JAXB编组XMPP节 [英] JAXB marshalling XMPP stanzas

问题描述

我正在尝试使用以下代码段对邮件进行编组：

I am trying to marshall a message using the following snippet:

        JAXBContext jContext = JAXBContext.newInstance(Iq.class);
        Marshaller m = newJAXBContext.createMarshaller();
        m.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
        m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

        Bind bind = new Bind();
        bind.setResource("resource");
        Iq iq = new Iq();
        iq.setId(iqId);
        iq.setType("set");
        iq.getAnies().add(bind);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        m.marshal(iq, baos);

这里，Iq和Bind是由相关xmpp模式组成的对象。我的问题是，使用jaxb 2.0及更高版本，所有命名空间都在根元素中声明：

Here, Iq and Bind are the objects formed from the relevant xmpp schemas. My problem is, with jaxb 2.0 and later versions, all the namespaces are declared in the root element:

<iq from='[e-mail]/balcony'
     id='rg1'
     type='get'  xmlns='jabber:client'  xmlns:ns1='urn:ietf:params:xml:ns:xmpp-bind'> 
    <ns1:bind>
        <ns1:resource>resource</ns1:resource>
    </ns1:bind>
</iq>

但是，这里需要的是命名空间应占据适当的位置：

But, what is needed here is that the namespaces should occupy the appropriate places:

<iq from='[e-mail]/balcony'
     id="rg1"
     type="get" xmlns="jabber:client">
       <bind xmlns="urn:ietf:params:xml:ns:xmpp-bind">
             <resource>resource</resource>
       </bind>
</iq>

有没有办法编组xmpp节，就像你在第二个xml节中通过JAXB 2.0看到它们一样或更高版本？

Is there a way to marshall the xmpp stanzas as you see them in the 2nd xml stanza through JAXB 2.0 or later versions?

长话短说，我在这里有2个问题：
1.在适当的位置声明命名空间。
2.删除我理解的命名空间前缀可以使用NamespacePrefixMapper删除吗？但不确定，一个例子会很棒。

Long story short, I have 2 problems here: 1. Declaring the namespaces at appropriate locations. 2. removing the namespace prefix which I understand can be removed using the NamespacePrefixMapper? Not sure though, an example would be great.

推荐答案

以下情况如何？：

创建一个自定义XMLStreamWriter，它将所有命名空间声明视为默认命名空间，然后编组为：

Create a custom XMLStreamWriter that will treat all namespace declarations as default namespaces, and then marshal to that:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
XMLOutputFactory xof = XMLOutputFactory.newFactory();
XMLStreamWriter xsw = xof.createXMLStreamWriter(System.out);
xsw = new MyXMLStreamWriter(xsw);
m.marshal(iq, xsw);
xsw.close();

MyXMLStreamWriter

import java.util.Iterator;

import javax.xml.namespace.NamespaceContext;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

public class MyXMLStreamWriter implements XMLStreamWriter {

    private XMLStreamWriter xsw;
    private MyNamespaceContext nc = new MyNamespaceContext();

    public MyXMLStreamWriter(XMLStreamWriter xsw) throws Exception {
        this.xsw = xsw;
        xsw.setNamespaceContext(nc);
    }

    public void close() throws XMLStreamException {
        xsw.close();
    }

    public void flush() throws XMLStreamException {
        xsw.flush();
    }

    public NamespaceContext getNamespaceContext() {
        return xsw.getNamespaceContext();
    }

    public String getPrefix(String arg0) throws XMLStreamException {
        return xsw.getPrefix(arg0);
    }

    public Object getProperty(String arg0) throws IllegalArgumentException {
        return xsw.getProperty(arg0);
    }

    public void setDefaultNamespace(String arg0) throws XMLStreamException {
        xsw.setDefaultNamespace(arg0);
    }

    public void setNamespaceContext(NamespaceContext arg0) throws XMLStreamException {
    }

