├── README.md ├── src └── com │ └── tianxiaobo │ └── ratelimiter │ ├── RateLimiter.java │ ├── RejectException.java │ ├── TimestampHolder.java │ ├── RateCounter.java │ ├── TokenBucketLimiter.java │ └── LeakyBucketLimiter.java ├── .gitignore └── LICENSE /README.md: -------------------------------------------------------------------------------- 1 | # RateLimiter 2 | 本项目是文章 [简析限流算法](http://www.tianxiaobo.com/2019/05/18/%E7%AE%80%E6%9E%90%E9%99%90%E6%B5%81%E7%AE%97%E6%B3%95/) 的示例代码，包含计数器、漏桶和令牌桶算法实现。代码实现较为简单，仅做演示使用。 3 | -------------------------------------------------------------------------------- /src/com/tianxiaobo/ratelimiter/RateLimiter.java: -------------------------------------------------------------------------------- 1 | package com.tianxiaobo.ratelimiter; 2 | 3 | /** 4 | * RateLimiter 5 | * 6 | * @author Tian ZhongBo 7 | * @date 2019-05-09 22:07:38 8 | */ 9 | public interface RateLimiter { 10 | 11 | void acquire(); 12 | } 13 | -------------------------------------------------------------------------------- /src/com/tianxiaobo/ratelimiter/RejectException.java: -------------------------------------------------------------------------------- 1 | package com.tianxiaobo.ratelimiter; 2 | 3 | /** 4 | * RejectException 5 | * 6 | * @author Tian ZhongBo 7 | * @date 2019-05-08 22:58:28 8 | */ 9 | public class RejectException extends RuntimeException { 10 | 11 | } 12 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled class file 2 | *.class 3 | 4 | # Log file 5 | *.log 6 | 7 | # BlueJ files 8 | *.ctxt 9 | 10 | # Mobile Tools for Java (J2ME) 11 | .mtj.tmp/ 12 | 13 | # Package Files # 14 | *.jar 15 | *.war 16 | *.nar 17 | *.ear 18 | *.zip 19 | *.tar.gz 20 | *.rar 21 | 22 | # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml 23 | hs_err_pid* 24 | 25 | *.iml 26 | .idea/* 27 | -------------------------------------------------------------------------------- /src/com/tianxiaobo/ratelimiter/TimestampHolder.java: -------------------------------------------------------------------------------- 1 | package com.tianxiaobo.ratelimiter; 2 | 3 | /** 4 | * TimestampHolder 5 | * 6 | * @author Tian ZhongBo 7 | * @date 2019-05-09 22:37:19 8 | */ 9 | public class TimestampHolder { 10 | private long timestamp; 11 | 12 | public TimestampHolder() { 13 | this(System.currentTimeMillis()); 14 | } 15 | 16 | public TimestampHolder(long timestamp) { 17 | this.timestamp = timestamp; 18 | } 19 | 20 | public long getTimestamp() { 21 | return timestamp; 22 | } 23 | 24 | public void setTimestamp(long timestamp) { 25 | this.timestamp = timestamp; 26 | } 27 | } 28 | -------------------------------------------------------------------------------- /src/com/tianxiaobo/ratelimiter/RateCounter.java: -------------------------------------------------------------------------------- 1 | package com.tianxiaobo.ratelimiter; 2 | 3 | import java.util.concurrent.ExecutorService; 4 | import java.util.concurrent.Executors; 5 | import java.util.concurrent.atomic.AtomicInteger; 6 | 7 | public class RateCounter implements RateLimiter { 8 | 9 | private static final int DEFAULT_RATE_LIMIT_PER_SECOND = Integer.MAX_VALUE; 10 | 11 | private int limit; 12 | 13 | private AtomicInteger counter; 14 | 15 | public RateCounter() { 16 | this(DEFAULT_RATE_LIMIT_PER_SECOND); 17 | } 18 | 19 | public RateCounter(int limit) { 20 | if (limit < 0) { 21 | throw new IllegalArgumentException("limit less than zero"); 22 | } 