SpringBoot中的异步执行方法详解

@ConditionalOnClass({ThreadPoolTaskExecutor.class})   // 代表如果容器中有这个类,就不在创建
@AutoConfiguration
@EnableConfigurationProperties({TaskExecutionProperties.class})  // 配置文件
public class TaskExecutionAutoConfiguration {
    // 应用程序任务执行器任务名称 applicationTaskExecutor
    public static final String APPLICATION_TASK_EXECUTOR_BEAN_NAME = "applicationTaskExecutor";

    public TaskExecutionAutoConfiguration() {
    }

    @Bean
    @ConditionalOnMissingBean
    public TaskExecutorBuilder taskExecutorBuilder(TaskExecutionProperties properties, ObjectProvider<TaskExecutorCustomizer> taskExecutorCustomizers, ObjectProvider<TaskDecorator> taskDecorator) {
        Pool pool = properties.getPool();
        TaskExecutorBuilder builder = new TaskExecutorBuilder();
        builder = builder.queueCapacity(pool.getQueueCapacity());
        builder = builder.corePoolSize(pool.getCoreSize());
        builder = builder.maxPoolSize(pool.getMaxSize());
        builder = builder.allowCoreThreadTimeOut(pool.isAllowCoreThreadTimeout());
        builder = builder.keepAlive(pool.getKeepAlive());
        Shutdown shutdown = properties.getShutdown();
        builder = builder.awaitTermination(shutdown.isAwaitTermination());
        builder = builder.awaitTerminationPeriod(shutdown.getAwaitTerminationPeriod());
        builder = builder.threadNamePrefix(properties.getThreadNamePrefix());
        Stream var10001 = taskExecutorCustomizers.orderedStream();
        var10001.getClass();
        builder = builder.customizers(var10001::iterator);
        builder = builder.taskDecorator((TaskDecorator)taskDecorator.getIfUnique());
        return builder;
    }

    @Lazy
    @Bean(
        name = {"applicationTaskExecutor", "taskExecutor"}
    )
    @ConditionalOnMissingBean({Executor.class})
    public ThreadPoolTaskExecutor applicationTaskExecutor(TaskExecutorBuilder builder) {
        return builder.build();
    }

public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
		implements AsyncListenableTaskExecutor, SchedulingTaskExecutor {

	private final Object poolSizeMonitor = new Object();

	private int corePoolSize = 1;

	private int maxPoolSize = Integer.MAX_VALUE;

	private int keepAliveSeconds = 60;

	private int queueCapacity = Integer.MAX_VALUE;

	private boolean allowCoreThreadTimeOut = false;

	private boolean prestartAllCoreThreads = false;
	
	//       ......  ......................省略
	// 创建代码
	@Override
	protected ExecutorService initializeExecutor(
			ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {

		BlockingQueue<Runnable> queue = createQueue(this.queueCapacity);

		ThreadPoolExecutor executor;
		if (this.taskDecorator != null) {
            // 还是 new ThreadPoolExecutor
			executor = new ThreadPoolExecutor(
					this.corePoolSize, this.maxPoolSize, this.keepAliveSeconds, TimeUnit.SECONDS,
					queue, threadFactory, rejectedExecutionHandler) {
				@Override
				public void execute(Runnable command) {
					Runnable decorated = taskDecorator.decorate(command);
					if (decorated != command) {
						decoratedTaskMap.put(decorated, command);
					}
					super.execute(decorated);
				}
			};
		}
		else {
			executor = new ThreadPoolExecutor(
					this.corePoolSize, this.maxPoolSize, this.keepAliveSeconds, TimeUnit.SECONDS,
					queue, threadFactory, rejectedExecutionHandler);
		}

		if (this.allowCoreThreadTimeOut) {
			executor.allowCoreThreadTimeOut(true);
		}
		if (this.prestartAllCoreThreads) {
			executor.prestartAllCoreThreads();
		}

		this.threadPoolExecutor = executor;
		return executor;
	}

// 注入
@Autowired
private ThreadPoolTaskExecutor executor;

@Test
public void testThreadPool(){
    System.out.println(executor);
    System.out.println("默认前缀:"+executor.getThreadNamePrefix());
    System.out.println("默认核心线程数:"+executor.getCorePoolSize());
    System.out.println("默认最大线程数:"+executor.getMaxPoolSize());
    System.out.println("当前活跃线程数:"+executor.getActiveCount());
    System.out.println("临时线程空闲时间:"+executor.getKeepAliveSeconds());
    System.out.println("队列最大值:"+executor.getQueueCapacity());
    System.out.println("队列数量:"+executor.getQueueSize());
}

@Slf4j
@Configuration
public class PromotionConfig {

    @Bean
    public Executor generateExchangeCodeExecutor(){
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        // 1.核心线程池大小
        executor.setCorePoolSize(2);
        // 2.最大线程池大小
        executor.setMaxPoolSize(5);
        // 3.队列大小
        executor.setQueueCapacity(200);
        // 4.线程名称
        executor.setThreadNamePrefix("exchange-code-handler-");
        // 5.拒绝策略
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.initialize();
        return executor;
    }
}

    @Override
    @Async("generateExchangeCodeExecutor")
    public void asyncGenerateCode(Coupon coupon) {
    		......
    }