studentcareer);
foreach($study as $s) {
$period = $dom->createElement(‘period’);
$studentcareer->appendChild($period);
foreach($xmlTag as $x) {
$element = $dom->createElement($x);
$period->appendChild($element);
$text = $dom->createTextNode($s[$x]);
$element->appendChild($text);
}
}
$dom->save(‘./write_dom.xml’);

2. DOMDocument读XML文件:

<?php
/**
* function:DOMDocument读XML文件
* author:JetWu
* date:2016.12.03
**/
//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);
$dom = new DOMDocument();
$dom->load(‘./write_dom.xml’);
$periods = $dom->getElementsByTagName(‘period’);
$study = array();
foreach($periods as $k => $p) {
foreach($xmlTag as $x) {
$node = $p->getElementsByTagName($x);
$study[$k][$x] = $node->item(0)->nodeValue;
}
}
echo ‘<pre>’;
print_r($study);

三、XMLWriter和XMLReader读写XML文件

1. XMLWriter写XML文件:

<?php
/**
* function:XMLWriter写XML文件
* author:JetWu
* date:2016.12.03
**/
$mysqli = mysqli_connect(‘localhost’, ‘root’, ‘123456’, ‘wjt’);
if(mysqli_connect_errno()) die(‘database connect fail:’ . mysqli_connect_error());

$sql = ‘select * from study order by starttime’;
$res = mysqli_query($mysqli, $sql);
$study = array();
while($row = mysqli_fetch_array($res)) {
$study[] = $row;
}

//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);

$xml = new XMLWriter();
$xml->openUri(‘./write_WR.xml’);
$xml->setIndentString(‘ ‘);//设置缩进格式化使用的符号
$xml->setIndent(true);
$xml->startDocument(‘1.0’, ‘utf8’);
$xml->startElement(‘studentcareer’);
foreach($study as $s) {
$xml->startElement(‘period’);
foreach($xmlTag as $x) {
$xml->startElement($x);
$xml->text($s[$x]);
$xml->endElement();
}
$xml->endElement();
}
$xml->endElement();
$xml->endDocument();
$xml->flush();

2. XMLReader读XML文件:

<?php
/**
* function:XMLReader读XML文件
* author:JetWu
* date:2016.12.03
**/
//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);
$xml = new XMLReader();
$xml->open(‘./write_WR.xml’);
$study = array();
$count = 0;//记录数:方便组装数据
$name = ”;
while($xml->read()) {
$n = $xml->name;
if($xml->nodeType == XMLReader::ELEMENT) {
if($n == ‘period’) {//开始下一条记录的读取
$count ++;
} else if(in_array($n, $xmlTag)) {//记录需要获取文本值的标签名
$name = $n;
}
} else if($xml->nodeType == XMLReader::TEXT) {
if(in_array($name, $xmlTag)) {
$study[$count][$name] = $xml->value;
}
}
}
$xml->close();
echo ‘<pre>’;
print_r($study);

四、SimpleXML读写XML文件

1. SimpleXML写XML文件:

<?php
/**
* function:SimpleXML写XML文件
* author:JetWu
* date:2016.12.03
**/
$mysqli = mysqli_connect(‘localhost’, ‘root’, ‘123456’, ‘wjt’);
if(mysqli_connect_errno()) die(‘database connect fail:’ . mysqli_connect_error());

$sql = ‘select * from study order by starttime’;
$res = mysqli_query($mysqli, $sql);
$study = array();
while($row = mysqli_fetch_array($res)) {
$study[] = $row;
}

//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);
$xml = new SimpleXMLElement(‘<?xml version=”1.0″ encoding=”UTF-8″?><studentcareer />’);
foreach($study as $s) {
$period = $xml->addChild(‘period’);
foreach($xmlTag as $x) {
$period->addChild($x, $s[$x]);
}
}
$xml->asXml(‘./write_sim.xml’);//输出XML文件(没有格式化)

2. SimpleXML读XML文件:

<?php
/**
* function:SimpleXML读XML文件
* author:JetWu
* date:2016.12.03
**/
//XML标签配置
$xmlTag = array(
‘starttime’,
‘endtime’,
‘school’
);
$study = array();
$xml = simplexml_load_file(‘./write_sim.xml’);
foreach($xml->children() as $period) {
$study[] = get_object_vars($period);//获取对象全部属性,返回数组
}
echo ‘<pre>’;
print_r($study);

总结:这四种方法中,字符串的方式是最原始的方法。SimpleXML和DOM扩展是属于基于树的解析器,把整个文档存储为树的数据结构中,需要把整个文档都加载到内存中才能工作,所以当处理大型XML文档的时候,性能会剧减。XMLReader则是属于基于流的解析器,它不会一次把整个文档加载到内存中,而是每次分别读取其中的一个节点并允许实时与之交互,这种方式效率高,而且占内存少。

原文地址:https://www.cnblogs.com/wujuntian/p/6128297.html

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