嵌套元素的XML映射属性

Question

我正在使用XStream,我有一个XML示例:

<person>
    <firstname>Joe</firstname>
    <lastname>Walnes</lastname>
    <phone value="1234-456" />
    <fax value="9999-999" />
</person>

我想把它映射到课堂上

public class Person {

    private String firstname;
    private String lastname;
    private String phone;
    private String fax;

}

因此,我们的想法是将嵌套元素的属性映射到当前对象.我试图找到任何即用型转换器但没有成功.我相信通过实施新的转换器是可能的,但也许有人已经这样做了.或者有一个我没有找到的解决方案.

更新:

我想要实现的想法是省略不必要的创建和映射实体.我根本不需要电话和传真实体,我只需要在我的模型中使用它们的属性.我试图解析的XML模式对我来说是第三方,我无法改变它.

Answer 1

我不知道一个即将使用的转换器会做到这一点,但写一个很简单

import com.thoughtworks.xstream.converters.*;
import com.thoughtworks.xstream.io.*;

public class ValueAttributeConverter implements Converter {
  public boolean canConvert(Class cls) {
    return (cls == String.class);
  }

  public void marshal(Object source, HierarchicalStreamWriter w, MarshallingContext ctx) {
    w.addAttribute("value", (String)source);
  }

  public Object unmarshal(HierarchicalStreamReader r, UnmarshallingContext ctx) {
    return r.getAttribute("value");
  }
}

您可以使用注释将转换器附加到相关字段

import com.thoughtworks.xstream.annotations.*;

@XStreamAlias("person")
public class Person {

    private String firstname;
    private String lastname;

    @XStreamConverter(ValueAttributeConverter.class)
    private String phone;

    @XStreamConverter(ValueAttributeConverter.class)
    private String fax;

    // add appropriate constructor(s)

    /** For testing purposes - not required by XStream itself */
    public String toString() {
      return "fn: " + firstname + ", ln: " + lastname +
             ", p: " + phone + ", f: " + fax;
    }
}

要使这项工作,您需要做的就是指示XStream读取注释:

XStream xs = new XStream();
xs.processAnnotations(Person.class);
Person p = (Person)xs.fromXML(
  "<person>\n" +
  "  <firstname>Joe</firstname>\n" +
  "  <lastname>Walnes</lastname>\n" +
  "  <phone value='1234-456' />\n" +
  "  <fax value='9999-999' />\n" +
  "</person>");
System.out.println(p);
// prints fn: Joe, ln: Walnes, p: 1234-456, f: 9999-999