SpringBoot Redis用注释实现接口限流详解【java入门】

目录

• 1. 准备工作
• 2. 限流注解
• 3. 定制 RedisTemplate
• 4. 开发 Lua 脚本
• 5. 注解解析
• 6. 接口测试
• 7. 全局异常处理

    org.springframework.boot
    spring-boot-starter-data-redis


    org.springframework.boot
    spring-boot-starter-web


    org.springframework.boot
    spring-boot-starter-aop

public enum LimitType {
    /**
     * 默认策略全局限流
     */
    DEFAULT,
    /**
     * 根据请求者IP进行限流
     */
    IP
}

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RateLimiter {
    /**
     * 限流key
     */
    String key() default "rate_limit:";
    /**
     * 限流时间,单位秒
     */
    int time() default 60;
    /**
     * 限流次数
     */
    int count() default 100;
    /**
     * 限流类型
     */
    LimitType limitType() default LimitType.DEFAULT;
}

@Configuration
public class RedisConfig {
    @Bean
    public RedisTemplate redisTemplate(RedisConnectionFactory connectionFactory) {
        RedisTemplate redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(connectionFactory);
        // 使用Jackson2JsonRedisSerialize 替换默认序列化(默认采用的是JDK序列化)
        Jackson2JsonRedisSerializer jackson2JsOnRedisSerializer= new Jackson2JsonRedisSerializer<>(Object.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        redisTemplate.setKeySerializer(jackson2JsonRedisSerializer);
        redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
        redisTemplate.setHashKeySerializer(jackson2JsonRedisSerializer);
        redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);
        return redisTemplate;
    }
}

@Bean
public DefaultRedisScript limitScript() {
    DefaultRedisScript redisScript = new DefaultRedisScript<>();
    redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("lua/limit.lua")));
    redisScript.setResultType(Long.class);
    return redisScript;
}

@Aspect
@Component
public class RateLimiterAspect {
    private static final Logger log = LoggerFactory.getLogger(RateLimiterAspect.class);
    @Autowired
    private RedisTemplate redisTemplate;
    @Autowired
    private RedisScript limitScript;
    @Before("@annotation(rateLimiter)")
    public void doBefore(JoinPoint point, RateLimiter rateLimiter) throws Throwable {
        String key = rateLimiter.key();
        int time = rateLimiter.time();
        int count = rateLimiter.count();
        String combineKey = getCombineKey(rateLimiter, point);
        List keys = Collections.singletonList(combineKey);
        try {
            Long number = redisTemplate.execute(limitScript, keys, count, time);
            if (number==null || number.intValue() > count) {
                throw new ServiceException("访问过于频繁，请稍候再试");
            }
            log.info("限制请求"{}",当前请求"{}",缓存key"{}"", count, number.intValue(), key);
        } catch (ServiceException e) {
            throw e;
        } catch (Exception e) {
            throw new RuntimeException("服务器限流异常，请稍候再试");
        }
    }
    public String getCombineKey(RateLimiter rateLimiter, JoinPoint point) {
        StringBuffer stringBuffer = new StringBuffer(rateLimiter.key());
        if (rateLimiter.limitType() == LimitType.IP) {
            stringBuffer.append(IpUtils.getIpAddr(((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest())).append("-");
        }
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        Class targetClass = method.getDeclaringClass();
        stringBuffer.append(targetClass.getName()).append("-").append(method.getName());
        return stringBuffer.toString();
    }
}

@RestController
public class HelloController {
    @GetMapping("/hello")
    @RateLimiter(time = 5,count = 3,limitType = LimitType.IP)
    public String hello() {
        return "hello>>>"+new Date();
    }
}

@RestControllerAdvice
public class GlobalException {
    @ExceptionHandler(ServiceException.class)
    public Map serviceException(ServiceException e) {
        HashMap map = new HashMap<>();
        map.put("status", 500);
        map.put("message", e.getMessage());
        return map;
    }
}