&nbsp;외부 API 연동시 too many request 429 오류가 날 때 사용했던 코드&nbsp;&nbsp;<div style="background-color:#282c34;color:#abb2bf;"><pre style="font-family:'JetBrains Mono',monospace;font-size:9.4pt;">package com.example.demo; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.TimeUnit; import org.apache.commons.lang3.concurrent.TimedSemaphore; import org.springframework.stereotype.Component; @Component public class TimedSemaphoreHandler { private final ConcurrentHashMap&lt;String, TimedSemaphore&gt; semaphoreMap = new ConcurrentHashMap&lt;&gt;(); // milliseconds private final long DEFAULT_TIME_PERIOD = 500; // numberOfOperationsToOperateSimultaneously private final int DEFAULT_LIMIT = 1; public TimedSemaphore getSemaphore(String key, int timePeriod, int limit) { return semaphoreMap.computeIfAbsent(key, k -&gt; new TimedSemaphore(timePeriod, TimeUnit.MILLISECONDS, limit)); } public TimedSemaphore getSemaphore(String key, int timePeriod) { return semaphoreMap.computeIfAbsent(key, k -&gt; new TimedSemaphore(timePeriod, TimeUnit.MILLISECONDS, DEFAULT_LIMIT)); } public TimedSemaphore getSemaphore(String key) { return semaphoreMap.computeIfAbsent(key, k -&gt; new TimedSemaphore(DEFAULT_TIME_PERIOD, TimeUnit.MILLISECONDS, DEFAULT_LIMIT)); } } &nbsp;</pre></div>&nbsp;&nbsp;<div style="background-color:#282c34;color:#abb2bf;"><pre style="font-family:'JetBrains Mono',monospace;font-size:9.4pt;">@Slf4j @Service @RequiredArgsConstructor public class WhyService { private final TimedSemaphoreHandler timedSemaphoreHandler; //호출 @Async public void testShmaphore() { for (int i = 0; i &lt; 10; i++) { try { // semaphore를 가져와서 획득할 때 까지 대기 timedSemaphoreHandler.getSemaphore("testKey", 5000, 2).acquire(); } catch (InterruptedException e) { log.error(e.getMessage()); } // 하고 싶은 일 log.warn("msg {}", i); } } }</pre></div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

[Java] Too Many Request 429 오류시에 천천히 동작하도록 하는 방법 TimedSemaphore