遇到一种xml格式的excel文件，格式大概如下：
XML code:
<?xml version="1.0"?>
<?mso-application progid="Excel.Sheet"?>
<Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet"
xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:x="urn:schemas-microsoft-com:office:excel"
xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet"
xmlns:html="http://www.w3.org/TR/REC-html40">
<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office">
<Created>2009-12-18T14:44:09Z</Created>
<Version>12.00</Version>
</DocumentProperties>
<ExcelWorkbook xmlns="urn:schemas-microsoft-com:office:excel">
<WindowHeight>10005</WindowHeight>
<WindowWidth>10005</WindowWidth>
<WindowTopX>120</WindowTopX>
<WindowTopY>135</WindowTopY>
<ProtectStructure>False</ProtectStructure>
<ProtectWindows>False</ProtectWindows>
</ExcelWorkbook>
<Styles>
<Style ss:ID="Default" ss:Name="Normal">
<Alignment ss:Vertical="Center"/>
<Font ss:FontName="Verdana" x:Family="Swiss"/>
</Style>
<Style ss:ID="s6
