http post 上传文件

[ymjavasoft]

			 List<String> list  = new ArrayList<String>();
			 list.add("d:\\test.doc");
			String BOUNDARY = "A300x"; // 定义数据分隔线
			URL urls = new URL(url);
			HttpURLConnection conn = (HttpURLConnection) urls.openConnection();
			 // 发送POST请求必须设置如下两行
			conn.setDoOutput(true);
			conn.setDoInput(true);
			conn.setUseCaches(false);
			conn.setRequestMethod("POST");
			conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
			OutputStream out = new DataOutputStream(conn.getOutputStream());
			byte[] end_data = ("\r\n--" + BOUNDARY + "--\r\n").getBytes();// 定义最后数据分隔线
			int leng = list.size();
			for(int i=0;i<leng;i++){
				String fname = list.get(i);
				File file = new File(fname);
				StringBuilder sb = new StringBuilder();
				sb.append("--");
				sb.append(BOUNDARY);
				sb.append("\r\n");
				sb.append("Content-Disposition:name=\"file\";filename=\""+ URLEncoder.encode(file.getName(), "UTF-8") +"\"\r\n");
				sb.append("Content-Type:application/octet-stream\r\n\r\n");
				sb.append("--"+BOUNDARY+"--");
				byte[] data = sb.toString().getBytes();
				out.write(data);
				DataInputStream in = new DataInputStream(new FileInputStream(file));
				int bytes = 0;
				byte[] bufferOut = new byte[1024];
				while ((bytes = in.read(bufferOut)) != -1) {
					out.write(bufferOut, 0, bytes);
				}
				
				out.write("\r\n".getBytes()); //多个文件时，二个文件之间加入这个
				System.out.println(sb.toString()); 
				in.close();
			 	}
			out.write(end_data);
			out.flush();
			out.close();
				// 定义BufferedReader输入流来读取URL的响应
			BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
			String line = null;
			while ((line = reader.readLine()) != null) {
				System.out.println(line);
			}

--------------------------------------------------
报错

{"error":
{"code":"request_body_invalid",
"message":"The provided request entity body has invalid value for the 'Content-Disposition' header.
Expected format is 'Content-Disposition: form-data;name="file";filename="[FileName]"'."
}
}
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官方API提供格式
POST https://apis.live.net/v5.0/me/skydrive/files?access_token=ACCESS_TOKEN

Content-Type: multipart/form-data; boundary=A300x

--A300x
Content-Disposition: form-data; name="file"; filename="HelloWorld.txt"
Content-Type: application/octet-stream

Hello, World!
--A300x--

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为什么报错啊，我是这样写的呢。求大神帮忙看看啊