https://vertx.io/docs/4.2.7/vertx-web-client/java/

vertx-web 4.3.2

WebClient client = WebClient.create(vertx);

WebClientOptions options = new WebClientOptions()
  .setUserAgent("My-App/1.2.3");
options.setKeepAlive(true);
WebClient client = WebClient.create(vertx, options);

In most cases, a Web Client should be created once on application startup and then reused. 
Otherwise you lose a lot of benefits such as connection pooling and may leak resources if instances are not closed properly.





import io.vertx.core.Vertx;
import io.vertx.core.json.JsonObject;
import io.vertx.ext.web.client.WebClient;

import java.time.LocalDateTime;

public class WebClientDemo {
    static Vertx vertx = Vertx.vertx();
    static WebClient client = WebClient.create(vertx);

    public static void main(String[] args) throws Exception {
        System.out.println("hello vertx web client");

        // Send a GET request
        System.out.println("Send a GET request");
        client
                .get(8000, "127.0.0.1", "/hello")
                .send()
                .onSuccess(response ->
                        System.out.println("success," + response.statusCode() + "," + response.bodyAsString()))
                .onFailure(err ->
                        System.out.println("error," + err));


        Thread.sleep(1000);
        // sendJsonObject
        System.out.println("sendJsonObject");
        client
                .post(8000, "127.0.0.1", "/api1")
                .sendJsonObject(
                        new JsonObject()
                                .put("id", 1)
                                .put("name", "time")
                                .put("now", LocalDateTime.now().toString())
                )
                .onSuccess(response ->
                        System.out.println("success," + response.statusCode() + "," + response.bodyAsString()))
                .onFailure(err ->
                        System.out.println("error," + err));

    }
}