http post请求错误 fileNotfoundexception 404

<form action="/upload/" enctype="multipart/form-data" method="post">

            <input name="file" type="file">

            <input type="submit" value="Submit">

            <input type="text" name="username" value="[email protected]">

        </form>

/**

	 * @Description: TODO(带参，文件上传)

	 * @param actionUrl

	 * @param params

	 * @param files

	 * @return result

	 * @throws IOException

	 */

	public static String post(String actionUrl, Map<String, String> params,

			Map<String, File> files) throws IOException {



		String BOUNDARY = java.util.UUID.randomUUID().toString();

		String PREFIX = "--", LINEND = "\r\n";

		String MULTIPART_FROM_DATA = "multipart/form-data";

		String CHARSET = "UTF-8";



		URL uri = new URL(actionUrl);

		HttpURLConnection conn = (HttpURLConnection) uri.openConnection();



		conn.setReadTimeout(5 * 1000);

		conn.setDoInput(true);// 允许输入

		conn.setDoOutput(true);// 允许输出

		conn.setUseCaches(false);

		conn.setRequestMethod("POST"); // Post方式

		conn.setRequestProperty("connection", "keep-alive");

		conn.setRequestProperty("Charsert", "UTF-8");



		conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA

				+ ";boundary=" + BOUNDARY);



		// 首先组拼文本类型的参数

		StringBuilder sb = new StringBuilder();

		for (Map.Entry<String, String> entry : params.entrySet()) {

			sb.append(PREFIX);

			sb.append(BOUNDARY);

			sb.append(LINEND);

			sb.append("Content-Disposition: form-data; name=\""

					+ entry.getKey() + "\"" + LINEND);

			sb.append("Content-Type: text/plain; charset=" + CHARSET + LINEND);

			sb.append("Content-Transfer-Encoding: 8bit" + LINEND);

			sb.append(LINEND);

			sb.append(entry.getValue());

			sb.append(LINEND);

		}



		DataOutputStream outStream = new DataOutputStream(

				conn.getOutputStream());

		outStream.write(sb.toString().getBytes());

		// 发送文件数据

		if (files != null)

			for (Map.Entry<String, File> file : files.entrySet()) {

				StringBuilder sb1 = new StringBuilder();

				sb1.append(PREFIX);

				sb1.append(BOUNDARY);

				sb1.append(LINEND);

				sb1.append("Content-Disposition: form-data; name=\"file\"; filename=\""

						+ file.getKey() + "\"" + LINEND);

				sb1.append("Content-Type: application/octet-stream; charset="

						+ CHARSET + LINEND);

				sb1.append(LINEND);

				outStream.write(sb1.toString().getBytes());



				InputStream is = new FileInputStream(file.getValue());

				Log.i("文件大小", file.getValue().length() + "");

				byte[] buffer = new byte[1024];

				int len = 0;

				while ((len = is.read(buffer)) != -1) {

					outStream.write(buffer, 0, len);

				}



				is.close();

				outStream.write(LINEND.getBytes());

			}



		// 请求结束标志

		byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes();

		outStream.write(end_data);

		outStream.flush();

		// 得到响应码

		int res = conn.getResponseCode();

		Log.i("图片上传结果", res + "");

		InputStream in = conn.getInputStream();

		InputStreamReader isReader = new InputStreamReader(in);



		BufferedReader bufReader = new BufferedReader(isReader);



		String line = null;

		String data = "OK";

		while ((line = bufReader.readLine()) == null)

			data += line;



		if (res == 200) {

			int ch;

			StringBuilder sb2 = new StringBuilder();

			while ((ch = in.read()) != -1) {

				sb2.append((char) ch);

			}

		}

		outStream.close();

		conn.disconnect();

		return in.toString();

	}