使用Simple XML（org.simpleframework.xml）序列化第三方类 [英] Serialization third-party classes with Simple XML (org.simpleframework.xml)

问题描述

我决定使用简单XML序列化，并且遇到了基本问题。我试图将 java.util.UUID 类实例序列化为这个小类中的最后一个字段：

I have decided to use Simple XML serialization and was stucked with basic problem. I am trying to serialize java.util.UUID class instance as final field in this small class:

@Root
public class Identity {
    @Attribute
    private final UUID id;

    public Identity(@Attribute UUID id) {
        this.id = id;
    } 
}

教程显示了如何通过注册这样的转换器来序列化第三方对象：

Tutorial shows how to serialize third-party objects by registering converters like this:

Registry registry = new Registry();
registry.bind(UUID.class, UUIDConverter.class);
Strategy strategy = new RegistryStrategy(registry);
Serializer serializer = new Persister(strategy);

serializer.write( object, stream );

适用于UUID的转换器非常简单：

appropriate converter for UUID is pretty simple:

public class UUIDConverter implements Converter<UUID> {
    @Override
    public UUID read(InputNode node) throws Exception {
       return new UUID.fromString(node.getValue());
    }
    @Override
    public void write(OutputNode node, UUID value) throws Exception {
       node.setValue(value.toString());
    }
}

但是这个简单的代码对我来说不起作用，在序列化期间，具有UUID字段的对象被抛出异常不支持类java.util.UUID的变换。

But this simple code just didn't work for me, during serialization objects with UUID fields was thrown exception Transform of class java.util.UUID not supported.

我尝试了类似的东西自定义匹配器（不在教程中）对我有用：

I have tried something something similar with custom Matcher (which was not in tutorial) that works for me:

Serializer serializer = new Persister(new MyMatcher());

serializer.write( object, stream );

和 Matcher 类看起来像这样： / p>

and Matcher class looks like this:

public static class MyMatcher implements Matcher {
    @Override
    @SuppressWarnings("unchecked")
    public Transform match(Class type) throws Exception {
        if (type.equals(UUID.class))
            return new UUIDTransform();
        return null;
    }
}

public class UUIDTransform implements Transform<UUID> {
    @Override
    public UUID read(String value) throws Exception {
        return UUID.fromString(value);
    }
    @Override
    public String write(UUID value) throws Exception {
        return value.toString();
    }
}

问题：

• 自定义匹配器总是推荐用于流式传输第三方类吗？


• 在哪种情况下我可以使用Converter？


• 有没有更好的Simple XML教程/示例？

谢谢。

推荐答案

我必须自己回答再次： - ）

I have to answer by myself again :-)

来自支持列表的Simple XML项目负责人Niall Gallagher的建议：

Advice from Niall Gallagher, project leader of Simple XML, from support-list:

你可以使用转换器或转换器。我会说UUID为
带有匹配器的转换将是最简单的选择。

"You could use either a Converter or a Transform. I would say for a UUID a Transform with a Matcher would be the easiest option."

所以，我使用转换< T> / 匹配器和对此感到满意。这并没有改变转换器< T> 对我不起作用的事实： - ）

So, I use Transform<T>/Matcher and satisfied with it. This does not alter the fact that the Converter<T> does not work for me :-)

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