在不进行包装类的情况下，如何封送Jaxb元素列表？

Question

没有实际组成一个编写器并将每个元素附加到字符串上。有没有一种方法可以让JAXB编组器编组对象列表，而我可以在上面给出顶层元素的名称？

我觉得我已经很接近了

//http://blog.bdoughan.com/2012/07/jaxb-no-annotations-required.html
public <T> String jaxb(Collection<T> o, Class<T> clazz, String plural){
    try {
        ArrayList<T> al = new ArrayList<T>(o.size());
        al.addAll(o);
        JAXBContext jc = JAXBContext.newInstance(ArrayList.class);
        JAXBElement<ArrayList> amenity = new JAXBElement(new QName(plural), ArrayList.class, al);
        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        StringWriter writer = new StringWriter();
        marshaller.marshal(amenity, writer);
        return writer.toString();
    } catch (JAXBException e) {
        throw new RuntimeException(e);
    }
}

但结果仍然是一个空列表

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<pluralName/>

有没有一种方法，而不仅仅是手动将xml字符串粘贴在一起？

更新资料

从迈克尔Glavassevich [我已一些帮助能有一点需要注意做到这一点，各个元素是<Item>小号

//http://blog.bdoughan.com/2012/07/jaxb-no-annotations-required.html
@SuppressWarnings({ "unchecked", "rawtypes" })
public <T> String jaxb(Collection<T> elements, Class<T> elementClass, String plural){
    try {
        T[] array = (T[]) Array.newInstance(elementClass, elements.size());
        elements.toArray(array);
        JAXBContext jc = JAXBContext.newInstance(array.getClass());
        JAXBElement<T[]> topElement = new JAXBElement(new QName(plural), array.getClass(), array);
        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        StringWriter writer = new StringWriter();
        marshaller.marshal(topElement, writer);
        return writer.toString();
    } catch (JAXBException e) {
        throw new RuntimeException(e);
    }
}

结果变成

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Basketballs>
    <item>basketball one</item>
    <item>basketball two</item>
</Basketballs>

Answer 1

如果您不想创建包装器类，可以将集合转换为数组，将该数组放入a中JAXBElement，然后将其封送。

例如：

public class JAXBArrayWriter {

    public static class Item {
        @XmlValue
        protected String value;

        public Item() {}

        public Item(String value) {
            this.value = value;
        }
    }

    public static void main (String [] args) throws Exception {
        List<Item> items = new ArrayList<Item>();
        items.add(new Item("one"));
        items.add(new Item("two"));
        JAXBContext jc = JAXBContext.newInstance(Item[].class);
        JAXBElement<Item[]> root = new JAXBElement<Item[]>(new QName("items"), 
                Item[].class, items.toArray(new Item[items.size()]));
        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        StringWriter writer = new StringWriter();
        marshaller.marshal(root, writer);
        System.out.println(writer.toString());
    }
}

产生以下文档：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<items>
    <item>one</item>
    <item>two</item>
</items>