java CountDownLatch 模拟用户并发请求

来源：互联网发布：fs2you下载器 mac 编辑：程序博客网时间：2024/06/04 18:39

java.util.concurrent.CountDownLatch,一个同步辅助类，在完成一组正在其他线程中执行的操作之前，它允许一个或多个线程一直等待。

主要方法
public CountDownLatch(int count);
public void countDown();
public void await() throws InterruptedException

构造方法参数指定了计数的次数
countDown方法，当前线程调用此方法，则计数减一
awaint方法，调用此方法会一直阻塞当前线程，直到计时器的值为0

示例代码：模拟多用户请求

package com.settlement.concurrent;import java.text.SimpleDateFormat;import java.util.Date;import java.util.concurrent.CountDownLatch;import com.settlement.commons.utils.HttpRequest;/** * 模拟用户的并发请求，检测用户乐观锁的性能问题 *  * @author zzg * @date 2017-02-10 */public class ConcurrentTest {final static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); public static void main(String[] args){CountDownLatch latch=new CountDownLatch(1);//模拟5人并发请求，用户钱包for(int i=0;i<5;i++){//模拟5个用户AnalogUser analogUser = new AnalogUser("user"+i,"58899dcd-46b0-4b16-82df-bdfd0d953bfb","1","20.024",latch);analogUser.start();}latch.countDown();//计数器減一  所有线程释放 并发访问。System.out.println("所有模拟请求结束  at "+sdf.format(new Date()));  }static class AnalogUser extends Thread{String workerName;//模拟用户姓名String openId;String openType;String amount;CountDownLatch latch;public AnalogUser(String workerName, String openId, String openType, String amount,CountDownLatch latch) {super();this.workerName = workerName;this.openId = openId;this.openType = openType;this.amount = amount;this.latch = latch;}@Overridepublic void run() {// TODO Auto-generated method stubtry {  latch.await(); //一直阻塞当前线程，直到计时器的值为0          } catch (InterruptedException e) {              e.printStackTrace();          }  post();//发送post 请求                } public void post(){String result = "";System.out.println("模拟用户： "+workerName+" 开始发送模拟请求  at "+sdf.format(new Date()));  result = HttpRequest.sendPost("http://localhost:8080/Settlement/wallet/walleroptimisticlock.action", "openId="+openId+"&openType="+openType+"&amount="+amount);System.out.println("操作结果："+result);System.out.println("模拟用户： "+workerName+" 模拟请求结束  at "+sdf.format(new Date())); }}}

0 0