实例：接口并发限流RateLimiter

需求：接口每秒最多只能相应1个请求

 

1.创建 全局类对象

import com.google.common.util.concurrent.RateLimiter;
import org.springframework.stereotype.Service;

/**
 * @Auther: 011336
 * @Date: 2019/4/29 17:31
 */
@Service
public class AccessLimitService {
    /**
     * 每秒只发出1个令牌
     */
    RateLimiter rateLimiter = RateLimiter.create(1.0);

    /**
     * 获取等待时间 方法阻塞
     * 每次等待一个获取一个令牌
     * @return
     */
    public double acquire(){
        double waitTime = rateLimiter.acquire(1);
        return waitTime;
    }
}

2.测试实例  模拟10个并发请求

@Controller
@RequestMapping("/SegmentRecommend")
public class NearestAirportController {

    private Logger logger = Logger.getLogger(NearestAirportController.class);

    @Autowired
    private NearestAirportService nearestAirportService;

    @Autowired
    private AccessLimitService accessLimitService;

    /**
　　  * 此方法是我们对外提供的接口，通过调用acquire()方法获取令牌，获取失时会阻塞直到获取令牌成功才继续执行
　　  */
    public ModelAndView getNearestAirport(HttpServletRequest request, HttpServletResponse response)throws Exception {
        logger.info("NearestAirportController.getNearestAirport begin");
        System.out.println(" |||||||||||||waitTime:" + accessLimitService.acquire());
        RemoteAirportsData data = nearestAirportService.getNearestAirports();
        logger.info("NearestAirportController.getNearestAirport end");
        return null;
    }
    @RequestMapping(value ="/GetNearestAirport" ,produces = "application/json;charset=UTF-8")
    public ModelAndView ttttt (HttpServletRequest request, HttpServletResponse response) throws Exception{
        logger.info("=============================================================================");
        ExecutorService fixedThreadPool = Executors.newFixedThreadPool(10);
　　　　//开启10个线程模拟10个并发请求  
        for(int i=0;i<10;i++) {
            fixedThreadPool.submit(new Runnable() {
                @Override
                public void run() {
                    try {
                        getNearestAirport(request,response);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        }
        fixedThreadPool.shutdown();
        fixedThreadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);
        logger.info("================================================================================");
        return null;
    }
}

3. 执行结果：getNearestAirpor()方法每秒只执行了一次

总结：关键是要让  rateLimiter  变量成为线程共享变量，每个请求执行前都要来到 rateLimiter 中获取令牌。成功择执行，失败则阻塞 直到拿到令牌才继续执行