本文主要向大家介绍了Java语言代码模拟并发请求对接口进行压测（代码实例），通过具体的内容向大家展示，希望对大家学习JAVA语言有所帮助。

案例：编写一段代码，模拟并发请求为20，且总的请求数为1000，当1000个请求完成之后，打印“请求完成”。

实现代码：

/**

 * 目标：编写一段代码，模拟并发请求为20，且总的请求数为1000，当1000个请求完成后，打印“请求完成”

 */

@Slf4j

public class TestConcurrentRequest {

    // 总的请求个数

    public static final int requestTotal = 1000;

    // 同一时刻最大的并发线程的个数

    public static final int concurrentThreadNum = 20;

    public static void main(String[] args) throws InterruptedException {

        ExecutorService executorService = Executors.newCachedThreadPool();

        CountDownLatch countDownLatch = new CountDownLatch(requestTotal);

        Semaphore semaphore = new Semaphore(concurrentThreadNum);

        for (int i = 0; i< requestTotal; i++) {

            executorService.execute(()->{

                try {

                    semaphore.acquire();

                    String result = testRequestUri();

                    log.info("result:{}.", result);

                    semaphore.release();

                } catch (InterruptedException e) {

                    log.error("exception", e);

                }

                countDownLatch.countDown();

            });

        }

        countDownLatch.await();

        executorService.shutdown();

        log.info("请求完成");

    }

    private static String testRequestUri() {

        return HttpClientUtil.get("https://localhost:8080/test");

    }

}

注意：上述代码中，countDownLatch.countDown();需要放在每个线程中进行countDownLatch.countDown(),而不能通过主线程来执行countDownLatch.countDown();

输出打印日志为：

Connected to the target VM, address: '127.0.0.1:62593', transport: 'socket'

[pool-1-thread-12] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-4] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-9] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

...

[pool-1-thread-944] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-997] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-976] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-926] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-999] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[main] INFO com.example.concurrent.TestConcurrentRequest - 请求完成

可以看到，当大概1000个请求发送完成之后，才打印“请求完成”。

由于我们使用的是： ExecutorService executorService = Executors.newCachedThreadPool();因此，会不断的创建新的线程。如果改为：ExecutorService executorService = Executors.newFixedThreadPool(concurrentThreadNum);

则输出日志为：

[pool-1-thread-18] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-8] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-4] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-6] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

...

[pool-1-thread-1] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-7] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-14] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-16] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-12] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[pool-1-thread-3] INFO com.example.concurrent.TestConcurrentRequest - result:test2.

[main] INFO com.example.concurrent.TestConcurrentRequest - 请求完成

可以看到，线程[pool-1-thread-3]被复用了。

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