前言：

关于多线程的异步处理，由于项目的需求有个方法需要使用异步的方法来调用，方法是调用外部的接口，执行时间会比较长导致的没有办法同步拿去到结果，所以需要写一个异步线程的方法进行该接口的调用，下面是一个案例以及自己测试的异步结果的情况；

第一步：需要是项目启动的初始化启动异步的配置处理

第二步：需要创建config进行配置相关线程池的处理

@Configuration
public class SpringBootAsyncConfig {
    private static final Logger LOGGER = LoggerFactory.getLogger(SpringBootMvcConfig.class);
    @Value("${spring.async.thread.pool.core-pool-size}")
    private int corePoolSize = 10;
    @Value("${spring.async.thread.pool.max-pool-size}")
    private int maxPoolSize = 1000;
    @Value("${spring.async.thread.pool.queue-capacity}")
    private int queueCapacity = 1000;
    @Value("${spring.async.thread.pool.keep-alive-seconds}")
    private int keepAliveSeconds = 600;

    public SpringBootAsyncConfig() {
    }

    @Bean({"asyncThreadPool"})
    public TaskExecutor taskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(this.corePoolSize);
        executor.setMaxPoolSize(this.maxPoolSize);
        executor.setQueueCapacity(this.queueCapacity);
        executor.setKeepAliveSeconds(this.keepAliveSeconds);
        executor.setThreadNamePrefix("AsyncThreadPool-");
        executor.setRejectedExecutionHandler(new AbortPolicy());
        executor.setTaskDecorator(new TaskDecorator() {
            public Runnable decorate(Runnable runnable) {
                Map<String, Object> captureMapData = DataCaptureContext.getMapData();
                Map<String, String> mdcMap = MDC.getCopyOfContextMap();
                return () -> {
                    try {
                        if (mdcMap != null) {
                            MDC.setContextMap(mdcMap);
                        }

                        if (captureMapData != null) {
                            DataCaptureContext.setMapData(captureMapData);
                        }

                        runnable.run();
                    } finally {
                        MDC.clear();
                        DataCaptureContext.removeMapData();
                    }

                };
            }
        });
        executor.initialize();
        return executor;
    }

    @Bean({"springSessionRedisTaskExecutor"})
    public ThreadPoolTaskExecutor springSessionRedisTaskExecutor() {
        ThreadPoolTaskExecutor springSessionRedisTaskExecutor = new ThreadPoolTaskExecutor();
        springSessionRedisTaskExecutor.setCorePoolSize(10);
        springSessionRedisTaskExecutor.setMaxPoolSize(10);
        springSessionRedisTaskExecutor.setKeepAliveSeconds(600);
        springSessionRedisTaskExecutor.setQueueCapacity(1000);
        springSessionRedisTaskExecutor.setThreadNamePrefix("Spring session redis executor thread: ");
        springSessionRedisTaskExecutor.setRejectedExecutionHandler(new DiscardPolicy());
        springSessionRedisTaskExecutor.initialize();
        return springSessionRedisTaskExecutor;
    }

    @Bean({"bankInstructionTaskExecutor"})
    public ThreadPoolTaskExecutor bankInstructionTaskExecutor() {
        ThreadPoolTaskExecutor bankInstructionTaskExecutor = new ThreadPoolTaskExecutor();
        bankInstructionTaskExecutor.setCorePoolSize(20);
        bankInstructionTaskExecutor.setMaxPoolSize(20);
        bankInstructionTaskExecutor.setKeepAliveSeconds(1800);
        bankInstructionTaskExecutor.setQueueCapacity(20);
        bankInstructionTaskExecutor.setThreadNamePrefix("bank instruction task  executor thread: ");
        bankInstructionTaskExecutor.setRejectedExecutionHandler(new DiscardPolicy());
        bankInstructionTaskExecutor.setTaskDecorator(new TaskDecorator() {
            public Runnable decorate(Runnable runnable) {
                Map<String, Object> captureMapData = DataCaptureContext.getMapData();
                Map<String, String> mdcMap = MDC.getCopyOfContextMap();
                return () -> {
                    try {
                        if (mdcMap != null) {
                            MDC.setContextMap(mdcMap);
                        }

                        if (captureMapData != null) {
                            DataCaptureContext.setMapData(captureMapData);
                        }

                        runnable.run();
                    } finally {
                        MDC.clear();
                        DataCaptureContext.removeMapData();
                    }

                };
            }
        });
        bankInstructionTaskExecutor.initialize();
        return bankInstructionTaskExecutor;
    }

    @Bean({"instructionStatusUpdateTaskExecutor"})
    public ThreadPoolTaskExecutor instructionStatusUpdateTaskExecutor() {
        ThreadPoolTaskExecutor bankInstructionTaskExecutor = new ThreadPoolTaskExecutor();
        bankInstructionTaskExecutor.setCorePoolSize(20);
        bankInstructionTaskExecutor.setMaxPoolSize(20);
        bankInstructionTaskExecutor.setKeepAliveSeconds(1800);
        bankInstructionTaskExecutor.setQueueCapacity(20);
        bankInstructionTaskExecutor.setThreadNamePrefix("instruction status update executor thread: ");
        bankInstructionTaskExecutor.setRejectedExecutionHandler(new DiscardPolicy());
        bankInstructionTaskExecutor.setTaskDecorator(new TaskDecorator() {
            public Runnable decorate(Runnable runnable) {
                Map<String, Object> captureMapData = DataCaptureContext.getMapData();
                Map<String, String> mdcMap = MDC.getCopyOfContextMap();
                return () -> {
                    try {
                        if (mdcMap != null) {
                            MDC.setContextMap(mdcMap);
                        }

                        if (captureMapData != null) {
                            DataCaptureContext.setMapData(captureMapData);
                        }

                        runnable.run();
                    } finally {
                        MDC.clear();
                        DataCaptureContext.removeMapData();
                    }

                };
            }
        });
        bankInstructionTaskExecutor.initialize();
        return bankInstructionTaskExecutor;
    }
}

第三步：在调用异步方法的时候需要进行注解的标注该方法是异步的方法

第四步：异步方法的调用执行情况如下

第五步：异步方法的调用情况二

总结：

需要注意的点有三个，也就是分为三种情况：

1. 避免同步方法里面调用异步的方法，比如说在controller里面的类直接调用本controller里面的异步方法，这个时候是不会产生异步的效果的，还是会顺序的执行。
2. 如果说在controller里面调用service里面的同步方法的话，同步方法里面有调用其他的异步方法，这个时候也会认为是同步的方法，也会顺序的执行，异步没有效果，也不会新开线程进行处理的。
3. 只有在controller里面直接调用service里面的异步方法才会产生异步的效果。

综上所述，异步方法要正确的时候才会达到想要的结果，否则的话容易同步方法里面调用异步方法，导致异步方法没有效果，闹出笑话来。始终坚持学习，始终去实践测试代码，看一下执行的结果才能正确写出想要的代码，程序员一定要做到知其然知其所以然，共勉。