在DataStore中将InputStream存储为GAE Blob

Question

我有一个模型实体Image 实体的字段类型为：Blob 要执行文件上传，请使用Apache Commons FileUpload Library 要获取我的文件，我使用以下代码：

    Image image = new Image();
    ServletFileUpload upload = new ServletFileUpload();
    try {
        FileItemIterator itr = upload.getItemIterator(req);
        while(itr.hasNext()){
            FileItemStream item = itr.next();

            if(!item.isFormField())
            {
                image.setImageType(item.getContentType());
                InputStream stream = item.openStream();
                image.setImageData(???); //How to Set Blob Data from Input Stream
            }
        }
    } catch (FileUploadException e) {
        resp.sendError(500);
    }

感谢。

Answer 1

使用Apache Commons FileUpload附带的Streams.copy(input, output, doClose)实用程序方法将InputStream复制到字节数组中并从中创建Blob：

InputStream stream = ...
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
Streams.copy(stream, bytes, true /* close stream after copy */);
Blob blob = new Blob(bytes.toByteArray());
image.setImageData(blob);