java - example - Cómo transmitir un objeto JSON a una solicitud POST HttpURLConnection

peticion post java

Question

No puedo ver qué está mal con este código:

JSONObject msg; //passed in as a parameter to this method
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setDoOutput(true);
httpCon.setDoInput(true);
httpCon.setUseCaches(false);
httpCon.setRequestProperty( "Content-Type", "application/json" );
httpCon.setRequestProperty("Accept", "application/json");
httpCon.setRequestMethod("POST");
OutputStream os = httpCon.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");
msg.write(osw);
osw.flush();
osw.close();
os.close(); //probably overkill

En el servidor, no obtengo ningún contenido de publicación, una cadena de longitud cero.

Answer 1

Sigue este ejemplo:

public static PricesResponse getResponse(EventRequestRaw request) {
// String urlParameters = "param1=a&param2=b&param3=c";
String urlParameters = Piping.serialize(request);
HttpURLConnection conn = RestClient.getPOSTConnection(endPoint, urlParameters);
PricesResponse response = null;
try {
// POST
OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
writer.write(urlParameters);
writer.flush();
// RESPONSE
BufferedReader reader = new BufferedReader(new InputStreamReader((conn.getInputStream()), StandardCharsets.UTF_8));
String json = Buffering.getString(reader);
response = (PricesResponse) Piping.deserialize(json, PricesResponse.class);
writer.close();
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
conn.disconnect();
System.out.println("PricesClient: " + response.toString());
return response;
}
public static HttpURLConnection getPOSTConnection(String endPoint, String urlParameters) {
return RestClient.getConnection(endPoint, "POST", urlParameters);
}
public static HttpURLConnection getConnection(String endPoint, String method, String urlParameters) {
System.out.println("ENDPOINT " + endPoint + " METHOD " + method);
HttpURLConnection conn = null;
try {
URL url = new URL(endPoint);
conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod(method);
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "text/plain");
} catch (IOException e) {
e.printStackTrace();
}
return conn;
}

Answer 2

Tratar

...
httpCon.setRequestMethod("POST");
httpCon.connect(); // Note the connect() here
...
OutputStream os = httpCon.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");
...
osw.write(msg.toString());
osw.flush();
osw.close();

para enviar datos

para recuperar datos intente:

BufferedReader br = new BufferedReader(new InputStreamReader( httpCon.getInputStream(),"utf-8"));
String line = null;
while ((line = br.readLine()) != null) {
sb.append(line + "/n");
}
br.close();
System.out.println(""+sb.toString());

Answer 3

esto sin json Cadena de datos de la publicación al servidor

 class PostLogin extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
String response = null;
Uri.Builder builder= new Uri.Builder().appendQueryParameter("username","amit").appendQueryParameter("password", "amit");
String parm=builder.build().getEncodedQuery();
try
{
response = postData("your url here/",parm);
}catch (Exception e)
{
e.printStackTrace();
}
Log.d("test", "response string is:" + response);
return response;
}
}
private String postData(String path, String param)throws IOException {
StringBuffer response = null;
URL url = new URL(path);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
// connection.setRequestProperty("Content-Type", "application/json");
// connection.setRequestProperty("Accept", "application/json");
OutputStream out = connection.getOutputStream();
out.write(param.getBytes());
out.flush();
out.close();
int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line;
response = new StringBuffer();
while ((line = br.readLine()) != null) {
response.append(line);
}
br.close();
}
return response.toString();
}

Answer 4

HttpURLConnection es engorroso de usar. Con DavidWebb , una pequeña envoltura alrededor de HttpURLConnection, puedes escribirlo así:

JSONObject msg; //passed in as a parameter to this method
Webb webb = Webb.create();
JSONObject result = webb.post("http://my-url/path/to/res")
.useCaches(false)
.body(msg)
.ensureSuccess()
.asJsonObject()
.getBody();

Si no te gusta, hay una lista de bibliotecas alternativas en el enlace proporcionado.

¿Por qué todos deberíamos escribir el mismo código repetitivo todos los días? Por cierto, el código anterior es más legible y menos propenso a errores. HttpURLConnection tiene una interfaz horrible. Esto tiene que ser envuelto!

Answer 5

 public String sendHTTPData(String urlpath, JSONObject json) {
HttpURLConnection connection = null;
try {
URL url=new URL(urlpath);
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("Accept", "application/json");
OutputStreamWriter streamWriter = new OutputStreamWriter(connection.getOutputStream());
streamWriter.write(json.toString());
streamWriter.flush();
StringBuilder stringBuilder = new StringBuilder();
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK){
InputStreamReader streamReader = new InputStreamReader(connection.getInputStream());
BufferedReader bufferedReader = new BufferedReader(streamReader);
String response = null;
while ((response = bufferedReader.readLine()) != null) {
stringBuilder.append(response + "/n");
}
bufferedReader.close();
Log.d("test", stringBuilder.toString());
return stringBuilder.toString();
} else {
Log.e("test", connection.getResponseMessage());
return null;
}
} catch (Exception exception){
Log.e("test", exception.toString());
return null;
} finally {
if (connection != null){
connection.disconnect();
}
}
}`

llama a este methopd en doitbackground en asynctask