java - 从输入流创建文件

Question

我正在尝试将客户端提供的文件复制到临时文件中。

这个给定的文件由我的 REST 服务检索到 InputStream 中。

这是我的代码:

@POST
@Path("fileupload")
@Consumes(MediaType.MULTIPART_FORM_DATA)
public Response uploadFile(
    @FormDataParam("uploadFormElement") InputStream uploadedInputStream,
    @FormDataParam("uploadFormElement") FormDataContentDisposition fileDetail)
    throws IOException {

Response.Status respStatus = Response.Status.OK;

if (fileDetail == null) {
    respStatus = Response.Status.INTERNAL_SERVER_ERROR;
} else {
    if (uploadedInputStream != null) {
    try {
        initPath();
        int size = 0;
        int bytesRead;
        boolean isStreamSizeCorrect = true;
        byte[] buffer = new byte[1024];
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        while ((bytesRead = uploadedInputStream.read(buffer)) != -1) {
        if (size > OntoWebStudioUtil.getUploadFileLimit()) {
            isStreamSizeCorrect = false;
            baos.close();
            while ((bytesRead = uploadedInputStream.read(buffer)) != -1) {
            size++;
            }
            break;
        } else {
            baos.write(buffer, 0, bytesRead);
        }
        size++;
        }
        if (!isStreamSizeCorrect) {
        respStatus = Response.Status.NOT_ACCEPTABLE;
        return Response
            .status(respStatus)
            .entity("Size of uploaded file exceeds the limit"
                + OWSConstants.UPLOAD_RESPONSE_VALUE_SEPARATOR
                + size).build();
        }
        byte[] outBuf = baos.toByteArray();

        String newFilePath = "C:\\Docs\\my_pic.png";
        FileOutputStream fos = null;
        try {
        fos = new FileOutputStream(newFilePath);
        fos.write(outBuf);
        }
        catch (IOException e) {
            e.printStackTrace(System.err);
        }
         finally {
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
         }
    } catch (Exception e) {
        respStatus = Response.Status.INTERNAL_SERVER_ERROR;
        e.printStackTrace(System.out);
    }
    }
}
return Response
    .status(respStatus)
    .entity(tempFileName
        + OWSConstants.UPLOAD_RESPONSE_VALUE_SEPARATOR
        + currentFileName).build();
}
}

我遇到的问题是在我的临时目录中创建的文件是空的。 我必须在创建文件之前测试文件的大小。这就是我阅读 InputStream 的原因。所以我在阅读过程中试图复制一份它。但这不起作用。我能做什么？

谢谢

Answer 1

如果您使用的是 Java SE 7 或更高版本，则可以使用 Files.copy .