/**
	 * 
	 * 
	 * 
	 * @param actionUrl
	 *            请求上传的服务器地址
	 * @param params
	 *            普通表单字段的name与value
	 * @param files
	 *            文件字段文件名与文件
	 * @return
	 * 
	 * @throws IOException
	 */

	private 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); // 缓存的最长时间
		conn.setDoInput(true);// 允许输入
		conn.setDoOutput(true);// 允许输出
		conn.setUseCaches(false); // 不允许使用缓存
		conn.setRequestMethod("POST");
		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());
				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();
		StringBuilder sb2 = new StringBuilder();
		if (res == 200) {
			InputStream in = conn.getInputStream();
			int ch;
			while ((ch = in.read()) != -1) {
				sb2.append((char) ch);
			}
		}
		outStream.close();
		conn.disconnect();
		return sb2.toString();
	}