Question

我正在尝试创建第一个使用REST API的android应用程序。我的api是用Node.JS编写的，并且已经使用Postman进行了测试，但是，我无法将JSON数据发送到我的api。

    @Override
    protected String doInBackground(String... params) {

        String data = "";
        String urlName = params[0];

        HttpURLConnection httpURLConnection = null;
        try {

            httpURLConnection = (HttpURLConnection) new URL(urlName).openConnection();
            httpURLConnection.setRequestMethod("POST");

            httpURLConnection.setDoOutput(true);

            DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
            wr.writeBytes(params[1]);
            wr.flush();
            wr.close();

            InputStream in = httpURLConnection.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(in);

            int inputStreamData = inputStreamReader.read();
            while (inputStreamData != -1) {
                char current = (char) inputStreamData;
                inputStreamData = inputStreamReader.read();
                data += current;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (httpURLConnection != null) {
                httpURLConnection.disconnect();
            }
        }

        return data;
    }

我总是到达声明并初始化DataOutputSteam的行，并且不执行代码。我什至没有收到有关我的虚拟设备已经访问过我的服务器的日志。

我已经在清单XML中包含了这两个。

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />

Answer 1

根据您的日志，您遇到了NetworkOnMainThreadException，这阻止了网络请求的执行（取而代之的是进入您的catch块）。这表明您没有正确调用AsyncTask-确保您正在调用execute而不是doInBackground。另请参阅here，以获取有关此常规模式的更多信息。

Answer 2

尝试一下，这是用于POST方法的，它接受2个参数的电子邮件和密码。根据您的要求进行更改

URL url = new URL(Login_url);
            HttpURLConnection conn = (HttpURLConnection) new URL(urlName).openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Accept" , "application/json");
            conn.connect();

            Uri.Builder builder = new Uri.Builder()
                    .appendQueryParameter("email", "Your_Email")
                    .appendQueryParameter("password","Your_Password");
            String query = builder.build().getEncodedQuery();

            OutputStream os = conn.getOutputStream();
            BufferedWriter writer = new BufferedWriter(
                    new OutputStreamWriter(os, "UTF-8"));
            writer.write(query); 
            writer.flush();
            writer.close();
            os.close();
            code = conn.getResponseCode();

            Log.e("Result", code + "");

            InputStream input = conn.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(input));
            StringBuilder result = new StringBuilder();
            String line;

            while ((line = reader.readLine()) != null) {

                result.append(line);

            }

            Log.e("Result",result.toString());

发送POST请求到服务器

2 个答案: