Spring中的并行请求数与http-nio-8080-exec线程数
我想在我的控制器中测试并行请求。我知道默认情况下Spring可以处理200个并行请求，我们可以通过修改这个属性server.tomcat.max-threads来改变它
我尝试了一下这个值，发现了一些有趣的事情:当我将它设置为3时，当我启动应用程序时，我看到3个线程正在被创建：http-nio-8080-exec-1,2,3当我将它设置为5时，我看到5个这样的线程。当我将其设置为15时，仍然有10个名为http-nio-8080-exec的线程。有人能解释一下为什么从来不超过10吗？
如果我要做这样的控制器
@GetMapping("test")
public String test(@RequestParam("skip") boolean skip) throws InterruptedException {
if(!skip) {
System.out.println("I'm starting waiting");
Thread.sleep(10000);
System.out.println("I stopped waiting");
}
return "dd";
}同时使用server.tomcat.max-threads=200
提出10个这样的请求：http://localhost:8080/test?skip=false
和第11个请求同时进行：http://localhost:8080/test?skip=true
前10个请求应该在返回响应之前等待10秒，但第11个请求应该立即返回-问题是第11个请求也在等待，所以它被阻塞了。有人能解释一下它是怎么工作的吗？如果我将server.tomcat.max-threads设置为200，那么我预计我将能够处理200个独立请求，对吗？
回答 1
Stack Overflow用户
发布于 2020-03-09 02:50:56
我对这种行为很好奇，并亲自测试了一下。不幸的是，我不能确认你的行为。为了能够同时测试对服务的请求，我编写了一个简单的go程序来证明响应时间。因此，我使用您在上面发布的代码启动了一个带有单个rest端点的spring启动服务，并以客户端的身份遵循go programm：
package main
import (
"log"
"os/exec"
"time"
)
func main() {
for i := 0; i< 15; i++ {
go runCmd(i)
}
time.Sleep(time.Second * 50)
}
func runCmd(i int) {
param := "localhost:8080/test?skip=false"
if i > 10 {
param = "localhost:8080/test?skip=true"
}
cmd := exec.Command("curl", param)
log.Printf("Running command %d and waiting for it to finish...", i)
start := time.Now()
err := cmd.Run()
end := time.Now()
duration := end.Sub(start)
log.Printf("Command %d finished within of second %f error: %v", i, duration.Seconds(), err)
}这个程序使用curl发送前10个带有参数skip=false的请求，以及另外5个带有skip=true的请求。输出结果是：
2020/03/08 19:21:18 Running command 14 and waiting for it to finish...
2020/03/08 19:21:18 Running command 9 and waiting for it to finish...
2020/03/08 19:21:18 Running command 3 and waiting for it to finish...
2020/03/08 19:21:18 Running command 10 and waiting for it to finish...
2020/03/08 19:21:18 Running command 7 and waiting for it to finish...
2020/03/08 19:21:18 Running command 0 and waiting for it to finish...
2020/03/08 19:21:18 Running command 12 and waiting for it to finish...
2020/03/08 19:21:18 Running command 6 and waiting for it to finish...
2020/03/08 19:21:18 Running command 5 and waiting for it to finish...
2020/03/08 19:21:18 Running command 13 and waiting for it to finish...
2020/03/08 19:21:18 Running command 11 and waiting for it to finish...
2020/03/08 19:21:18 Running command 2 and waiting for it to finish...
2020/03/08 19:21:18 Running command 1 and waiting for it to finish...
2020/03/08 19:21:18 Running command 4 and waiting for it to finish...
2020/03/08 19:21:18 Running command 8 and waiting for it to finish...
2020/03/08 19:21:18 Command 12 finished within of second 0.035109 error: <nil>
2020/03/08 19:21:18 Command 14 finished within of second 0.035290 error: <nil>
2020/03/08 19:21:18 Command 11 finished within of second 0.040090 error: <nil>
2020/03/08 19:21:18 Command 13 finished within of second 0.041358 error: <nil>
2020/03/08 19:21:28 Command 9 finished within of second 10.034510 error: <nil>
2020/03/08 19:21:28 Command 0 finished within of second 10.034436 error: <nil>
2020/03/08 19:21:28 Command 10 finished within of second 10.037470 error: <nil>
2020/03/08 19:21:28 Command 6 finished within of second 10.042294 error: <nil>
2020/03/08 19:21:28 Command 5 finished within of second 10.042328 error: <nil>
2020/03/08 19:21:28 Command 7 finished within of second 10.045510 error: <nil>
2020/03/08 19:21:28 Command 3 finished within of second 10.045638 error: <nil>
2020/03/08 19:21:28 Command 1 finished within of second 10.049024 error: <nil>
2020/03/08 19:21:28 Command 2 finished within of second 10.053824 error: <nil>
2020/03/08 19:21:28 Command 8 finished within of second 10.053102 error: <nil>
2020/03/08 19:21:28 Command 4 finished within of second 10.053306 error: <nil>正如您在输出中看到的，请求11 - 14在没有延迟的情况下完成，因此它们没有被阻塞。所以你可能不得不检查你的测试，可能问题出在测试中的某个地方，而不是tomcat配置中。
而且处理200个独立请求的期望是正确的，所以它应该这样做，它也应该这样做。
https://stackoverflow.com/questions/60587217
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