了解Spring的Web反应框架

Question

UserController：

@RequestMapping(value = "/user", method = RequestMethod.POST)
public Mono<ResponseEntity<Integer>> createUser(@RequestBody ImUser user) {
    return Mono.just(user)
            .map(it -> {
                logger.debug("Receiving request on thread: " + Thread.currentThread().getName());
                return it;
            })
            .map(userService::create)
            .map(it -> {
                logger.debug("Sending response on thread: " + Thread.currentThread().getName());
                return ResponseEntity.status(HttpStatus.CREATED).body(it);
            })
            .mapError(DuplicateKeyException.class, e -> new SomeSpecialException(e.getMessage(), e));
}

用户服务：

public int create(ImUser user) {
    return Mono.just(user)
            .subscribeOn(Schedulers.elastic())
            .map(u -> {
                logger.debug("UserService thread: " + Thread.currentThread().getName());
                return imUserDao.insertUser(u);
            })
            .block();
}

用户道：

@Transactional(propagation = Propagation.REQUIRED, isolation = Isolation.READ_COMMITTED, rollbackFor = Exception.class)
public int insertUser(ImUser user) {
    logger.debug("Insert DB on thread: " + Thread.currentThread().getName());
    return dsl.insertInto(IM_USER,IM_USER.VERSION, IM_USER.FIRST_NAME, IM_USER.LAST_NAME, IM_USER.BIRTHDATE, IM_USER.GENDER)
            .values(1, user.getFirstName(), user.getLastName(), user.getBirthdate(), user.getGender())
            .returning(IM_USER.ID)
            .fetchOne()
            .getId();
}

20:57:21,384 DEBUG         admin.UserController| Receiving request on thread: reactor-http-server-epoll-7
20:57:21,387 DEBUG            admin.UserService| UserService thread: elastic-2
20:57:21,391 DEBUG        admin.ExtendedUserDao| Insert DB on thread: elastic-2
20:57:21,393 DEBUG         tools.LoggerListener| Executing query          
...
20:57:21,401 DEBUG              tools.StopWatch| Finishing                : Total: 9.355ms, +3.355ms
20:57:21,409 DEBUG         admin.UserController| Sending response on thread: reactor-http-server-epoll-7

return userService.create(user)
            .map(it -> ResponseEntity.status(HttpStatus.CREATED).body(it))
            .mapError(DuplicateKeyException.class, e -> new SomeSpecialException(e.getMessage(), e));

但我无法实现这一点，并保持事情在正确的线程中运行。有什么方法可以在我的代码中实现这一点吗？

任何帮助都将不胜感激。谢了！

Answer 1

服务和控制器
服务阻塞的事实是有问题的，因为在控制器中，您从映射中调用阻塞方法，而该映射没有在单独的线程上移动。这有可能阻塞所有控制器。

相反，您可以从userservice#create返回一个mono（删除末尾的块()）。由于服务确保Dao方法调用是隔离的，因此问题较少。从那里，不需要在控制器中执行mono.just(user):只需调用create并直接在结果mono上启动链接操作符：

@RequestMapping(value = "/user", method = RequestMethod.POST)
public Mono<ResponseEntity<Integer>> createUser(@RequestBody ImUser user) {
    //this log as you saw was executed in the same thread as the controller method
    logger.debug("Receiving request on thread: " + Thread.currentThread().getName());
    return userService.create(user)
        .map(it -> {
            logger.debug("Sending response on thread: " + Thread.currentThread().getName());
            return ResponseEntity.status(HttpStatus.CREATED).body(it);
        })
        .mapError(DuplicateKeyException.class, e -> new SomeSpecialException(e.getMessage(), e));
}

日志记录
注意，如果您想记录某些内容，有两个比执行映射并返回它更好的选项：