SpringBoot实现异步事件Event详解

public void registerUser(AddUserRequest request){
	//插入用户
	userService.insertUser(request);
}

public void registerUser(AddUserRequest request){
	//插入用户
	User user = convertToUser(request)
	userService.insertUser(user);
	//发邮件
	sendEmail(user);
	//发放优惠券
	sendCouponToUser(user);
}

@Data
public class RegisterUserEvent {
    /**
     * 用户id
     */
    private Integer userId;
    /**
     * 用户名
     */
    private String userName;
}

@RestController
@Api(tags="测试前端控制器")
@RequiredArgsConstructor
public class TestController {
    private final TestService testService;

    @ApiOperation(value="模拟注册用户功能的发送事件", notes="\n 开发者：")
    @PostMapping("/sendEvent")
    public JsonResult sendEvent(){
        testService.sendEvent();
        return JsonResult.success();
    }
}

/**
 * @author zhengbingyuan
 * @date 2023/2/6
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class TestService {
    private final ApplicationEventPublisher eventPublisher;

    /**
     * 模拟一个注册用户的功能
     */
    @Transactional(rollbackFor = Exception.class)
    public void sendEvent() {
        log.info("开始注册用户....");
        UserDto dto = saveUser();

        RegisterUserEvent userEvent = new RegisterUserEvent();
        userEvent.setUserId(dto.getId());
        userEvent.setUserName(dto.getUserName());
        eventPublisher.publishEvent(userEvent);
    }

    private UserDto saveUser() {
        int id = 1;
        String userName = "超人";
        log.info("保存用户id: {},name:{}",id,userName);
        UserDto dto = new UserDto();
        dto.setId(id);
        dto.setUserName(userName);
        return dto;
    }


}

/**
 * @author zhengbingyuan
 * @date 2023/2/6
 */
@Slf4j
@Component
public class RegisterUserEventListener {
    @EventListener
    public void processSendCouponToUser(RegisterUserEvent event){
        log.info("发放优惠券给用户：{}",event.getUserName());
    }


    @EventListener
    public void processSendEmailToUser(RegisterUserEvent event){
        log.info("发放邮件给用户：{}",event.getUserName());
    }
}

@Override
public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) {
	ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event));
	Executor executor = getTaskExecutor();
	for (ApplicationListener<?> listener : getApplicationListeners(event, type)) {
		if (executor != null) {
			//线程池调用
			executor.execute(() -> invokeListener(listener, event));
		}
		else {
			//直接调用
			invokeListener(listener, event);
		}
	}
}

protected void initApplicationEventMulticaster() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
			this.applicationEventMulticaster =
					beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
			if (logger.isTraceEnabled()) {
				logger.trace("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
			}
		}
		else {
			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
			if (logger.isTraceEnabled()) {
				logger.trace("No '" + APPLICATION_EVENT_MULTICASTER_BEAN_NAME + "' bean, using " +
						"[" + this.applicationEventMulticaster.getClass().getSimpleName() + "]");
			}
		}
	}

/**
 * @author zhengbingyuan
 * @date 2023/2/6
 */
@Configuration
@RequiredArgsConstructor
public class AsyncEventConfiguration {
    @Bean
    public SimpleApplicationEventMulticaster applicationEventMulticaster(BeanFactory beanFactory) {
        SimpleApplicationEventMulticaster applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
        //设置线程池
        applicationEventMulticaster.setTaskExecutor(eventExecutor());
        return applicationEventMulticaster;
    }

    @Bean
    public TaskExecutor eventExecutor() {
        ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
        //核心线程数
        int corePoolSize = 5;
        threadPoolTaskExecutor.setCorePoolSize(corePoolSize);
        //最大线程数
        int maxPoolSize = 10;
        threadPoolTaskExecutor.setMaxPoolSize(maxPoolSize);
        //队列容量
        int queueCapacity = 10;
        threadPoolTaskExecutor.setQueueCapacity(queueCapacity);
        //拒绝策略
        threadPoolTaskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.AbortPolicy());
        //线程名前缀
        String threadNamePrefix = "eventExecutor-";
        threadPoolTaskExecutor.setThreadNamePrefix(threadNamePrefix);
        threadPoolTaskExecutor.setWaitForTasksToCompleteOnShutdown(true);
        // 使用自定义的跨线程的请求级别线程工厂类19
        int awaitTerminationSeconds = 5;
        threadPoolTaskExecutor.setAwaitTerminationSeconds(awaitTerminationSeconds);
        threadPoolTaskExecutor.initialize();
        return threadPoolTaskExecutor;
    }
}