HttpURLConnection发送中文乱码问题解决

/**
     * 发送http POST请求
     *
     * @param
     * @return 远程响应结果
     */
    public static String sendPost(String u, String json) throws Exception {
        StringBuffer sbf = new StringBuffer();
        try {
            URL url = new URL(u);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");
            connection.setUseCaches(false);
            connection.setInstanceFollowRedirects(true);
            connection.addRequestProperty("Content-Type", "application/json");
            connection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
            connection.connect();
            DataOutputStream out = new DataOutputStream(connection.getOutputStream());
            if (!"".equals(json)) {
                //out.writeBytes(json);
                out.write(json.getBytes());
            }
            out.flush();
            out.close();

            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String lines;
            while ((lines = reader.readLine()) != null) {
                lines = new String(lines.getBytes(), "utf-8");
                sbf.append(lines);
            }
            System.out.println(sbf);
            reader.close();
            // 断开连接
            connection.disconnect();
        } catch (IOException e) {
            e.printStackTrace();
            throw e;
        }
        return sbf.toString();
    }

public final void writeBytes(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
out.write((byte)s.charAt(i));
}
incCount(len);
}