php如何修改xml内容

例如：

example.xml

<?xml version="1.0" encoding="utf-8"?><root>
    <book id="1">
        <title>title1</title>
    </book>
    <book id="2">
        <title>title2</title>
    </book>
    <book id="3">
        <title>title3</title>
    </book>
    <book id="4">
        <title>title4</title>
    </book>
    <book id="5">
        <title>title5</title>
    </book></root>

首先遍历一下该xml文档

<?php

    $doc = new DOMDocument();    $doc->load('example.xml');    $books = $doc -> getElementsByTagName("book");    //遍历
    foreach ($books as $book) {        echo $book->getAttribute('id')."-";        echo $book->getElementsByTagName("title")->item(0)->nodeValue;        echo "<br>";
    }

运行结果为：

1-title1
2-title2
3-title3
4-title4
5-title5

修改：

<?php    $doc = new DOMDocument();    $doc->load('example.xml');    $books = $doc -> getElementsByTagName("book");    //遍历
    foreach ($books as $book) {        //将id=3的title设置为33333
        if($book->getAttribute('id')==3){
            echo $book->getAttribute('id')."-";
            echo $book->getElementsByTagName("title")->item(0)->nodeValue="33333";
            echo "<br>";
        }
    }    //对文件做修改后，一定要记得重新sava一下，才能修改掉原文件
    $doc -> save('example.xml');

修改之后为：

<?xml version="1.0" encoding="utf-8"?><root>
    <book id="1">
        <title>title1</title>
    </book>
    <book id="2">
        <title>title2</title>
    </book>
    <book id="3">
        <title>33333</title>
    </book>
    <book id="4">
        <title>title4</title>
    </book>
    <book id="5">
        <title>title5</title>
    </book></root>

删除操作：

<?php    $doc = new DOMDocument();    $doc->load('example.xml');    $root = $doc -> documentElement;//根标签   
    $books = $doc -> getElementsByTagName("book");    //遍历
    foreach ($books as $book) {        //将id=4的删除
        if($book->getAttribute('id')==4){            $root->removeChild($book);
        }
    }    //对文件做修改后，一定要记得重新sava一下，才能修改掉原文件
    $doc -> save('example.xml');

删除后的结果为：

<?xml version="1.0" encoding="utf-8"?><root>
    <book id="1">
        <title>title1</title>
    </book>
    <book id="2">
        <title>title2</title>
    </book>
    <book id="3">
        <title>33333</title>
    </book>

    <book id="5">
        <title>title5</title>
    </book></root>