我如何使用 XStream 为简单地图生成较小的输出？

发布于 2025-01-04 02:50:17 字数 1528 浏览 1 评论 0原文

我使用 xstream 序列化应用程序的数据。由于它应该由其他应用程序读取 - 甚至手动查看，所以我想修改 XML。

我有非常简单类型的大地图，例如 TreeMap 和 TreeMap。我想让我的输出更加紧凑。说从：

<entry>
    <int>56</int>
    <double>38.0</double>
</entry>

到 38.0

不幸的是我使用 this.aliasAttribute(Entry.class, "key", "key") 进行的实验 因空指针异常而失败。

我无法理解如何编写/注册一个 Converter 来处理 TreeMap 但保留 TreeMap的默认行为对象，MyComplexObject> 。

也许你可以给我一个解决方案，谢谢。

也许堆栈跟踪可以提供一些信息。

java.lang.NullPointerException
    at com.thoughtworks.xstream.converters.reflection.FieldDictionary.buildMap(FieldDictionary.java:128)
    at com.thoughtworks.xstream.converters.reflection.FieldDictionary.fieldOrNull(FieldDictionary.java:113)
    at com.thoughtworks.xstream.converters.reflection.FieldDictionary.field(FieldDictionary.java:92)
    at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.getField(PureJavaReflectionProvider.java:181)
    at com.thoughtworks.xstream.mapper.AttributeMapper.addAttributeFor(AttributeMapper.java:169)
    at com.thoughtworks.xstream.XStream.useAttributeFor(XStream.java:1226)
    at com.thoughtworks.xstream.XStream.aliasAttribute(XStream.java:1192)
    at myproject.XstreamSerializer.<init>(XstreamSerializer.java:43)

原文

I serialize the data of my application with xstream. Since it should be read by other applications - or even viewed manuall I'd like to touch up the XML.

I have big maps of very simple types like TreeMap<Integer,Double> and TreeMap<String,Double>. I want to make my output more compact for these. Say from:

<entry>
    <int>56</int>
    <double>38.0</double>
</entry>

to <entry key="56">38.0</entry>

Unfortunately my experiments using this.aliasAttribute(Entry.class, "key", "key") fail with null pointer exception.

And I'm having problems to understand how I would write/register an Converter that would handle TreeMap<Integer,Double> but keeps the default behaviour for TreeMap<Object,MyComplexObject> .

Maybe you can point me to a solution, thanks.

maybe the stacktrace can give some information.

java.lang.NullPointerException
    at com.thoughtworks.xstream.converters.reflection.FieldDictionary.buildMap(FieldDictionary.java:128)
    at com.thoughtworks.xstream.converters.reflection.FieldDictionary.fieldOrNull(FieldDictionary.java:113)
    at com.thoughtworks.xstream.converters.reflection.FieldDictionary.field(FieldDictionary.java:92)
    at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.getField(PureJavaReflectionProvider.java:181)
    at com.thoughtworks.xstream.mapper.AttributeMapper.addAttributeFor(AttributeMapper.java:169)
    at com.thoughtworks.xstream.XStream.useAttributeFor(XStream.java:1226)
    at com.thoughtworks.xstream.XStream.aliasAttribute(XStream.java:1192)
    at myproject.XstreamSerializer.<init>(XstreamSerializer.java:43)

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