    public void setPrefix(String arg0, String arg1) throws XMLStreamException {
        xsw.setPrefix(arg0, arg1);
    }

    public void writeAttribute(String arg0, String arg1) throws XMLStreamException {
        xsw.writeAttribute(arg0, arg1);
    }

    public void writeAttribute(String arg0, String arg1, String arg2) throws XMLStreamException {
        xsw.writeAttribute(arg0, arg1, arg2);
    }

    public void writeAttribute(String arg0, String arg1, String arg2, String arg3) throws XMLStreamException {
        xsw.writeAttribute(arg0, arg1, arg2, arg3);
    }

    public void writeCData(String arg0) throws XMLStreamException {
        xsw.writeCData(arg0);
    }

    public void writeCharacters(String arg0) throws XMLStreamException {
        xsw.writeCharacters(arg0);
    }

    public void writeCharacters(char[] arg0, int arg1, int arg2) throws XMLStreamException {
        xsw.writeCharacters(arg0, arg1, arg2);
    }

    public void writeComment(String arg0) throws XMLStreamException {
        xsw.writeComment(arg0);
    }

    public void writeDTD(String arg0) throws XMLStreamException {
        xsw.writeDTD(arg0);
    }

    public void writeDefaultNamespace(String arg0) throws XMLStreamException {
        xsw.writeDefaultNamespace(arg0);
    }

    public void writeEmptyElement(String arg0) throws XMLStreamException {
        xsw.writeEmptyElement(arg0);
    }

    public void writeEmptyElement(String arg0, String arg1) throws XMLStreamException {
        xsw.writeEmptyElement(arg0, arg1);
    }

    public void writeEmptyElement(String arg0, String arg1, String arg2) throws XMLStreamException {
        xsw.writeEmptyElement(arg0, arg1, arg2);
    }

    public void writeEndDocument() throws XMLStreamException {
        xsw.writeEndDocument();
    }

    public void writeEndElement() throws XMLStreamException {
        xsw.writeEndElement();
    }

    public void writeEntityRef(String arg0) throws XMLStreamException {
        xsw.writeEntityRef(arg0);
    }

    public void writeNamespace(String arg0, String arg1) throws XMLStreamException {
    }

    public void writeProcessingInstruction(String arg0) throws XMLStreamException {
        xsw.writeProcessingInstruction(arg0);
    }

    public void writeProcessingInstruction(String arg0, String arg1) throws XMLStreamException {
        xsw.writeProcessingInstruction(arg0, arg1);
    }

    public void writeStartDocument() throws XMLStreamException {
        xsw.writeStartDocument();
    }

    public void writeStartDocument(String arg0) throws XMLStreamException {
        xsw.writeStartDocument(arg0);
    }

    public void writeStartDocument(String arg0, String arg1) throws XMLStreamException {
        xsw.writeStartDocument(arg0, arg1);
    }

    public void writeStartElement(String arg0) throws XMLStreamException {
        xsw.writeStartElement(arg0);
    }

    public void writeStartElement(String arg0, String arg1) throws XMLStreamException {
        xsw.writeStartElement(arg0, arg1);
    }

    public void writeStartElement(String arg0, String arg1, String arg2) throws XMLStreamException {
        xsw.writeStartElement("", arg1, arg2);
        if(null != arg2 || arg2.length() > 0) {
            String currentDefaultNS = nc.getNamespaceURI("");
            if(!arg2.equals(currentDefaultNS)) {
                writeDefaultNamespace(arg2);
                nc.setDefaultNS(arg2);
            }
        }
     }

    private static class MyNamespaceContext implements NamespaceContext {

        private String defaultNS = "";

        public void setDefaultNS(String ns) {
            defaultNS = ns;
        }

        public String getNamespaceURI(String arg0) {
            if("".equals(arg0)) {
                return defaultNS;
            }
            return null;
        }

        public String getPrefix(String arg0) {
            return "";
        }

        public Iterator getPrefixes(String arg0) {
            return null;
        }

    }
}

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