Http Request and Http Response

In previous posts we figured out how to send Http requests and get Http responses with Apache HttpComponents and RESTEasy

Today we’re going to have some fun with OkHttp.

OkHttp Maven dependency

        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>3.11.0</version>
        </dependency>

GET request example

Now we have to instantiate OkHttpClient

        OkHttpClient client = new OkHttpClient();

and build Request.

        String url = "https://user-service.mycompany.com";
        Request request = new Request.Builder()
                .url(url)
                .build();

If we need to add a Http Header

        Request request = new Request.Builder()
                .addHeader("Accept", "application/json")
                .url(url)
                .build();

POST request example

For POST the request will be

        RequestBody body = RequestBody
                .create(MediaType.parse("application/json"), jsonString);
        Request request = new Request.Builder()
                .post(body)
                .addHeader("Accept", "application/json")
                .url(url)
                .build();

PUT request example

        RequestBody body = RequestBody.create(MediaType
                .parse("application/json"), jsonString);
        Request request = new Request.Builder()
                .put(body)
                .addHeader("Accept", "application/json")
                .url(url)
                .build();

DELETE request example

        RequestBody body = RequestBody
                .create(MediaType.parse("application/json"), jsonString);
        Request request = new Request.Builder()
                .delete()
                .addHeader("Accept", "application/json")
                .url(url)
                .build();

Http Response

Now we can make a call and get the Http response

        Response response = client.newCall(request).execute();

The response body as a string

        String responseBody = response.body().string();

The response body to the object

        Gson gson = new Gson();
        User user = gson.fromJson(responseBody, User.class);

See more about How to convert JSON to Java Object.

The response code

        int responseCode = response.code();

That’s pretty much it.

OkHttp is the easy to use Http client that covers most of basic needs

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