1、需要引入Redis的maven坐标
<!--redis和 springboot集成的包 -->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId><version>2.3.0.RELEASE</version>
</dependency>
2、redis配置
spring:# Redis数据库索引redis:database: 0# Redis服务器地址host: 127.0.0.1# Redis服务器连接端口port: 6379# Redis服务器连接密码（默认为空）password:# 连接池最大连接数（使用负值表示没有限制）jedis:pool:max-active: 8# 连接池最大阻塞等待时间（使用负值表示没有限制）max-wait: -1# 连接池中的最大空闲连接max-idle: 8# 连接池中的最小空闲连接min-idle: 0# 连接超时时间（毫秒）timeout: 10000
3、新建脚本放在该项目的 resources 目录下，新建 limit.lua
local key = KEYS[1] --限流KEY
local limit = tonumber(ARGV[1]) --限流大小
local current = tonumber(redis.call('get', key) or "0") if current + 1 > limit then
return 0 else redis.call("INCRBY", key,"1") redis.call("expire", key,"2") return current + 1 end
4、自定义限流注解
import java.lang.annotation.*;@Target(value = ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RedisRateLimiter {//往令牌桶放入令牌的速率double value() default Double.MAX_VALUE;//获取令牌的超时时间double limit() default Double.MAX_VALUE;
}
5、自定义切面类 RedisLimiterAspect 类 ，修改扫描自己controller类
import com.imooc.annotation.RedisRateLimiter;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.assertj.core.util.Lists;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.scripting.support.ResourceScriptSource;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.util.List;@Aspect
@Component
public class RedisLimiterAspect {@Autowiredprivate HttpServletResponse response;/*** 注入redis操作类*/@Autowiredprivate StringRedisTemplate stringRedisTemplate;private DefaultRedisScript<List> redisScript;/*** 初始化 redisScript 类* 返回值为 List*/@PostConstructpublic void init(){redisScript = new DefaultRedisScript<List>();redisScript.setResultType(List.class);redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("limit.lua")));}public final static Logger log = LoggerFactory.getLogger(RedisLimiterAspect.class);@Pointcut("execution( public * com.zz.controller.*.*(..))")public void pointcut(){}@Around("pointcut()")public Object process(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {MethodSignature signature = (MethodSignature)proceedingJoinPoint.getSignature();//使用Java 反射技术获取方法上是否有@RedisRateLimiter 注解类RedisRateLimiter redisRateLimiter = signature.getMethod().getDeclaredAnnotation(RedisRateLimiter.class);if(redisRateLimiter == null){//正常执行方法,执行正常业务逻辑return proceedingJoinPoint.proceed();}//获取注解上的参数，获取配置的速率double value = redisRateLimiter.value();double time = redisRateLimiter.limit();//list设置lua的keys[1]//取当前时间戳到单位秒String key = "ip:"+ System.currentTimeMillis() / 1000;List<String> keyList = Lists.newArrayList(key);//用户Mpa设置Lua 的ARGV[1]//List<String> argList = Lists.newArrayList(String.valueOf(value));//调用脚本并执行List result = stringRedisTemplate.execute(redisScript, keyList, String.valueOf(value),String.valueOf(time));log.info("限流时间段内访问第：{} 次", result.toString());//lua 脚本返回 "0" 表示超出流量大小，返回1表示没有超出流量大小if(StringUtils.equals(result.get(0).toString(),"0")){//服务降级fullback();return null;}// 没有限流，直接放行return proceedingJoinPoint.proceed();}/*** 服务降级方法*/private void fullback(){response.setCharacterEncoding("UTF-8");response.setContentType("application/json; charset=utf-8");PrintWriter writer = null;try {writer= response.getWriter();JSONObject o = new JSONObject();o.put("status",500);o.put("msg","Redis限流：请求太频繁，请稍后重试！");o.put("data",null);writer.printf(o.toString());}catch (Exception e){e.printStackTrace();}finally {if(writer != null){writer.close();}}}
}
6、在需要限流的类添加注解
import com.imooc.annotation.RedisRateLimiter;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.concurrent.TimeUnit;@RestController
@Api(value = "限流", tags = {"限流测试接口"})
@RequestMapping("limiter")
public class LimiterController {@ApiOperation(value = "Redis限流注解测试接口",notes = "Redis限流注解测试接口", httpMethod = "GET")@RedisRateLimiter(value = 10, limit = 1)@GetMapping("/redislimit")public IMOOCJSONResult redislimit(){System.out.println("Redis限流注解测试接口");return IMOOCJSONResult.ok();}}
)
