ServerClientCode.java

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

import java.net.URI;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpClient;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class ServerClientCode {
    private static final HttpClient CLIENT = HttpClient.newHttpClient();
    private static final Gson GSON = new Gson();
    static List<Integer> howmanyidies = new ArrayList<>();


    public static User postRequest(URI uri, User user) throws Exception {
        final String jsonRequest = GSON.toJson(user);
        System.out.println(jsonRequest);

        HttpRequest postRequest = HttpRequest.newBuilder()
                .uri(uri)
                .POST(HttpRequest.BodyPublishers.ofString(jsonRequest))
                .build();

        HttpResponse<String> postResponse = CLIENT.send(postRequest, HttpResponse.BodyHandlers.ofString());
        System.out.println(postResponse.body());
        return GSON.fromJson(postResponse.body(), User.class);

    }

    public static User getRequest(URI uri) throws Exception {

        HttpRequest getRequest = HttpRequest.newBuilder()
                .uri(uri)
                .build();

        HttpResponse<String> getResponse = CLIENT.send(getRequest, HttpResponse.BodyHandlers.ofString());
        System.out.println(getResponse.body());
        return GSON.fromJson(getResponse.body(), User.class);
    }

    public static User deleteRequest(URI uri) throws Exception {

        HttpRequest deleteRequest = HttpRequest.newBuilder()
                .uri(uri)
                .DELETE()
                .build();

        HttpResponse<String> deleteResponse = CLIENT.send(deleteRequest, HttpResponse.BodyHandlers.ofString());
        return GSON.fromJson(deleteResponse.body(), User.class);
    }

    public static List<User> showAllUsers(URI uri) throws Exception {

        HttpRequest getAllRequest = HttpRequest.newBuilder()
                .uri(uri)
                .build();
        HttpResponse<String> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofString());
        System.out.println(getAllResponse.body());
        return GSON.fromJson(getAllResponse.body(), new TypeToken<List<User>>() {
        }.getType());
    }

    public static User getUserById(String url, int id) throws Exception {
        HttpRequest getAllRequest = HttpRequest.newBuilder()
                .uri(URI.create(url + id))
                .build();
        HttpResponse<String> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofString());
        System.out.println(getAllResponse.body());
        return GSON.fromJson(getAllResponse.body(), User.class);
    }
//     to get list of usernames
//    public static void getUserNames() throws Exception {
//        System.out.println("Usernames:");
//        for (int i = 1; i <= 10; i++) {
//            HttpRequest getAllRequest = HttpRequest.newBuilder()
//                    .uri(new URI("https://jsonplaceholder.typicode.com/users/" + i))
//                    .build();
//
//            HttpResponse<String> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofString());
//            final User user = GSON.fromJson(getAllResponse.body(), User.class);
//            System.out.println(user.getUsername());
//        }
//  }

    public static List<User> getUserByUserName(String url, String username) throws Exception {

        HttpRequest getAllRequest = HttpRequest.newBuilder()
                .uri(URI.create(url + username))
                .build();
        HttpResponse<String> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofString());
        System.out.println(getAllResponse.body());
        return GSON.fromJson(getAllResponse.body(), new TypeToken<List<User>>() {
        }.getType());
    }

    public static List<Task> openUserTasks(String url, int userId) throws Exception {

        HttpRequest getAllRequest = HttpRequest.newBuilder()
                .uri(URI.create(url + userId + "/todos"))
                .build();
        HttpResponse<String> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofString());
        List<Task> tasks = GSON.fromJson(getAllResponse.body(), new TypeToken<List<Task>>() {
        }.getType());

        return tasks.stream()
                .filter(task -> !task.isCompleted())
                .collect(Collectors.toList());
    }

    //method getting last post ID for next method (userComments)
    public static void lastPostId(URI uri) throws Exception {
        HttpRequest getAllRequest = HttpRequest.newBuilder()
                .uri(uri)
                .build();
        HttpResponse<String> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofString());
        List<Posts> posts = GSON.fromJson(getAllResponse.body(), new TypeToken<List<Posts>>() {
        }.getType());

        howmanyidies = posts.stream()
                .sorted(Comparator.comparing(Posts::getId).reversed())
                .map(Posts::getId)
                .limit(1)
                .collect(Collectors.toList());
    }

    public static void userComments(String url) throws Exception {

        ServerClientCode.lastPostId(URI.create("https://jsonplaceholder.typicode.com/users/1/posts"));
        int id = howmanyidies.get(0);
        int userId = 1;
        HttpRequest getAllRequest = HttpRequest.newBuilder()
                .uri(URI.create(url + id + "/comments"))
                .build();
        String filename = "user-"+userId+"-post-"+id+"-comments.json";
        HttpResponse<Path> getAllResponse = CLIENT.send(getAllRequest, HttpResponse.BodyHandlers.ofFile(Paths.get(filename)));
        System.out.println(getAllResponse.body());
    }
}