Java XStream在普通xml上失败

我有一个非常简单的xml文件：

testSimple2.txt

<root>
  <document>
  </document>
</root>

Main.java

@XStreamAlias("root")
public class Root {

 @XStreamAlias("document")
 static public class Document {
 }
 @XStreamAlias("document")
 Document document;

}

主要代码：

XStream xstream = new XStream();
xstream.autodetectAnnotations(true);
xstream.processAnnotations(Root.class);
Root newJoe = (Root) xstream.fromXML(new File("testSimple2.txt"), Root.class); //Exception here

将引发以下异常

com.thoughtworks.xstream.converters.ConversionException: Element document of type verySimple.Root$Document is not defined as field in type java.lang.Class
---- Debugging information ----
class               : verySimple.Root
required-type       : verySimple.Root
converter-type      : com.thoughtworks.xstream.converters.reflection.ReflectionConverter
path                : /root/document
line number         : 3
version             : null
-------------------------------
    at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.writeValueToImplicitCollection(AbstractReflectionConverter.java:403)
    at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.doUnmarshal(AbstractReflectionConverter.java:334)
    at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshal(AbstractReflectionConverter.java:234)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)
    at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:65)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:66)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:50)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:134)
    at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:32)
    at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:1058)
    at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:1042)
    at com.thoughtworks.xstream.XStream.fromXML(XStream.java:1006)
    at verySimple.RootProcess.main(RootProcess.java:26)

---

我知道肯定有一些简单的错误，但我看不出来。请提供帮助。

可能是您缺少xml标题行：

<?xml version="1.0" encoding="utf-8"?>
<root>
  <document>
  </document>
</root>

---

但我知道XStream不应该需要它。

我不敢相信我犯了这个错误。在第四行：

Root newJoe = (Root) xstream.fromXML(new File("testSimple2.txt"));

---

我所需要的只是删除“Root.class”，或者用实例替换它。在谷歌搜索和发布此类问题之前检查方法签名和文档还有一个原因…

通常有两个

@XStreamAlias（“文档”）

注释吗？