接口调用频率限制代码
有很多时候我们写的代码不是你想跑多快就能跑多快的， 因为一些陈旧的核心系统支撑不了，在此万般无奈的情况下，
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调用老系统的接口，服务 就需要运维给一个可以接受的范围参考， 情景大概是这样，现实还是很难接受，明明写好的代码
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还用了一些自己优化技术来使代码运行的更快， 现实都是残酷的，不那么完美的， 与其被弓虽女干，不如好好享受一番。
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分享一下基于ThreadLocal限制调用频率的代码：
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其中引入了commons-lang里的StopWatch计时器
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/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.opencfg.core.limit;import org.apache.commons.lang.time.StopWatch;/** * <p> * Frequence Utils * <p> * * <p>#ThreadSafe#</p> * * @author Opencfg Software Foundation * @since 0.0.1-SNAPSHOT * @version $Id: FrequenceUtils.java 2011-06-11 23:58:53 reymondtu $ */public final class FrequenceUtils {/** * <p> * Limit call count in split time * </p> * * @param limitSplitTime * @param limitCount * @throws InterruptedException */public static void limit(final long limitSplitTime, final int limitCount) throws InterruptedException {FrequenceUnit funit = threadLocal.get();funit.limitSplitTime = limitSplitTime;funit.limitCount = limitCount;funit.watch.split();long diffTime = funit.limitSplitTime - funit.watch.getSplitTime();if (diffTime >= 0) {if (funit.realCount >= funit.limitCount) {funit.watch.suspend();Thread.sleep(diffTime);funit.watch.resume();funit.realCount = 0;}}funit.realCount++;}/** * FrequenceUnit */private static class FrequenceUnit {FrequenceUnit() {this.watch = new StopWatch();}long limitSplitTime;int limitCount;StopWatch watch;int realCount = 0;}private static ThreadLocal<FrequenceUnit> threadLocal = new ThreadLocal<FrequenceUnit>(){ protected synchronized FrequenceUnit initialValue() { FrequenceUnit funit = new FrequenceUnit(); funit.watch.start(); return funit; } };}?
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下边是测试用例：
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/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.opencfg.core.limit;import static org.junit.Assert.assertTrue;import org.junit.Test;/** * <p> * Frequence Utils Test * <p> * * <p>JUnit4 Test</p> * * @author Opencfg Software Foundation * @since 0.0.1-SNAPSHOT * @version $Id: FrequenceUtilsTest.java 2011-06-12 01:36:53 reymondtu $ */public class FrequenceUtilsTest {@Testpublic void testLimit() throws InterruptedException {FrequenceTestClass ftc = new FrequenceTestClass(1000, 10);for(int i = 0; i < 100; i++) {ftc.method(i);}assertTrue(true);}@Testpublic void testLimitMutiThreads() throws InterruptedException {Thread t1 = new Thread(new FrequenceTestClass(1000, 10));t1.start();Thread t2 = new Thread(new FrequenceTestClass(1000, 20));t2.start();Thread.sleep(10000);}class FrequenceTestClass implements Runnable {final long limitTime;final int limitCount;FrequenceTestClass(final long limitTime, final int limitCount) {this.limitTime = limitTime;this.limitCount = limitCount;}public void method(int i) throws InterruptedException {FrequenceUtils.limit(limitTime, limitCount);System.out.println("tid:" + Thread.currentThread().getId() + ", i=" + i);}@Overridepublic void run() {for(int i = 0; i < 100; i++) {try {method(i);} catch (InterruptedException e) {e.printStackTrace();}}}}}