XmlReader對象是空

Question

我使用的XMLReader來讀取XML文件

以下是從XML文件中的代碼：

<?xml version="1.0"?> 
<catalog> 
    <book id="bk101"> 
     <author>Gambardella, Matthew</author> 
     <title>XML Developer's Guide</title> 
     <genre>Computer</genre> 
     <price>44.95</price> 
     <publish_date>2000-10-01</publish_date> 
     <description>An in-depth look at creating applications 
     with XML.</description> 
    </book> 
    <book id="bk102"> 
     <author>Ralls, Kim</author> 
     <title>Midnight Rain</title> 
     <genre>Fantasy</genre> 
     <price>5.95</price> 
     <publish_date>2000-12-16</publish_date> 
     <description>A former architect battles corporate zombies, 
     an evil sorceress, and her own childhood to become queen 
     of the world.</description> 
    </book> 
    <book id="bk103"> 
     <author>Corets, Eva</author> 
     <title>Maeve Ascendant</title> 
     <genre>Fantasy</genre> 
     <price>5.95</price> 
     <publish_date>2000-11-17</publish_date> 
     <description>After the collapse of a nanotechnology 
     society in England, the young survivors lay the 
     foundation for a new society.</description> 
    </book> 
    <book id="bk104"> 
     <author>Corets, Eva</author> 
     <title>Oberon's Legacy</title> 
     <genre>Fantasy</genre> 
     <price>5.95</price> 
     <publish_date>2001-03-10</publish_date> 
     <description>In post-apocalypse England, the mysterious 
     agent known only as Oberon helps to create a new life 
     for the inhabitants of London. Sequel to Maeve 
     Ascendant.</description> 
    </book> 
    <book id="bk105"> 
     <author>Corets, Eva</author> 
     <title>The Sundered Grail</title> 
     <genre>Fantasy</genre> 
     <price>5.95</price> 
     <publish_date>2001-09-10</publish_date> 
     <description>The two daughters of Maeve, half-sisters, 
     battle one another for control of England. Sequel to 
     Oberon's Legacy.</description> 
    </book> 
    <book id="bk106"> 
     <author>Randall, Cynthia</author> 
     <title>Lover Birds</title> 
     <genre>Romance</genre> 
     <price>4.95</price> 
     <publish_date>2000-09-02</publish_date> 
     <description>When Carla meets Paul at an ornithology 
     conference, tempers fly as feathers get ruffled.</description> 
    </book> 
    <book id="bk107"> 
     <author>Thurman, Paula</author> 
     <title>Splish Splash</title> 
     <genre>Romance</genre> 
     <price>4.95</price> 
     <publish_date>2000-11-02</publish_date> 
     <description>A deep sea diver finds true love twenty 
     thousand leagues beneath the sea.</description> 
    </book> 
    <book id="bk108"> 
     <author>Knorr, Stefan</author> 
     <title>Creepy Crawlies</title> 
     <genre>Horror</genre> 
     <price>4.95</price> 
     <publish_date>2000-12-06</publish_date> 
     <description>An anthology of horror stories about roaches, 
     centipedes, scorpions and other insects.</description> 
    </book> 
    <book id="bk109"> 
     <author>Kress, Peter</author> 
     <title>Paradox Lost</title> 
     <genre>Science Fiction</genre> 
     <price>6.95</price> 
     <publish_date>2000-11-02</publish_date> 
     <description>After an inadvertant trip through a Heisenberg 
     Uncertainty Device, James Salway discovers the problems 
     of being quantum.</description> 
    </book> 
    <book id="bk110"> 
     <author>O'Brien, Tim</author> 
     <title>Microsoft .NET: The Programming Bible</title> 
     <genre>Computer</genre> 
     <price>36.95</price> 
     <publish_date>2000-12-09</publish_date> 
     <description>Microsoft's .NET initiative is explored in 
     detail in this deep programmer's reference.</description> 
    </book> 
    <book id="bk111"> 
     <author>O'Brien, Tim</author> 
     <title>MSXML3: A Comprehensive Guide</title> 
     <genre>Computer</genre> 
     <price>36.95</price> 
     <publish_date>2000-12-01</publish_date> 
     <description>The Microsoft MSXML3 parser is covered in 
     detail, with attention to XML DOM interfaces, XSLT processing, 
     SAX and more.</description> 
    </book> 
    <book id="bk112"> 
     <author>Galos, Mike</author> 
     <title>Visual Studio 7: A Comprehensive Guide</title> 
     <genre>Computer</genre> 
     <price>49.95</price> 
     <publish_date>2001-04-16</publish_date> 
     <description>Microsoft Visual Studio 7 is explored in depth, 
     looking at how Visual Basic, Visual C++, C#, and ASP+ are 
     integrated into a comprehensive development 
     environment.</description> 
    </book> 
</catalog> 

現在，當我使用下面的PHP代碼從XML閱讀：

$reader = new XMLReader(); 
$reader->open('/var/www/myhost/htdocs/books.xml'); 

while ($reader->read()) { 
    print_r($reader); 
} 

輸出配備，如：

XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () 
XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () 
XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () 
XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () 
XMLReader Object () XMLReader Object () XMLReader Object () XMLReader Object () 

我的問題是，

1. 爲什麼Object是空的？
2. 如何訪問數據？

Answer 1

從manual，你可以

• 訪問值做：$閱讀器 - >值;
• 使用$ reader-> getAttribute（'attributename'）訪問屬性;
• 檢查當前節點的屬性是否爲$ reader-> hasAttributes; （這是一個布爾值）

等等

考慮$讀者在你的XML光標。