simplexml学习

user.xml文件路径："./model/user.xml"

如何调用xml:

1 header("Content-type: text/html; charset=utf-8"); 
2 $str=simplexml_load_file("./model/user.xml");

像空文件写入xml内容：

header ( "Content-Type:text/html;charset=utf-8" );
$string = <<<XML
<a>
 <b>
  <c>text</c>
  <c>stuff</c>
 </b>
 <d>
  <c>code</c>
 </d>
</a>
XML;

$xml = new SimpleXMLElement ( $string );
if ($xml->asXML ( 'user.xml' )) {
    echo "成功写入xml文件";
}
else{
    echo "未写入成功";
}

如何更改属性值：

注意一定要让文件有读写权限，不然 asXML() 无法写入值

 $str->name="鬼泣";
 $str->age="14";
 $str->asXML("./model/user.xml")

 

user.xml文件结构：

<?xml version="1.0"?>
<root>
    <user>
        <username>
             xyt
        </username>
        <password>
            123
        </password>
    </user>
        <user>
        <username>
             lzj
        </username>
        <password>
            1111
        </password>
    </user>
</root>

读取用户名和密码

<?php
header ( "Content-Type:text/html;charset=utf-8" );
$xml=simplexml_load_file("./model/user.xml");

$_user=$xml->xpath("/root/user");
$user=array();


while(list(,$node)=each($_user)){
    $a=array(trim($node->username    ->__toString()),trim($node->password->__toString()));
    $user[]=$a;
}

print_r($user);
?>

 Array (

[0] => Array ( [0] => xyt [1] => 123 )

[1] => Array ( [0] => lzj [1] => 1111 )

)

增加用户名和密码：

header ( "Content-Type:text/html;charset=utf-8" );
$xml = simplexml_load_file ( "./model/user.xml" );

$_user = $xml->xpath ( "/root/user" );
function insertintoxml($username, $password, $xml, $url = "./model/user.xml") {
    try {
        $strname = $xml->xpath ( "/root/user/username" );
        print_r ( $strname );
        
        // 不能存在相同的用户名：
        foreach ( $strname as $key => $value ) {
            if ($username == trim ( $value )) {            
                throw new Exception("Sorry,name was used!");
            }    
        }
        
             $length=count($xml->user);
             //添加一个子节点 user;
             $xml->addChild("user","");
             $xml->user[$length]->addChild("username",$username);
             $xml->user[$length]->addChild("password",$password);
        if (! $xml->asxml ( $url )) {
            throw new Exception("failed,make you configfile rewriteable!");        
        }
        return true;
    } catch ( Exception $e ) {
        echo $e->getMessage();
    }
}

if (insertintoxml ( "xyt", "asdfads", $xml )) {
    echo "插入成功！";
}

删除用户名和密码：

function deletefrom($username, $xml, $url = "./model/user.xml") {
    try {
        
        $strname = $xml->xpath ( "/root/user/username" );
        foreach ( $strname as $key => $value ) {
            if (trim($value) == $username){
                unset ( $xml->user [$key] );            
            }
        }
        

        if (! $xml->asXML ( $url )) {
            throw new Exception ( "failed,make you configfile rewriteable!" );
        }
        return true;
    } catch ( Exception $e ) {
        echo $e->getMessage ();
    }
}
//   insertintoxml("1", "asdf", $xml);
//   insertintoxml("2", "asdf", $xml);
//   insertintoxml("3", "asdf", $xml);
//   insertintoxml("4", "asdf", $xml);
//   insertintoxml("5", "asdf", $xml);
(deletefrom ( "4", $xml ));

整体代码：

<?php
header ( "Content-Type:text/html;charset=utf-8" );
$xml = simplexml_load_file ( "./model/user.xml" );

$_user = $xml->xpath ( "/root/user" );
function insertintoxml($username, $password, $xml, $url = "./model/user.xml") {
    try {
        $strname = $xml->xpath ( "/root/user/username" );
        
        // 不能存在相同的用户名：
        foreach ( $strname as $key => $value ) {
            if ($username == trim ( $value )) {
                throw new Exception ( "Sorry,name was used!" );
            }
        }
        
        $length = count ( $xml->user );
        // 添加一个子节点 user;
        $xml->addChild ( "user", "" );
        $xml->user [$length]->addChild ( "username", $username );
        $xml->user [$length]->addChild ( "password", $password );
        if (! $xml->asXML ( $url )) {
            throw new Exception ( "failed,make you configfile rewriteable!" );
        }
        return true;
    } catch ( Exception $e ) {
        echo $e->getMessage ();
    }
}
function deletefrom($username, $xml, $url = "./model/user.xml") {
    try {
        
        $strname = $xml->xpath ( "/root/user/username" );
        foreach ( $strname as $key => $value ) {
            if (trim($value) == $username){
                unset ( $xml->user [$key] );            
            }
        }
        

        if (! $xml->asXML ( $url )) {
            throw new Exception ( "failed,make you configfile rewriteable!" );
        }
        return true;
    } catch ( Exception $e ) {
        echo $e->getMessage ();
    }
}
//   insertintoxml("1", "asdf", $xml);
//   insertintoxml("2", "asdf", $xml);
//   insertintoxml("3", "asdf", $xml);
//   insertintoxml("4", "asdf", $xml);
//   insertintoxml("5", "asdf", $xml);
(deletefrom ( "4", $xml ));

?>

总结：

$xml=$strname = $xml->xpath ( "//username" ); //两反斜杠代表所有深度。

simplexml简单实用。