常用的多线程类

常用的多线程类

创建池

 ExecutorService executor = Executors.newFixedThreadPool(4);

Executors工程类,可以提交任务。executor.submit(Callable task)

记得关闭池shutdown。

springboot对上述操作已经进行了封装

Spring Boot 中的线程池，这也太好用了！ - 腾讯云开发者社区-腾讯云 (tencent.com)

有返回值的异步操作Callable

 //Executors创建的队列容量允许的太多，将会导致oom，所以采用ThreadPoolTaskExecutor、或ThreadPoolExecutor 进行队列容量限制
//        ExecutorService executor = Executors.newFixedThreadPool(4);
//        ExecutorService executor = new ThreadPoolExecutor(10, 10,60L, TimeUnit.SECONDS, new ArrayBlockingQueue(10));
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(2);
        executor.setMaxPoolSize(2);
        executor.setKeepAliveSeconds(60);
        executor.setQueueCapacity(40);
        executor.initialize();
        Future<Integer> submit = executor.submit(() -> {
            Thread.sleep((int) 0 + (int) (Math.random() * 2));
            System.out.println(1);
            return 1;
        });
        Future<Integer> submit1 = executor.submit(() -> {
            Thread.sleep((int) 0 + (int) (Math.random() * 2));
            System.out.println(2);
            return 2;
        });
        /*
        // submit.get();
        // submit1.get(); 都不进行get数据就是不确定的顺序异步的。
         */
        /*
        submit.get();
        // submit1.get(); 进行submit数据.get,2,3
         */

        System.out.println(3);
        executor.shutdown();

同时计算成功即返回数据CompletableFuture

//每个线程做的事情
        CompletableFuture<String> C1 = CompletableFuture.supplyAsync(() -> {
            return queryCourse("1", "2");
        });
        CompletableFuture<String> C2 = CompletableFuture.supplyAsync(() -> {
            return queryCourse("2", "3");
        });
        //监听多个线程有一个成功，不阻塞，没返回也向下执行.
        CompletableFuture<Object> voidCompletableFuture = CompletableFuture.anyOf(C1, C2);


        voidCompletableFuture.thenAccept(res -> {
            System.out.println(res);
        });

(82条消息) SpringBoot 使用 CompletableFuture 实现非阻塞异步编程_流放深圳的博客-CSDN博客_springboot异步非阻塞

spring 封装的ListenableFuture 对象

executor.submitListenable()线程池中添加任务。通过调用addCallback方法可以写回调函数完成对正确与异常的数据进行处理。

setMaxPoolSize(2);
        e.setKeepAliveSeconds(60);
        e.setQueueCapacity(Integer.MAX_VALUE);
        e.initialize();
        e.submitListenable(() -> {

            // 休息 5 秒，模拟工作的情况
            TimeUnit.SECONDS.sleep(5);
            // 通过抛出 RuntimeException 异常来模拟异常
//            throw new RuntimeException("出现异常");
            return 1;

        }).addCallback(data -> System.out.println("success,result = " + data), ex -> System.out.println("**异常信息**：" + ex));
        e.shutdown();