Java开发中常见功能如何应用微服务架构

@RestController
public class UserController {

    @Autowired
    private UserRepository userRepository;

    @GetMapping("/users/{id}")
    public User getUser(@PathVariable("id") Long id) {
        return userRepository.findById(id).orElse(null);
    }

}

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    // 省略 getter 和 setter 方法
}

@Repository
public interface UserRepository extends JpaRepository<User, Long> {

}

@RestController
public class UserController {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private RedisTemplate<String, User> redisTemplate;

    @GetMapping("/users/{id}")
    public User getUser(@PathVariable("id") Long id) {
        String key = "user:" + id;
        User user = redisTemplate.opsForValue().get(key);
        if (user == null) {
            user = userRepository.findById(id).orElse(null);
            if (user != null) {
                redisTemplate.opsForValue().set(key, user);
            }
        }
        return user;
    }

}

// 定义消息发送者
@Component
public class MessageSender {

    @Autowired
    private RabbitTemplate rabbitTemplate;

    public void sendMessage(String message) {
        rabbitTemplate.convertAndSend("exchange", "routingKey", message);
    }

}

// 定义消息接收者
@Component
public class MessageReceiver {

    @RabbitListener(queues = "queue")
    public void receiveMessage(String message) {
        System.out.println("Received message: " + message);
    }

}

// 在微服务中使用消息发送者发送消息
@RestController
public class UserController {

    @Autowired
    private MessageSender messageSender;

    @PostMapping("/users")
    public void createUser(@RequestBody User user) {
        // 创建用户
        // ...

        // 发送消息
        messageSender.sendMessage("New user created: " + user.getName());
    }

}