23 | this.limit = limit; 24 | counter = new AtomicInteger(); 25 | TimestampHolder holder = new TimestampHolder(); 26 | ExecutorService executorService = Executors.newSingleThreadExecutor(); 27 | executorService.submit(() -> { 28 | while (true) { 29 | long cur = System.currentTimeMillis(); 30 | if (cur - holder.getTimestamp() >= 1000) { 31 | holder.setTimestamp(cur); 32 | counter.set(0); 33 | } 34 | 35 | try { 36 | Thread.sleep(1); 37 | } catch (InterruptedException e) { 38 | e.printStackTrace(); 39 | } 40 | } 41 | }); 42 | } 43 | 44 | @Override 45 | public void acquire() { 46 | if (counter.incrementAndGet() > limit) { 47 | throw new RejectException(); 48 | } 49 | } 50 | 51 | public static void main(String[] args) { 52 | RateLimiter rateLimiter = new RateCounter(10); 53 | 54 | int num = 100; 55 | while (num > 0) { 56 | try { 57 | rateLimiter.acquire(); 58 | } catch (Exception e) { 59 | continue; 60 | } 61 | 62 | num--; 63 | System.out.println("sec: " + System.currentTimeMillis() / 1000L + ", mil: " + System.currentTimeMillis() + " got a token"); 64 | } 65 | } 66 | } 67 | -------------------------------------------------------------------------------- /src/com/tianxiaobo/ratelimiter/TokenBucketLimiter.java: -------------------------------------------------------------------------------- 1 | package com.tianxiaobo.ratelimiter; 2 | 3 | import java.util.Objects; 4 | import java.util.Queue; 5 | import java.util.concurrent.ExecutorService; 6 | import java.util.concurrent.Executors; 7 | import java.util.concurrent.LinkedBlockingQueue; 8 | import java.util.concurrent.TimeUnit; 9 | 10 | /** 11 | * TokenBucketLimiter 12 | * 13 | * @author Tian ZhongBo 14 | * @date 2019-05-13 10:12:11 15 | */ 16 | public class TokenBucketLimiter implements RateLimiter { 17 | 18 | private static final int DEFAULT_RATE_LIMIT_PER_SECOND = Integer.MAX_VALUE; 19 | 20 | private static final long NANOSECOND = 1000 * 1000 * 1000; 21 | 22 | private static final Object TOKEN = new Object(); 23 | 24 | private Queue tokenBucket; 25 | 26 | public TokenBucketLimiter() { 27 | this(DEFAULT_RATE_LIMIT_PER_SECOND); 28 | } 29 | 30 | public TokenBucketLimiter(int limit) { 31 | if (limit <= 0) { 32 | throw new IllegalArgumentException(); 33 | } 34 | 35 | tokenBucket = new LinkedBlockingQueue<>(limit); 36 | ExecutorService threadPool = Executors.newSingleThreadExecutor(); 37 | 38 | TimestampHolder holder = new TimestampHolder(System.nanoTime()); 39 | long interval = NANOSECOND / limit; 40 | threadPool.submit(() -> { 41 | while (true) { 42 | long cur = System.nanoTime(); 43 | if (cur - holder.getTimestamp() >= interval) { 44 | tokenBucket.offer(TOKEN); 45 | holder.setTimestamp(cur); 46 | } 47 | 48 | try { 49 | TimeUnit.NANOSECONDS.sleep(1000); 50 | } catch (InterruptedException e) { 51 | e.printStackTrace(); 52 | } 53 | } 54 | }); 55 | } 56 | 57 | @Override 58 | public void acquire() { 59 | Object token = tokenBucket.poll(); 60 | if (Objects.isNull(token)) { 61 | throw new RejectException(); 62 | } 63 | } 64 | 65 | public static void main(String[] args) throws InterruptedException { 66 | RateLimiter rateLimiter = new TokenBucketLimiter(10); 67 | 68 | Runnable runnable = () -> { 69 | int num = 100; 70 | while (num > 0) { 71 | try { 72 | rateLimiter.acquire(); 73 | } catch (Exception e) { 74 | continue; 75 | } 76 | 77 | num--; 78 | System.out.println("Thread: " + Thread.currentThread().getName() + ", sec: " + System.currentTimeMillis() / 1000L + ", mil: " + System.currentTimeMillis() + " got a token"); 79 | } 80 | }; 81 | 82 | ExecutorService threadPool = Executors.newCachedThreadPool(); 83 | for (int i = 0; i < 10; i++) { 84 | threadPool.submit(runnable); 85 | } 86 | threadPool.awaitTermination(100, TimeUnit.SECONDS); 87 | } 88 | } 89 | -------------------------------------------------------------------------------- /src/com/tianxiaobo/ratelimiter/LeakyBucketLimiter.java: -------------------------------------------------------------------------------- 1 | package com.tianxiaobo.ratelimiter; 2 | 3 | import java.util.Optional; 4 | import java.util.concurrent.BlockingQueue; 5 | import java.util.concurrent.ExecutorService; 6 | import java.util.concurrent.Executors; 7 | import java.util.concurrent.LinkedBlockingQueue; 8 | import java.util.concurrent.TimeUnit; 9 | import java.util.concurrent.locks.LockSupport; 10 | 11 | /** 12 | * LeakyBucketLimiter 13 | * 14 | * @author Tian ZhongBo 15 | * @date 2019-05-09 22:07:05 16 | */ 17 | public class LeakyBucketLimiter implements RateLimiter { 18 | 19 | private static final int DEFAULT_RATE_LIMIT_PER_SECOND = Integer.MAX_VALUE; 20 | 21 | private static final long NANOSECOND = 1000 * 1000 * 1000; 22 | 23 | private BlockingQueue bucket; 24 | 25 | public LeakyBucketLimiter() { 26 | this(DEFAULT_RATE_LIMIT_PER_SECOND); 27 | } 28 | 29 | public LeakyBucketLimiter(int limit) { 30 | if (limit <= 0) { 31 | throw new IllegalArgumentException(); 32 | } 33 | 34 | bucket = new LinkedBlockingQueue<>(limit); 35 | ExecutorService threadPool = Executors.newSingleThreadExecutor(); 36 | 37 | TimestampHolder holder = new TimestampHolder(System.nanoTime()); 38 | long interval = NANOSECOND / limit; 39 | threadPool.submit(() -> { 40 | while (true) { 41 | long cur = System.nanoTime(); 42 | if (cur - holder.getTimestamp() >= interval) { 43 | Thread thread = bucket.poll(); 44 | Optional.ofNullable(thread).ifPresent(LockSupport::unpark); 45 | holder.setTimestamp(cur); 46 | } 47 | 48 | try { 49 | TimeUnit.NANOSECONDS.sleep(1000); 50 | } catch (InterruptedException e) { 51 | e.printStackTrace(); 52 | } 53 | } 54 | }); 55 | } 56 | 57 | @Override 58 | public void acquire() { 59 | if (bucket.remainingCapacity() == 0) { 60 | throw new RejectException(); 61 | } 62 | 63 | Thread thread = Thread.currentThread(); 64 | bucket.add(thread); 65 | LockSupport.park(); 66 | } 67 | 68 | public static void main(String[] args) throws InterruptedException { 69 | RateLimiter rateLimiter = new LeakyBucketLimiter(1); 70 | 71 | Runnable runnable = () -> { 72 | int num = 100; 73 | while (num > 0) { 74 | try { 75 | rateLimiter.acquire(); 76 | } catch (Exception e) { 77 | continue; 78 | } 79 | 80 | num--; 81 | System.out.println("Thread: " + Thread.currentThread().getName() + ", sec: " + System.currentTimeMillis() / 1000L + ", mil: " + System.currentTimeMillis() + " got a token"); 82 | } 83 | }; 84 | 85 | long start = System.currentTimeMillis(); 86 | ExecutorService threadPool = Executors.newCachedThreadPool(); 87 | for (int i = 0; i < 10; i++) { 88 | threadPool.submit(runnable); 89 | } 90 | threadPool.awaitTermination(100, TimeUnit.SECONDS); 91 | long end = System.currentTimeMillis(); 92 | System.out.println("over time: " + (end - start) / 1000); 93 | } 94 | } 95 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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