java - 使用 JAXB 解码 XOP

Question

我的数据源已从 Base64 嵌入图像数据切换到 XOP 图像数据。我正在使用 Java/JAXB 来解码数据，但找不到任何描述其完成方式的良好来源。所有引用文献似乎都描述了使用 SOAP 消息执行此操作，这似乎为您解决了一些繁重的工作。

在我的例子中，数据实际上是作为字符串传入的，需要将其解码到 JAXB 创建的对象中。由于新消息以

开头

Mime-Version: 1.0
Content-Type: multipart/related; start-info="text/xml"; type="application/xop+xml"; 
    start="<-963165769043289641.1400077877224@xxxxxyyyyyy.ca>"; 
    boundary="----=_Part_0_-338193320.1400077877317"

显然，它不会将数据解码为 XML，因为它看起来不像 XML(序言之前不允许有数据)。

这可以用 JAXB 来完成吗？从模式创建对象似乎工作正常，并且创建了看起来像正确的对象(它创建了一个 Include 元素)。我尝试过手动创建 AttachmentUnmarshaller 但没有帮助...传入的数据仍然无法识别为 XML。我觉得我错过了一个基本步骤，但找不到任何好的引用资料或示例。

任何帮助将不胜感激。

Answer 1

下面是一种可能有帮助的方法。

消息

以下是您将要处理的大致内容:

 MIME-Version: 1.0
 Content-Type: Multipart/Related;boundary=MIME_boundary;
 ...
 --MIME_boundary
 Content-Type: application/xop+xml; 
 ...

 <soap:Envelope ...
  <soap:Body>...
    <foo>
      <photo xmlmime:contentType='image/png'>
        <xop:Include xmlns:xop='http://www.w3.org/2004/08/xop/include' 
           href='cid:http://example.org/me.jpeg'/></m:photo>
 ...

 --MIME_boundary
 Content-Type: image/png
 Content-Transfer-Encoding: binary
 Content-ID: <http://example.org/me.png>

 // binary octets for png

演示代码

演示

下面的代码假设您已处理消息以执行以下操作:

1. 提取 XML 片段
2. 提取附件并能够在 cid 上键入它们。

import java.io.File;
import javax.xml.bind.*;

public class Demo {

    private static String base64 = "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";

    public static void main(String[] args) throws Exception {
        // Create the JAXBContext & Unmarshaller
        JAXBContext jc = JAXBContext.newInstance(Foo.class);
        Unmarshaller unmarshaller = jc.createUnmarshaller();

        // Create a custom AttachementUnmarshaller.  Populate the Map
        // AttachmentUnmarshaller with the attachments keyed on the cid.
        MyAttachmentUnmarshaller attachmentUnmarshaller = new MyAttachmentUnmarshaller();
        attachmentUnmarshaller.getAttachments().put("cid:http://example.org/me.jpeg", DatatypeConverter.parseBase64Binary(base64));

        // Set the AttachmentUnmarshaller on the Unmarshaller
        unmarshaller.setAttachmentUnmarshaller(attachmentUnmarshaller);

        // Unmarshal the XML piece
        File xml = new File("src/forum24407360/input.xml");
        Foo foo = (Foo) unmarshaller.unmarshal(xml);
    }

}

MyAttachmentUnmarshaller

下面是 AttachmentUnmarshaller 的样子。 cid 中传入一个 AttachmentUnmarshaller，负责返回相应的二进制数据。在 JAX-WS 环境中，这是自动为您处理的，但没有什么可以阻止您手动执行此操作。您可以在这里找到有关它的更多信息:What's the most standard Java way to store raw binary data along with XML? .

import java.io.*;
import java.util.*;
import javax.activation.*;
import javax.xml.bind.attachment.AttachmentUnmarshaller;

public class MyAttachmentUnmarshaller extends AttachmentUnmarshaller {

    private Map<String, byte[]> attachments = new HashMap<String, byte[]>();

    public Map<String, byte[]> getAttachments() {
        return attachments;
    }

    @Override
    public DataHandler getAttachmentAsDataHandler(String cid) {
        byte[] bytes = attachments.get(cid);
        return new DataHandler(new ByteArrayDataSource(bytes));
    }

    @Override
    public byte[] getAttachmentAsByteArray(String cid) {
        return attachments.get(cid);
    }

    @Override
    public boolean isXOPPackage() {
        return true;
    }

    private static class ByteArrayDataSource implements DataSource {

        private byte[] bytes;

        public ByteArrayDataSource(byte[] bytes) {
            this.bytes = bytes;
        }

        public String getContentType() {
            return  "application/octet-stream";
        }

        public InputStream getInputStream() throws IOException {
            return new ByteArrayInputStream(bytes);
        }

        public String getName() {
            return null;
        }

        public OutputStream getOutputStream() throws IOException {
            return null;
        }

    }

}

XML 片段

<foo>
    <image>
        <xop:Include xmlns:xop="http://www.w3.org/2004/08/xop/include" href="cid:http://example.org/me.jpeg"/>
    </image>
</foo>