英文:
Spring boot web app acts like it's single-threaded
问题
以下是翻译好的部分：
我正在本地测试一个 Spring Boot 控制器，我注意到了一些令我感到惊讶的行为。我编写了这个示例控制器方法：
@GetMapping()
public void test() throws InterruptedException {
for(int i = 0; i < 5 ; i++) {
Thread.sleep(1000);
System.out.println(Thread.currentThread().getName() + " " + i);
}
}
然后我从两个不同的标签页几乎同时调用了这个端点。我原以为会从两个线程中看到日志输出重叠（因为我认为每个请求都会创建一个新的执行线程）。然而，我得到的输出是：
http-nio-8080-exec-1 0
http-nio-8080-exec-1 1
http-nio-8080-exec-1 2
http-nio-8080-exec-1 3
http-nio-8080-exec-1 4
http-nio-8080-exec-1 0
http-nio-8080-exec-1 1
http-nio-8080-exec-1 2
http-nio-8080-exec-1 3
http-nio-8080-exec-1 4
这看起来像只有一个线程，第二个请求实际上等待第一个请求完成。我原以为 Tomcat 默认的最大线程值是 200。有人可以解释一下这个行为吗？为什么没有创建多个线程？
这是一个空白项目，是使用 Spring Initializer 创建的，只有 Spring Boot Starter Web 作为依赖。
英文:
I'm testing a Spring Boot controller locally and I noticed some behaviour that surprised me. I wrote this examplary controller method :
@GetMapping()
public void test() throws InterruptedException {
for(int i = 0; i < 5 ; i++) {
Thread.sleep(1000);
System.out.println(Thread.currentThread().getName() + " " + i);
}
}
And I called the endpoint twice from separate tabs almost at the same time. I was expecting to see log output overlapping from two threads (as I thought that each request would create a new execution thread). Meanwhile, the output I got was:
http-nio-8080-exec-1 0
http-nio-8080-exec-1 1
http-nio-8080-exec-1 2
http-nio-8080-exec-1 3
http-nio-8080-exec-1 4
http-nio-8080-exec-1 0
http-nio-8080-exec-1 1
http-nio-8080-exec-1 2
http-nio-8080-exec-1 3
http-nio-8080-exec-1 4
This looks like there's only one thread, and the second requested actually waited for the first one to finish. I thought the tomcat default max thread value was 200. Can someone please explain this behaviour to me? Why weren't there multiple threads created?
It's a blank project, created from Spring Initializer with only Spring Boot Starter Web as a dependency
答案1
得分: 1
在Spring中，每个请求都在单独的线程中执行。例如，当两个用户同时想要登录时，JVM会创建两个线程：一个线程用于第一个用户，另一个线程用于第二个用户。
我尝试了您的情况，它完美地运行了，可能是因为您的请求不是那么并发，您可以使用 curl 命令：
curl http://localhost:8080/hello/Logan & curl http://localhost:8080/hello/Leon
英文:
> In Spring every request is executed in separate thread. For
> example,when 2 users want to login at the same time, JVM creates 2
> threads: one thread for first user, another one for second user.
I tried your case and it works perfectly may be your requests are not that concurrent ,you can use curl
curl http://localhost:8080/hello/Logan & curl http://localhost:8080/hello/Leon
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论