Spring Boot @Transactional 在 @Service 类（而不是控制器）上不起作用

Question

我认为将@Transactional 注释放在服务层类上而不是控制器上是最佳实践（参见 f.e. Why we shouldn't make a Spring MVC controller @Transactional?）。但这不适用于我的 Spring Boot 应用程序。这是为什么呢？

控制器中的registerAction 方法（参见下面的代码）执行多个服务调用。当 f.e. mailService.sendActivationMail(...) 失败，我想从 userService.registerUser(...) 调用中回滚插入的用户。我是否需要将@Transactional 注释放在控制器类上？

当在控制器类上设置@Transactional 注解时，我的 Spring Boot 应用程序正确使用事务：

AuthController.java

@RestController
@RequestMapping("/api/auth")
@Transactional
public class AuthController {

    @Autowired
    private UserService userService;

    @Autowired
    private ProfileService profileService;

    @Autowired
    private MailService mailService;

    @RequestMapping(path = "register", method = RequestMethod.POST)
    public Profile registerAction(@Valid @RequestBody Registration registration) {
        ApiUser user = userService.registerUser(registration);
        Profile profile = profileService.createProfile(user, registration);

        mailService.sendActivationMail(user);

        return profile;
    }

}

但是当 @Transactional 注解设置在服务类上（而不是控制器上）时，事务不起作用：

UserService.java

@Service
@Transactional
public class UserService {

    @Autowired
    private ApiUserRepository userRepository;

    public ApiUser registerUser(Registration registration) {
        ...
        userRepository.save(user);
        ...
    }

}

---

我的配置类：

SpringApiApplication.java

@SpringBootApplication
public class SpringApiApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringApiCommonApplication.class, args);
    }
}

ApiConfiguration.java

@Configuration
@EnableJpaAuditing
@EnableTransactionManagement
public class ApiConfiguration {
    @Autowired
    private ApiProperties properties;

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    public UsernameCanonicalizer usernameCanonicalizer() {
        return new UsernameCanonicalizer();
    }

    @Bean
    public EmailCanonicalizer emailCanonicalizer() {
        return new EmailCanonicalizer();
    }

    @Bean
    public ApiTokenHandler activationTokenHandler() {
        return new StandardApiTokenHandler(properties.getActivationTokenDuration());
    }
}

Answer 1

@M.Deinum 让我走上了正轨。 Spring（引导）不会像其他框架那样自动将您的控制器调用包装在事务中。因此，您必须向控制器添加@Transactional 注释，或者将代码从控制器类移动到服务类。

将代码从控制器类移动到服务类是更好的做法，因为（除其他外）使代码更易于测试。所以我就是这么做的。

AuthenticationService.java

@Service
public class AuthenticationService {
    @Autowired
    private UserManager userManager;

    @Autowired
    private ProfileManager profileManager;

    @Autowired
    private MailManager mailManager;

    @Transactional
    public Profile registerUser(Registration registration) {
        ApiUser user = userManager.registerUser(registration);
        Profile profile = profileManager.createProfile(user, registration);

        mailManager.sendActivationMail(user);

        return profile;
    }

    ...
}

AuthController.java

@RestController
@RequestMapping("/api/auth")
public class AuthController {
    @Autowired
    private AuthenticationService authenticationService;

    @RequestMapping(path = "register", method = RequestMethod.POST)
    @ApiOperation(value = "Registers a user")
    public Profile register(@Valid @RequestBody Registration registration) {
        return authenticationService.registerUser(registration);
    }

    ...
}

Answer 2

您可以将@Transactional 注解放在接口定义、接口上的方法、类定义或类上的公共方法之前。然而，仅仅存在@Transactional 注释并不足以激活事务行为。

@Transactional 注释只是元数据，可以被一些运行时基础设施（@Transactional-aware）使用，并且可以使用元数据来配置具有事务行为的适当 bean。

在前面的示例中，<tx:annotation-driven/> 元素开启了事务行为。

    // Below is the service class that we want to make transactional
    @Transactional
    public class DefaultEmployeeService implements EmployeeService {

        void insertEmployee(Employee Employee);

        void updateEmployee(Employee Employee);
    }

    XML Configuration:
    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" ...>

        <!-- this is the service object that we want to make transactional -->
        <bean id="employeeService" class="service.DefaultEmployeeService"/>

        <!-- enable the configuration of transactional behavior based on annotations -->
        <tx:annotation-driven transaction-manager="txManager"/>

        <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <!-- (this dependency is defined somewhere else) -->
            <property name="dataSource" ref="dataSource"/>
        </bean>
    </beans>

你可以尝试的几点：

1. 执行上述所有配置。
2. 从 Controller 中移除 @Transactional 配置。
3. 将 Service 对象与事务管理器 bean 一起引用。

更多详情：http://docs.spring.io/spring/docs/current/spring-framework-reference/html/transaction.html