在Jersey中使用XML文件进行POST时出现SAXParseException

我在休息应用程序中使用JAXB。我想通过Web表单发送一个XML文件。然后Java类将解封 InputStream .

private void unmarshal(Class<T> docClass, InputStream inputStream)
    throws JAXBException {
    String packageName = docClass.getPackage().getName();
    JAXBContext context = JAXBContext.newInstance(packageName);
    Unmarshaller unmarshaller = context.createUnmarshaller();
    Object marshaledObject = unmarshaller.unmarshal(inputStream);
}

触发 unmarshal 方法有 form 看起来是这样的:

<form action="#" method="POST">
    <label for="id">File</label>
    <input name="file" type="file" />
    <input type="submit" value="Submit" />
</form>

我得到以下ParserException:

javax.xml.bind.UnmarshalException - with linked exception: [org.xml.sax.SAXParseException: Content is not allowed in prolog.] .

这个问题得到了一般性的回答。 here ,但我确信我的文件没有损坏。当我从同一个文件中调用Java类的代码时,不会抛出异常。

// causes no exception
File file = new File("MyFile.xml");
FileInputStream fis = new FileInputStream(file);
ImportFactory importFactory = ImportFactory.getInstance();
importFactory.setMyFile(fis);

// but when i pass the file with a web form
@POST
@Produces(MediaType.TEXT_HTML)
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response create(@FormParam("file") InputStream filestream) {
    Response response;

    // is a BufferedInputStream, btw    
    LOG.debug("file is type: " + filestream.getClass().getName());

    try { 
        ImportFactory importFactory = ImportFactory.getInstance();
        importFactory.setMyFile(filestream);

        Viewable viewable = new Viewable("/sucess", null);
        ResponseBuilder responseBuilder = Response.ok(viewable);
        response = responseBuilder.build();

    } catch (Exception e) {
        LOG.error(e.getMessage(), e);
        ErrorBean errorBean = new ErrorBean(e);
        Viewable viewable = new Viewable("/error", errorBean);
        ResponseBuilder responseBuilder = Response.ok(viewable);
        response = responseBuilder.build();
    }
    return response;
}