How to read list elements with attribute via XStream

问题

I'm using XStream to read below example xml file.

<list>
    <file>/setup/x86-linux2/bin/zip.txt</file>
    <file type="dir">/src/bin/</file>
    <name>test xml</name>
</list>

Below is my code for reading above xml,

public class ListWithConverter {

    public static class FileConvertor implements Converter {
        public boolean canConvert(final Class clazz) {
            return clazz.equals(MyFile.class);
        }

        public void marshal(Object source, HierarchicalStreamWriter writer,
                MarshallingContext context) {
            throw new UnsupportedOperationException("Not supported to write file element yet."); //$NON-NLS-1$
        }

        public Object unmarshal(HierarchicalStreamReader reader,
                UnmarshallingContext context) {
            MyFile file = new MyFile();
            for (Iterator<String> iter = reader.getAttributeNames(); iter.hasNext(); ){
                String name = iter.next();
                if (name.equals("type")) //$NON-NLS-1$
                    file.type = reader.getAttribute(name);
            }
            file.path = reader.getValue();
            return file;
        }
    }

    @XStreamAlias("list")
    public class MyList {
        @XStreamAlias("name")
        String name;
        @XStreamImplicit(itemFieldName="file")  @XStreamConverter(FileConvertor.class)
        List<MyFile> files;
    }

    public static class MyFile {
        String type;
        String path;
    }

    public static void main(String[] args) throws MalformedURLException, IOException {
        XStream xstream = new XStream();
        xstream.setClassLoader(MyList.class.getClassLoader());
        xstream.processAnnotations(MyList.class);
        InputStream stream = new File("test.xml").toURL().openStream();
        MyList list = (MyList)xstream.fromXML(stream);
        System.out.println(list.name);
        for (MyFile f : list.files) {
            System.out.println(f.path);
        }
    }
}

The output of my program is,

test xml
null
null

Looks like XStream does not support using annotation '@XStreamImplicit' and '@XStreamConverter' at the same time.

My question is how should I do to read the example xml via XStream?

回答1:

I found a solution after migrating to XStream 1.4.x,

@XStreamAlias("list")
public class MyList {
    @XStreamAlias("name")
    String name;
    @XStreamImplicit(itemFieldName="file")
    List<MyFile> files;
}

@XStreamAlias("file")
@XStreamConverter(value=ToAttributedValueConverter.class, strings={"path"})
public static class MyFile {
    @XStreamAlias("type")
    @XStreamAsAttribute
    String type;

    String path;
}

来源：https://stackoverflow.com/questions/16460810/how-to-read-list-elements-with-attribute-via-xstream

标签

java

xml

xml-parsing

xstream