用什么方法把下面一段xml 里FieldName属性读出来
<BookMapping xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" BookName="ServiceRewards" DatabaseName="CDIPOptimizationSample">
<SheetMappingList>
<SheetMapping SheetName="数据表单" TableName="table1" SampleRows="0">
<CloumnMappingList>
<CloumnMapping CloumnName="单板名称" FieldName="ProjectName" AllowNull="true" />
<CloumnMapping CloumnName="所在产品" FieldName="PrintVersion" AllowNull="true" />
<CloumnMapping CloumnName="开发代表(RDPDT)" FieldName="RDPDT" AllowNull="true" />
<CloumnMapping CloumnName="HQA" FieldName="HQA" AllowNull="true" />
<CloumnMapping CloumnName="绝对规模(初始估计)" FieldName="pla-ext01" AllowNull="true" />
<CloumnMapping CloumnName="等效新增规模(初始估计)" FieldName="Npla-ext02" AllowNull="true" />
</CloumnMappingList>
</SheetMapping>
</SheetMappingList>
</BookMapping>
暮色呼如