Question

我正在使用ToAttributedValueConverter通过类注释：

@XStreamConverter(value = ToAttributedValueConverter.class, strings = { "text" })
public final class Message {
    private final String text;

    // Needed for XStream serialization
    @SuppressWarnings("unused")
    private Message() {
        text = null;
    }

    public Message(final String text) {
        if (text == null) {
            throw new NullPointerException();
        }
        this.text = text;
    }

    public String getText() {
        return this.text;
    }
}

示例：

final XStream xstream = new XStream();
xstream.alias("message", Message.class);
xstream.processAnnotations(Message.class);

final Message message = new Message("Lorem Ipsum");
final String xml = xstream.toXML(message);
System.out.println(xml);

输出结果为：

<message>Lorem Ipsum</message>

为了将数据模型（类Message）与持久性（XStream）分开，我将从数据模型中删除所有XStream注释。

例如，XStreamAlias("message")可以简单地替换为xstream.alias("message", Message.class)。但是在xstream对象中替换ToAttributedValueConverter是什么？

Answer 1

有时答案很简单。简短的回答是：使用xstream.registerConverter(converter)

答案很长： ToAttributeValueConverter是转换器。也就是说，您可以使用XStream实例注册该实例以影响序列化。

以下代码将在您的问题中执行您想要的操作，而不使用XStream批注（我将Message类用于该示例）。所有相关代码均采用main方法：

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.extended.ToAttributedValueConverter;

public class XmlSample {

    public static void main(String[] args) {
        XStream xStream = new XStream();
        Converter converter = new ToAttributedValueConverter(Message.class,
                xStream.getMapper(), xStream.getReflectionProvider(), xStream.getConverterLookup(), "text");
        xStream.registerConverter(converter);
        xStream.alias("message", Message.class);
        System.out.println(xStream.toXML(new Message("testtest")));
    }

    public static final class Message {
        private final String text;

        // Needed for XStream serialization
        @SuppressWarnings("unused")
        private Message() {
            text = null;
        }

        public Message(final String text) {
            if (text == null) {
                throw new NullPointerException();
            }
            this.text = text;
        }

        public String getText() {
            return this.text;
        }
    }
}

替换XStream对象中的ToAttributedValueConverter

1 个答案: