SpringBoot基于AOP的本地/远程调用动态路由实践指南

// **统一接口** = 本地实现 + 远程 Feign 共用
public interface UserService {
    User getUserById(Long id);
    List<User> listAllUsers();
    User saveUser(User u);
    void updateUser(User u);
    void deleteUser(Long id);
}

@Service
@ConditionalOnProperty(name = "service.mode", havingValue = "local", matchIfMissing = true)
public class UserServiceLocalImpl implements UserService {

    @Autowired
    private UserRepository repo;   // 直连数据库，不走网络

    @Override
    public User getUserById(Long id) {
        return repo.findById(id).orElse(null);
    }

    @Override
    public List<User> listAllUsers() {
        return repo.findAll();
    }

    /* 其余方法省略 */
}

// 1. 声明式 HTTP 客户端
@FeignClient(name = "user-service", fallback = UserServiceFallback.class)
public interface UserServiceFeignClient {

    @GetMapping("/api/users/{id}")
    User getUserById(@PathVariable("id") Long id);

    @GetMapping("/api/users")
    List<User> listAllUsers();

    @PostMapping("/api/users")
    User saveUser(@RequestBody User u);

    @PutMapping("/api/users")
    void updateUser(@RequestBody User u);

    @DeleteMapping("/api/users/{id}")
    void deleteUser(@PathVariable("id") Long id);
}
@Service
@ConditionalOnProperty(name = "service.mode", havingValue = "remote")
public class UserServiceRemoteImpl implements UserService {

    @Autowired
    private UserServiceFeignClient feignClient;   // 代理，真正发 HTTP

    @Override
    public User getUserById(Long id) {
        return feignClient.getUserById(id);
    }

    /* 其余方法省略 */
}

@Configuration
@EnableFeignClients(basePackages = "com.example.feign")
public class ServiceAutoConfiguration {

    @Bean
    @ConditionalOnProperty(name = "service.mode", havingValue = "remote")
    public UserService userServiceRemote(UserServiceFeignClient client) {
        return new UserServiceRemoteImpl(client);
    }

    @Bean
    @ConditionalOnProperty(name = "service.mode", havingValue = "local", matchIfMissing = true)
    public UserService userServiceLocal(UserRepository repo) {
        return new UserServiceLocalImpl(repo);
    }
}

# application.yml
service:
  mode: local   # 改成 remote 秒变微服务

service:
  user: local
  order: remote
  product: local

@Aspect
@Component
public class SmartRoutingAspect {
    @Around("@annotation(SmartRouting)")
    public Object route(ProceedingJoinPoint pjp) {
        // 统计 RT、错误率，实时计算 local vs remote 分值
        boolean goLocal = loadBalancingService.shouldGoLocal(pjp.getSignature());
        return goLocal ? pjp.proceed() : feignInvoke(pjp);
    }
}