RateLimit

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RateLimiter limiter = RateLimiter.create(4.0); //每秒不超过4个任务被提交limiter.acquire();  //请求RateLimiter, 超过permits会被阻塞executor.submit(runnable); //提交任务

If(limiter.tryAcquire()){ //未请求到limiter则立即返回false    doSomething();}else{    doSomethingElse();}

<dependency>            <groupId>com.google.guava</groupId>            <artifactId>guava</artifactId>            <version>14.0.1</version>        </dependency>

import java.util.concurrent.Callable;import java.util.concurrent.ExecutionException;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit; import com.google.common.util.concurrent.FutureCallback;import com.google.common.util.concurrent.Futures;import com.google.common.util.concurrent.ListenableFuture;import com.google.common.util.concurrent.ListeningExecutorService;import com.google.common.util.concurrent.MoreExecutors;import com.google.common.util.concurrent.RateLimiter; public class ListenableFutureDemo {    public static void main(String[] args) {        testRateLimiter();        testListenableFuture();    }     /**     * RateLimiter类似于JDK的信号量Semphore，他用来限制对资源并发访问的线程数     */    public static void testRateLimiter() {        ListeningExecutorService executorService = MoreExecutors                .listeningDecorator(Executors.newCachedThreadPool());         RateLimiter limiter = RateLimiter.create(5.0); // 每秒不超过4个任务被提交         for (int i = 0; i < 10; i++) {            limiter.acquire(); // 请求RateLimiter, 超过permits会被阻塞             final ListenableFuture<Integer> listenableFuture = executorService                    .submit(new Task("is "+ i));        }    }     public static void testListenableFuture() {        ListeningExecutorService executorService = MoreExecutors                .listeningDecorator(Executors.newCachedThreadPool());         final ListenableFuture<Integer> listenableFuture = executorService                .submit(new Task("testListenableFuture"));                  //同步获取调用结果        try {            System.out.println(listenableFuture.get());        } catch (InterruptedException e1) {            e1.printStackTrace();        } catch (ExecutionException e1) {            e1.printStackTrace();        }                 //第一种方式        listenableFuture.addListener(new Runnable() {            @Override            public void run() {                try {                    System.out.println("get listenable future's result "                            + listenableFuture.get());                } catch (InterruptedException e) {                    e.printStackTrace();                } catch (ExecutionException e) {                    e.printStackTrace();                }            }        }, executorService);         //第二种方式        Futures.addCallback(listenableFuture, new FutureCallback<Integer>() {            @Override            public void onSuccess(Integer result) {                System.out                        .println("get listenable future's result with callback "                                + result);            }             @Override            public void onFailure(Throwable t) {                t.printStackTrace();            }        });    }} class Task implements Callable<Integer> {    String str;    public Task(String str){        this.str = str;    }    @Override    public Integer call() throws Exception {        System.out.println("call execute.." + str);        TimeUnit.SECONDS.sleep(1);        return 7;    }}

package ratelimite;    import com.google.common.util.concurrent.RateLimiter;     public class RateLimiterDemo {      public static void main(String[] args) {          testNoRateLimiter();          testWithRateLimiter();      }         public static void testNoRateLimiter() {          Long start = System.currentTimeMillis();          for (int i = 0; i < 10; i++) {              System.out.println("call execute.." + i);                        }          Long end = System.currentTimeMillis();                    System.out.println(end - start);                }            public static void testWithRateLimiter() {          Long start = System.currentTimeMillis();          RateLimiter limiter = RateLimiter.create(10.0); // 每秒不超过10个任务被提交          for (int i = 0; i < 10; i++) {              limiter.acquire(); // 请求RateLimiter, 超过permits会被阻塞              System.out.println("call execute.." + i);                        }          Long end = System.currentTimeMillis();                    System.out.println(end - start);                }        }

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