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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.

Get the Response from POST request

I would like to obtain the response from a HttpsURLConnection POST request.
If I try to do the request with PostMan, I have one message as response (es: 1520). I have to save this code, but I find the method for read just the getResponseCode() (200) or getResponseMessage() ("OK"). I should use another libraries? Because in the HttpsUrlConnection method I don't find anything useful (https://docs.oracle.com/javase/7/docs/api/java/net/HttpURLConnection.html)
My code is:
HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
con.setSSLSocketFactory(sslContext.getSocketFactory());
con.setDoOutput(true);
con.setUseCaches(false);
con.setRequestMethod("POST");
con.setRequestProperty("Connection", "keep-alive");
con.setRequestProperty("Content-Type", w_AECONTYP);
con.setRequestProperty("Accept-Charset", w_AEACCCHA);
con.setRequestProperty("Accept-Encoding", w_AEACCENC);
StringBuilder postFile = new StringBuilder();
byte[] postFileBytes =w_FileToSend.getBytes("UTF-8");
con.setDoOutput(true);
try {
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.write(postFileBytes);
wr.flush();
wr.close();
} catch (Exception e) {
System.out.println("Connection Failed");
e.printStackTrace();
}
int responseCode = con.getResponseCode();
// get 200 code "OK"
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
But when arrived at the WHILE loop, it doesn't enter in the cycle.
How I can do this?
The file is in JSON format, but that isn't the problem.
I need to save that 915 code!!

You could use HttpResponse and HttpPost for getting a response from server (as well as the Response Code):
HttpResponse httpResponse = httpClient.execute(new HttpPost(URL));
InputStream inputStream = httpResponse.getEntity().getContent();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder = new StringBuilder();
String bufferedStrChunk = null;
while((bufferedStrChunk = bufferedReader.readLine()) != null){
stringBuilder.append(bufferedStrChunk);
}
// now response is in the stringBuilder.toString()
I hope this will help you.

In HttpURLConnection Why don't JSONObject as Params work but String as Params are working

I am using HttpUrlConnection to post some data to my server here is the function:
private String register(String myurl) throws IOException {
String resp = null;
try {
JSONObject parameters = new JSONObject();
// parameters.put("jsonArray", ((makeJSON())));
parameters.put("key", "key");//getencryptkey());
URL url = new URL(myurl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
// conn.setReadTimeout(10000 /* milliseconds *///);
// conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestProperty("Content-Type", "application/json");
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");
OutputStream out = new BufferedOutputStream(conn.getOutputStream());
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
writer.write(parameters.toString());
writer.close();
out.close();
int responseCode = conn.getResponseCode();
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Response Code : " + responseCode);
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
System.out.println("strngbuffr" + response.toString());
resp = response.toString();
} catch (Exception exception) {
System.out.println("Exception: " + exception);
}
System.out.println("rsp"+ resp.toString());
return resp.toString();
}
I get the response code as 200, which means connection is okay however I get empty variables on PHP side, what can be wrong here?
Earlier I was sending a JSON array too but just to test functonality I commented that out now I am only sending one variable key as "key"
Its amazing to see, this sample code works - sans the JSON array and the key value pairs:
private String sendPost(String url) throws Exception {
String USER_AGENT = "Mozilla/5.0";
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
//add reuqest header
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", USER_AGENT);
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
String urlParameters ="sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
int responseCode = con.getResponseCode();
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Post parameters : " + urlParameters);
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();
//print result
System.out.println("rvsp"+response.toString());
return response.toString();
}
So it boils down to replacing this:
JSONObject parameters = new JSONObject();
parameters.put("jsonArray", new JSONArray(Arrays.asList(makeJSON())));
parameters.put("key", getencryptkey());
by this:
String urlParameters ="jArr="+makeJSON()+"Key="+getencryptkey();
and I am still curious.

I reckon the problem here is not at the Java side, If the parameters is of fixed type like in json in your case, the JSON Object as POST params method will work if collected this way on the php side:
<?php
$json = file_get_contents('php://input');
$obj = json_decode($json);
print_r($obj);
print_r("this is a test response");
?>

The problem here was not with the Java side, it was with the php side, the JSON Object as POST params method will work if collected this way on the php side:
<?php
$json = file_get_contents('php://input');
$obj = json_decode($json);
print_r($obj);
print_r("this is a test");
?>

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");

return StringBuffer array

I'm using StringBuffer to send and receive variables from a web service.
My code is:
// Create connection
url = new URL(urlSCS + "/login");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Length",
"" + Integer.toString(urlParameters.getBytes().length));
connection.setRequestProperty("Content-Language", "pl-PL");
connection.setUseCaches(false);
connection.setDoInput(true);
connection.setDoOutput(true);
// Send request
DataOutputStream wr = new DataOutputStream(
connection.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
// Get Response
InputStream is = connection.getInputStream();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
String line;
StringBuffer response = new StringBuffer();
while ((line = rd.readLine()) != null) {
response.append(line);
response.append('\r');
}
rd.close();
How can I change this code to be able to receive Array instead of String?
The request which I get from the web service is like this: {"var", "var"}.

This might help
http://www.coderanch.com/t/393008/java/java/explode-Java
Remember to cut the response from {} using response.substring()!
look at:
String partsColl = "A,B,C";
String[] partsCollArr;
String delimiter = ",";
partsCollArr = partsColl.split(delimiter);
you will have your responses in "" so substring them then.
Good luck!