MyFirstVerticle.java

package io.vertx.blog.first;

import java.io.File;
import java.util.Scanner;
import io.vertx.core.AbstractVerticle;
import io.vertx.core.Future;

public class MyFirstVerticle extends AbstractVerticle {
  static String data;
  final static int BLOCK_SIZE = 250000;

  @Override
  public void start(Future<Void> fut) {
    String filename = "./start.json";

    System.out.println(filename);

    try {
       data = new Scanner(new File(filename)).useDelimiter("\\Z").next();
    } catch(Exception fnfe) {
       System.exit(1);
    }

    vertx
        .createHttpServer()
        .requestHandler(r -> {
          r.response().setChunked(true).headers().set("content-type", (new Integer(data.length())).toString());
          for(int i = 0; i < data.length(); i += BLOCK_SIZE) {
            int end = (i + BLOCK_SIZE > data.length()) ? data.length() - 1 : i + BLOCK_SIZE; 
            r.response().write(data.substring(i, end), "UTF-8"); 
          }
          r.response().end();
        })
        .listen(3000, result -> {
          if (result.succeeded()) {
            fut.complete();
          } else {
            fut.fail(result.cause());
          }
        });
  }
}