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spring-boot - Schdulers.elastic 不在 Reactor 中创建新线程

问题描述

我正在尝试创建一个流，其中通量发出 10 个项目，每个项目并行，每个项目休眠 1 秒。由于每个项目都在单独的线程上发布，我希望整个过程需要 1 秒。但是日志显示它需要 10 秒。

我尝试将 subscribeOn 更改为 publishOn，映射到 doOnNext。但它们似乎都不起作用。

我是 Reactor 的新手，正在尝试了解我哪里出错了。非常感激任何的帮助。谢谢

    public void whenIsANewThreadCreated() {
        Flux.range(1,10)
                .publishOn(Schedulers.elastic())
                .map(count -> {
                    logger.info(Thread.currentThread().getName() + " - Sleeping for 1s" + " with count: " + count);
                    try {
                        Thread.sleep(1_000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    return count;
                })
        .blockLast();
    }

2020-03-30 16:17:29.799  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 1
2020-03-30 16:17:30.802  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 2
2020-03-30 16:17:31.804  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 3
2020-03-30 16:17:32.805  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 4
2020-03-30 16:17:33.806  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 5
2020-03-30 16:17:34.808  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 6
2020-03-30 16:17:35.809  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 7
2020-03-30 16:17:36.811  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 8
2020-03-30 16:17:37.812  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 9
2020-03-30 16:17:38.814  INFO 15744 --- [      elastic-2] com.example.demo.DemoApplicationTests    : elastic-2 - Sleeping for 1s with count: 10

标签： spring-bootreactive-programmingproject-reactorspring-reactivespring-reactor

解决方案

您必须首先通过调用parallel方法创建一个并行通量，并且您必须使用它runOn来实现并行性。

Flux.range(1,10)
    .parallel()
    .runOn(Schedulers.elastic())
    .map(count -> {
        System.out.println(Thread.currentThread().getName() + " - Sleeping for 1s" + " with count: " + count);
        try {
            Thread.sleep(1_000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return count;
    }).subscribe();
  • 不鼓励使用Schedulers.boundedElastic()as usingScheduler.elastic()
  • parallel默认情况下将根据您的 CPU 内核创建线程。如果您想使用更多线程parallel(10)- 我认为这就是您想要看到的。

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