如何按顺序执行 Vertx Future

Question

在我的示例项目中，我尝试在应用程序启动时进行一些初始化工作。

Java 16
顶点 4.1.0

log.info("Data initialization is starting...");
        var deleteComments = this.comments.deleteAll().onSuccess(event -> log.info("deleted comments: {}", event));
        var deletePosts = this.posts.deleteAll().onSuccess(event -> log.info("deleted posts: {}", event));
        var deleteUsers = this.authors.deleteAll().onSuccess(event -> log.info("deleted users: {}", event));

        //log.info("deleted rows: authors: {}, comments: {}, posts: {}", authorsDel, commentsDel, postDel);
        var insertData = this.authors.create("user", "user@example.com").onSuccess(
            authorId -> {
                IntStream.range(1, 5)
                    .forEach(
                        i -> {
                            this.posts.create("Dgs post #" + i, "test content of #" + i, PostStatus.DRAFT.name(), authorId).onSuccess(
                                postId -> {

                                    IntStream.range(1, new Random().nextInt(5) + 1)
                                        .forEach(c -> this.comments.create("comment #" + c, postId));
                                }
                            );

                        }
                    );
            }
        );

        var printPosts = this.posts.findAll().onSuccess(p -> log.info("post: {}", p));
        var printComments = this.comments.findAll().onSuccess(p -> log.info("comment: {}", p));
        var printAuthors = this.authors.findAll().onSuccess(p -> log.info("author: {}", p));

        deleteComments
            .flatMap(integer -> deletePosts)
            .flatMap(integer -> deleteUsers)
            .flatMap(integer -> insertData)
            .flatMap( uuid -> printPosts)
            .flatMap(postEntities -> printComments)
            .flatMap(commentEntities -> printAuthors)
            .onSuccess(event -> log.info("done"));
        log.info("done data initialization...");

但它没有按预期工作。

没有像 Reactor 这样的 then 方法。
而Future.result()会return异常而不是阻塞调用（如何以阻塞方式执行，我认为是阻塞调用）。

我找不到按顺序执行它们的有效方法。

更新:

我按照建议更改了代码。

  this.comments.deleteAll().onSuccess(event -> log.info("deleted comments: {}", event))
            .flatMap(r -> this.posts.deleteAll().onSuccess(event -> log.info("deleted posts: {}", event)))
            .flatMap(r -> this.authors.deleteAll().onSuccess(event -> log.info("deleted users: {}", event)))
            .flatMap(r -> this.authors.create("user", "user@example.com")
                .onSuccess(
                    authorId -> {
                        log.info("inserted user: {}", authorId);
                        IntStream.range(1, 5)
                            .forEach(
                                i -> {
                                    this.posts.create("Dgs post #" + i, "test content of #" + i, PostStatus.DRAFT.name(), authorId).onSuccess(
                                        postId -> {
                                            log.info("inserted post: {}", postId);
                                            IntStream.range(1, new Random().nextInt(5) + 1)
                                                .forEach(c -> this.comments.create("comment #" + c, postId)
                                                    .onSuccess(id -> log.info("inserted comment: {}", id))
                                                );
                                        }
                                    );

                                }
                            );
                    }
                )
            )
            .flatMap(r -> this.posts.findAll().onSuccess(p -> log.info("saved posts: {}", p)))
            .flatMap(r -> this.comments.findAll().onSuccess(p -> log.info("saved comments: {}", p)))
            .flatMap(r -> this.authors.findAll().onSuccess(p -> log.info("saved authors: {}", p)))
            .onSuccess(event -> log.info("done data initialization..."));

并在控制台得到如下日志。

10:20:46.699 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - Data initialization is starting...
10:20:47.768 [vert.x-eventloop-thread-1] INFO  com.example.demo.MainVerticle - HTTP server started on port 8080
10:20:47.768 [vert.x-eventloop-thread-0] INFO  i.v.c.i.l.c.VertxIsolatedDeployer - Succeeded in deploying verticle
10:20:47.918 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - deleted comments: 10
10:20:47.942 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - deleted posts: 4
10:20:47.960 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - deleted users: 1
10:20:48.022 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted user: 260fee93-cf60-408d-a3e9-f7b08ed7545a
10:20:48.047 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - saved posts: []
10:20:48.052 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted post: 57a936e2-9611-43b5-94e2-1b01069cd327
10:20:48.056 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - saved comments: []
10:20:48.067 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - saved authors: [AuthorEntity[id=260fee93-cf60-408d-a3e9-f7b08ed7545a, name=user, email=user@example.co
m, createdAt=null]]
10:20:48.092 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - done data initialization...
10:20:48.112 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted post: 534b99ae-4847-4cea-84c1-88cea87f20b7
10:20:48.117 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted post: f7dca2eb-0954-4368-b9b6-68a00f6748f2
10:20:48.120 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted post: 02e8f84f-25dd-4d69-b7f1-8c125ce35bc1
10:20:48.131 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted comment: b9bf618a-f579-48f5-96cc-51f962ca041c
10:20:48.134 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted comment: 052cfde8-627d-4cb3-8812-5543673a20ea
10:20:48.143 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted comment: 69a5dc2b-30f8-4008-90a1-e8c724336dcd
10:20:48.149 [vert.x-eventloop-thread-1] INFO  com.example.demo.DataInitializer - inserted comment: a19c2626-1546-4ba0-a663-823df08d836f

如何确保 insert 块中的所有期货在输入 print 结果之前完成。

Answer 1

这很可能是因为您的 deleteAll 和 findAll 操作并不懒惰。正因为如此，您一给他们打电话，他们就会运行ning。而不是做：

deleteComments
  .flatMap(integer -> deletePosts)
  ...

您想这样做：

deleteComments
  .flatMap(integer -> this.posts.deleteAll())
  ...

这将确保他们将运行按顺序进行。如果你想要更类似于 Reactor 的东西，你可以看看 RxJava3 extensions or mutiny bindings for Vert.x.

如何按顺序执行 Vertx Future

How to execute Vertx Future in sequential order

vert.x