HTTP POST using JSON in Java

Question

I would like to make a simple HTTP POST using JSON in Java.

Let\'s say the URL is www.site.com

and it takes in the value {\"name\":\"mynam

Answer 1

@momo's answer for Apache HttpClient, version 4.3.1 or later. I'm using JSON-Java to build my JSON object:

JSONObject json = new JSONObject();
json.put("someKey", "someValue");    

CloseableHttpClient httpClient = HttpClientBuilder.create().build();

try {
    HttpPost request = new HttpPost("http://yoururl");
    StringEntity params = new StringEntity(json.toString());
    request.addHeader("content-type", "application/json");
    request.setEntity(params);
    httpClient.execute(request);
// handle response here...
} catch (Exception ex) {
    // handle exception here
} finally {
    httpClient.close();
}

Answer 2

For Java 11 you can use new HTTP client:

 HttpClient client = HttpClient.newHttpClient();
    HttpRequest request = HttpRequest.newBuilder()
        .uri(URI.create("http://localhost/api"))
        .header("Content-Type", "application/json")
        .POST(ofInputStream(() -> getClass().getResourceAsStream(
            "/some-data.json")))
        .build();

    client.sendAsync(request, BodyHandlers.ofString())
        .thenApply(HttpResponse::body)
        .thenAccept(System.out::println)
        .join();

You can use publisher from InputStream, String, File. Converting JSON to the String or IS you can with Jackson.

Answer 3

Here is what you need to do:

1. Get the Apache HttpClient, this would enable you to make the required request
2. Create an HttpPost request with it and add the header application/x-www-form-urlencoded
3. Create a StringEntity that you will pass JSON to it
4. Execute the call

The code roughly looks like (you will still need to debug it and make it work):

// @Deprecated HttpClient httpClient = new DefaultHttpClient();
HttpClient httpClient = HttpClientBuilder.create().build();
try {
    HttpPost request = new HttpPost("http://yoururl");
    StringEntity params = new StringEntity("details={\"name\":\"xyz\",\"age\":\"20\"} ");
    request.addHeader("content-type", "application/x-www-form-urlencoded");
    request.setEntity(params);
    HttpResponse response = httpClient.execute(request);
} catch (Exception ex) {
} finally {
    // @Deprecated httpClient.getConnectionManager().shutdown(); 
}

Answer 4

I recomend http-request built on apache http api.

HttpRequest<String> httpRequest = HttpRequestBuilder.createPost(yourUri, String.class)
    .responseDeserializer(ResponseDeserializer.ignorableDeserializer()).build();

public void send(){
   ResponseHandler<String> responseHandler = httpRequest.execute("details", yourJsonData);

   int statusCode = responseHandler.getStatusCode();
   String responseContent = responseHandler.orElse(null); // returns Content from response. If content isn't present returns null. 
}

If you want send JSON as request body you can:

  ResponseHandler<String> responseHandler = httpRequest.executeWithBody(yourJsonData);

I higly recomend read documentation before use.

Answer 5

protected void sendJson(final String play, final String prop) {
     Thread t = new Thread() {
     public void run() {
        Looper.prepare(); //For Preparing Message Pool for the childThread
        HttpClient client = new DefaultHttpClient();
        HttpConnectionParams.setConnectionTimeout(client.getParams(), 1000); //Timeout Limit
        HttpResponse response;
        JSONObject json = new JSONObject();

            try {
                HttpPost post = new HttpPost("http://192.168.0.44:80");
                json.put("play", play);
                json.put("Properties", prop);
                StringEntity se = new StringEntity(json.toString());
                se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
                post.setEntity(se);
                response = client.execute(post);

                /*Checking response */
                if (response != null) {
                    InputStream in = response.getEntity().getContent(); //Get the data in the entity
                }

            } catch (Exception e) {
                e.printStackTrace();
                showMessage("Error", "Cannot Estabilish Connection");
            }

            Looper.loop(); //Loop in the message queue
        }
    };
    t.start();
}