Code snippet - Java Unirest library

Unirest

HTTP requests made easy - http://unirest.io/java.html

Sample code 1:

Unirest.post("http://httpbin.org/post")
  .queryString("name", "Marco")
  .field("last", "Polo")
  .asJson()

Sample code 2:

HttpResponse<JsonNode> jsonResponse = Unirest.post("http://httpbin.org/post")
  .header("accept", "application/json")
  .queryString("apiKey", "123")
  .field("parameter", "value")
  .field("foo", "bar")
  .asJson();

Add this to the pom.xml:

<dependency>
    <groupId>com.mashape.unirest</groupId>
    <artifactId>unirest-java</artifactId>
    <version>1.4.5</version>
</dependency>

This code checks a reCaptcha response.

        try {
            HttpResponse<JsonNode> jsonResponse = Unirest.post("https://www.google.com/recaptcha/api/siteverify")
                    .field("secret", secret)
                    .field("response", response)
                    .asJson();
            return jsonResponse.getBody().getObject().getBoolean("success");
        } catch (UnirestException | JSONException e) {
            LOGGER.error("Unirest http call failed", e);
            return false;
        }

http://httpbin.org/ helps with testing request/responses.

Async requests:

Future<HttpResponse<JsonNode>> future = Unirest.post("http://httpbin.org/post")
  .header("accept", "application/json")
  .field("param1", "value1")
  .field("param2", "value2")
  .asJsonAsync(new Callback<JsonNode>() {

    public void failed(UnirestException e) {
        System.out.println("The request has failed");
    }

    public void completed(HttpResponse<JsonNode> response) {
         int code = response.getStatus();
         Map<String, String> headers = response.getHeaders();
         JsonNode body = response.getBody();
         InputStream rawBody = response.getRawBody();
    }

    public void cancelled() {
        System.out.println("The request has been cancelled");
    }

});

Working with the JSON response:

HttpResponse<JsonNode> request = Unirest.get(URL)
  .header("Authorization", AUTH)
  .asJson();

// retrieve the parsed JSONObject from the response
JSONObject obj = request.getBody().getObject();

// extract fields from the object
String message = obj.getString("errormessage");
JSONArray array = myObj.getJSONArray();