<!-- Spring Boot Starter Data Redis -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

@Configuration
public class RedisConfig {
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        return template;
    }
}

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Idempotent {
    String keyPrefix() default "idempotent:";
    long expireTime() default 5000; // 过期时间（毫秒）
}

@Aspect
@Component
public class IdempotentAspect {
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;

    @Around("@annotation(idempotent)")
    public Object handleIdempotent(ProceedingJoinPoint joinPoint, Idempotent idempotent) throws Throwable {
        String uniqueKey = generateUniqueKey(joinPoint, idempotent.keyPrefix());
        long expireTime = idempotent.expireTime();

        // 尝试设置Redis Key（原子操作）
        Boolean isSet = redisTemplate.opsForValue().setIfAbsent(uniqueKey, "LOCK", expireTime, TimeUnit.MILLISECONDS);
        if (isSet == null || !isSet) {
            throw new RuntimeException("重复请求，请稍后再试");
        }

        try {
            return joinPoint.proceed();
        } finally {
            // 业务完成后可选延长过期时间或保留原设置
            // redisTemplate.expire(uniqueKey, 60, TimeUnit.SECONDS);
        }
    }

    private String generateUniqueKey(ProceedingJoinPoint joinPoint, String prefix) {
        // 从请求参数或Header中提取唯一ID（示例从参数获取）
        Object[] args = joinPoint.getArgs();
        String requestId = (String) Arrays.stream(args)
                .filter(arg -> arg instanceof String && ((String) arg).startsWith("req_"))
                .findFirst()
                .orElse(UUID.randomUUID().toString());
        return prefix + requestId;
    }
}

@RestController
public class OrderController {
    @PostMapping("/pay")
    @Idempotent(keyPrefix = "order:pay:", expireTime = 60000)
    public ResponseEntity<String> payOrder(@RequestParam String orderId, @RequestParam String reqId) {
        // 业务逻辑（如扣款、更新订单状态）
        return ResponseEntity.ok("支付成功");
    }
}