这些问题是我在实际工作中遇到的,遇到一个问题就记一个问题,因为我这人脑子不太好,过段时间就会想不起来怎么解决了。
(一) 类的继承关系,在转化为xml时,父类节点应添加class属性,指明当前是哪个子类继承了它,否则在由xml转化为Object时会出错,因为XStream并不知道该把当前节点实例化为哪种类型。
(1)一个抽象类 Animal.java
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedBlockStart.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
(2) Pig继承自Animal
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedBlockStart.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/InBlock.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedBlockEnd.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
(3) AnimalContor类中包含Animal类型的变量
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedBlockStart.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/InBlock.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/InBlock.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedSubBlockStart.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/InBlock.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedSubBlockEnd.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedSubBlockStart.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/InBlock.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedSubBlockStart.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedSubBlockStart.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/ExpandedBlockEnd.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
(4) 将AnimalContor对象转化为xml
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
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![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
输出:
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
注意,animal节点有class属性,表明当前类由哪个子类来实现
(5) 将xml转化为AnimalContor对象
animal节点有class属性
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
输出:0002
animal节点没有class属性,会抛出异常
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
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抛出如下异常:
java.lang.InstantiationError: xml_chb.Animal
at sun.reflect.GeneratedSerializationConstructorAccessor3.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
at com.thoughtworks.xstream.converters.reflection.Sun14ReflectionProvider.newInstance(Sun14ReflectionProvider.java:54)
at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.instantiateNewInstance(AbstractReflectionConverter.java:223)
at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshal(AbstractReflectionConverter.java:117)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:56)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:45)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:46)
at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshallField(AbstractReflectionConverter.java:182)
at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.doUnmarshal(AbstractReflectionConverter.java:159)
at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshal(AbstractReflectionConverter.java:118)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:56)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:45)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:46)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:117)
at com.thoughtworks.xstream.core.ReferenceByXPathMarshallingStrategy.unmarshal(ReferenceByXPathMarshallingStrategy.java:29)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:826)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:813)
at com.thoughtworks.xstream.XStream.fromXML(XStream.java:761)
at com.thoughtworks.xstream.XStream.fromXML(XStream.java:753)
at xml_chb.AnimalContor.main(AnimalContor.java:41)
Exception in thread "main"