實例：接口並發限流RateLimiter

需求：接口每秒最多只能相應1個請求

 

1.創建 全局類對象

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

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

    /**
     * 獲取等待時間 方法阻塞
     * 每次等待一個獲取一個令牌
     * @return
     */
    public double acquire(){
        double waitTime = rateLimiter.acquire(1);
        return waitTime;
    }
}

2.測試實例  模擬10個並發請求

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

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

    @Autowired
    private NearestAirportService nearestAirportService;

    @Autowired
    private AccessLimitService accessLimitService;

    /**
　　 * 此方法是我們對外提供的接口，通過調用acquire()方法獲取令牌，獲取失時會阻塞直到獲取令牌成功才繼續執行
　　 */
    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);
　　　　//開啟10個線程模擬10個並發請求 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. 執行結果：getNearestAirpor()方法每秒只執行了一次

總結：關鍵是要讓  rateLimiter  變量成為線程共享變量，每個請求執行前都要來到 rateLimiter 中獲取令牌。成功擇執行，失敗則阻塞 直到拿到令牌才繼續執行