XML文件要有根标签（Extra content at the end of the document in file 错误）

使用的xml文档如下

[html]  view plain  copy  

1. <?xml version="1.0" encoding="UTF-8"?>  
2.   <SearchConstraints>  
3.     <Begin>glucose</Begin>  
4.     <End>Ethanol</End>  
5.     <Interface>name</Interface>  
6.     <IntermediatesInclude number="0"></IntermediatesInclude>  
7.     <IntermediatesExclude> number="0"></IntermediatesExclude>  
8.     <Organisms type="all"></Organisms>  
9.     <KShort>10</KShort>  
10.   </SearchConstraints>  
11.   <StoPList>  
12.     <StoP>  
13.       <Source id="glucose"></Source>  
14.       <Target id="Ethanol"></Target>  
15.       <RouteList>  
16.       </RouteList>  
17.     </StoP>  
18.   </StoPList>  

问题所在：没有加根标签呀！XML文件只能有一个根标签！

把xml改成下面这样就ok了，也就是加一个Document标签，将先前的两个根标签SearchConstraints和StoPList都放到Document标签的下面，从而整个XML文件只有一个根标签。

[html]  view plain  copy  

1. <?xml version="1.0" encoding="UTF-8"?>  
2. <Document>  
3.   <SearchConstraints>  
4.     <Begin>glucose</Begin>  
5.     <End>Ethanol</End>  
6.     <Interface>name</Interface>  
7.     <IntermediatesInclude number="0"></IntermediatesInclude>  
8.     <IntermediatesExclude> number="0"></IntermediatesExclude>  
9.     <Organisms type="all"></Organisms>  
10.     <KShort>10</KShort>  
11.   </SearchConstraints>  
12.   <StoPList>  
13.     <StoP>  
14.       <Source id="glucose"></Source>  
15.       <Target id="Ethanol"></Target>  
16.       <RouteList>  
17.       </RouteList>  
18.     </StoP>  
19.   </StoPList>  
20. </Document>