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Calling Post request without body in java

I have a post API which doesn't accept any input. I have to get output from API. But it is giving compilation error.
HttpURLConnection connection = null;
String targetUrl="https://idcs-oda-9417f93560b94eb8a2e2a4c9aac9a3ff-t0.data.digitalassistant.oci.oc-test.com/api/v1/bots/"+BotID+"/dynamicEntities/"+dynamicEntityId+"/pushRequests
URL url = new URL(targetUrl);
connection=(HttpURLConnection) url.openConnection();
connection.setUseCaches (false);
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
connection.setRequestProperty("Authorization", "Basic aWRjcy1vZGEtOTQxN2Y5MzU2MGI5NGViOGEyZTJhNGM5YWFjOWEzZmYtdDBfQVBQSUQ6MjQ0YWU4ZTItNmY3MS00YWYyLWI1Y2MtOTExMDg5MGQxNDU2");
connection.setRequestProperty("Accept", "application/json");
OutputStream os = connection.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");
**osw.write();** //this line is expecting input in parameter
osw.flush();
osw.close();
os.close();
connection.connect();
If I dont pass any value in osw.write() it gives compilation error. How can I resolve the same.

Look at the following method for the post call. You will need to add the outputstream to the osw.write() as it expects a parameter.
private static void sendPOST() throws IOException {
URL obj = new URL(POST_URL);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", USER_AGENT);
// For POST only - START
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
os.write(POST_PARAMS.getBytes());
os.flush();
os.close();
// For POST only - END
int responseCode = con.getResponseCode();
System.out.println("POST Response Code :: " + responseCode);
if (responseCode == HttpURLConnection.HTTP_OK) { //success
BufferedReader in = new BufferedReader(new InputStreamReader(
con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
// print result
System.out.println(response.toString());
}
else {
System.out.println("POST request not worked");
}
}
For more details on the above code look here.

Sending special characters using HttpURLConnection in Java

I have a web service and I want to invoke that with "application/x-www-form-urlencoded" content type. The request sometimes contains special characters such as + * - and .... The problem is that destination web service doesn't receive the request perfectly. It receives something like this: "////////////////w==" almost all characters are turned to / . What is the problem?
Here is my code:
URL url = new URL("a-web-service-url");
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setDoInput(true);
httpURLConnection.setDoOutput(true);
httpURLConnection.setUseCaches(false);
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(httpURLConnection.getOutputStream(), "UTF-8");
outputStreamWriter.write("test=/-+*=!##$%^&*()_");
outputStreamWriter.flush();
InputStream inputStream = httpURLConnection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder;
String line;
for (stringBuilder = new StringBuilder(); (line = bufferedReader.readLine()) != null; stringBuilder = stringBuilder.append(line)) {
;
}
bufferedReader.close();
httpURLConnection.disconnect();
String response = stringBuilder.toString().trim();
The web service receives:
test=////////////////w==

Use URLEncoder to encode the string before sending.
URLEncoder.encode(message, "UTF-8" );
In this case it will be
outputStreamWriter.write(URLEncoder.encode("test=/-+*=!##$%^&*()_", "UTF-8" ));

Error with cURL and java String variable

I'm trying to use glot.io api to compile java code with curl.
I read a text file :
BufferedReader bufferedReader = new BufferedReader(new FileReader("input.txt"));
StringBuffer stringBuffer = new StringBuffer();
String line = bufferedReader.readLine();
while(line != null){
stringBuffer.append(line);
line = bufferedReader.readLine();
}
If I use no quotation marks, I have no problem when I request the url
URL obj = new URL(url);
HttpURLConnection conn = (HttpURLConnection) obj.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty ("Authorization", "Token myToken");
conn.setRequestProperty("Content-Type", "application/json");
String data = "{\"files\": [{\"name\": \"main.java\", \"content\": \"" + stringBuffer.toString() + "\"}]}";
OutputStreamWriter out = new OutputStreamWriter(conn.getOutputStream());
out.write(data);
out.close();
BufferedReader bf = new BufferedReader(new InputStreamReader(conn.getInputStream()));
System.out.println(bf.readLine());
But when I use String in my code, the web page return 400 error.
Can you help me ?

Send JSON data through POST in Java

I have this code to send JSON data (passed as a string) to the server (This code works when English characters are to be sent as values in dataJSON as far as I tested):
private static String sendPost(String url, String dataJSON) throws Exception {
System.out.println("Data to send: " + dataJSON);
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
String type = "application/json;charset=utf-8";
// add reuqest header
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", "Mozilla/5.0");
con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
con.setRequestProperty("Content-Length", String.valueOf(dataJSON.getBytes("UTF-8").length));
con.setRequestProperty("Content-Type", type);
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeUTF(dataJSON);
wr.flush();
wr.close();
int responseCode = con.getResponseCode();
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Response Code : " + responseCode);
BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
System.out.print("Response string from POST: " + response.toString() + "\n");
return response.toString();
}
Problem is I don't get correct response, which I get for example using DHC Restlet Client.
The problem is I think the dataJSON must be encoded in UTF8. That's how the server expects it most likely.
But it seems I have some problem in code the way I try to convert it and send it.
Can someone help me send data in body as UTF8 string in above example?

I think I solved with this approach:
private static String sendPost2(String urlStr, String dataJSON) throws Exception {
URL url = new URL(urlStr);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");
OutputStream os = conn.getOutputStream();
os.write(dataJSON.getBytes("UTF-8"));
os.close();
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
String result = new BufferedReader(new InputStreamReader(in)) .lines().collect(Collectors.joining("\n"));
in.close();
conn.disconnect();
return result;
}
Please suggest alternative if you see problem with it.

Http get response utf-8

I have following code. When i get the response, it's characters are faulty. i want to get the response with "UTF-8". How and where can i write that in my code below?
Thanks
URL httpPost = new URL(url);
HttpsURLConnection connection = (HttpsURLConnection) httpPost.openConnection();
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setDoInput(true);
connection.getOutputStream().write(params.getBytes(Charset.forName("UTF-8")));
connection.getOutputStream().flush();
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream(),"UTF-8"));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
try {
String responseFromServer = response.toString();
dealsResponse = Utils.mapper.readValue(responseFromServer, GetDealsResponse.class);
} finally {
in.close();
}

connection.setRequestProperty("Accept-Charset", "UTF-8");