【高并发】02 并发工具测试类

1、Postman:模拟Http请求

2、Apache Bench(AB): Apache 附带的工具,测试网站性能

# ab -n 1000 -c 50 http://localhost:8080/hello

-n: 并发总数

-c: 允许一次请求并发数

3、JMeter: Apche 组织开发的压力测试工具

4、代码测试: 结合Semaphore、CountDownLatch

package com.current.flame.test;

import com.current.flame.annoations.NotThreadSafe;
import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

/**
 * @author haoxiansheng
 */
@Slf4j
@NotThreadSafe
public class ConcurrencyTest {
    // 请求总数
    public static int clientTotal = 5000;

    // 允许同时执行的线程并发数
    public static int threadTotal = 200;

    public static int count = 0;

    public static void main(String[] args) throws InterruptedException {
        ExecutorService executorService = Executors.newCachedThreadPool();

        final Semaphore semaphore = new Semaphore(threadTotal); // 信号量 允许有多少个同时执行
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal); // 闭锁
        for (int i = 0; i < clientTotal; i++) {
            executorService.execute(() -> {
                try {
                    semaphore.acquire();
                    add();
                    semaphore.release();
                } catch (Exception e) {
                    log.info("e=>{}", e.getMessage());
                }
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        log.info("count==>{}", count);
        executorService.shutdown();
    }

    /**
     * 这是不安全的 加synchronized
     */
    private static void add() {
        count++;
    }
}