springboot 虚拟线程demo

jd19支持虚拟线程，虚拟线程是轻量级的线程，它们不与操作系统线程绑定，而是由 JVM 来管理。它们适用于“每个请求一个线程”的编程风格，同时没有操作系统线程的限制。我们能够创建数以百万计的虚拟线程而不会影响吞吐。

做个 springboot demo 尝试一下。

环境

• jdk19
• gradle 7.6.1
• IntelliJ IDEA 2022.2.4

build.gradle

plugins {id 'java'id 'org.springframework.boot' version '3.0.3'id 'io.spring.dependency-management' version '1.1.0'
}group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '19'configurations {compileOnly {extendsFrom annotationProcessor}
}repositories {mavenCentral()
}dependencies {implementation 'org.springframework.boot:spring-boot-starter'compileOnly 'org.projectlombok:lombok'developmentOnly 'org.springframework.boot:spring-boot-devtools'annotationProcessor 'org.projectlombok:lombok'testImplementation 'org.springframework.boot:spring-boot-starter-test'
}tasks.named('test') {useJUnitPlatform()
}tasks.withType(JavaCompile) {options.compilerArgs += "--enable-preview"
}

多线程demo

写一段多线程调用的代码，程序入口

package com.example.myvirtualthreaddemo;import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.core.task.AsyncTaskExecutor;
import org.springframework.core.task.support.TaskExecutorAdapter;
import org.springframework.scheduling.annotation.EnableAsync;import java.util.concurrent.Executors;@EnableAsync
@SpringBootApplication
public class MyVirtualThreadDemoApplication {public static void main(String[] args) {SpringApplication.run(MyVirtualThreadDemoApplication.class, args);}@BeanCommandLineRunner commandLineRunner(AsyncService asyncService){return args -> {for(int i = 0; i < 100; i++){asyncService.fun(i);}};}
}

package com.example.myvirtualthreaddemo;import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;@Service
@Slf4j
public class AsyncService {@Asyncpublic void fun(int i) {log.info("fun:{}", i);}
}

运行结果，使用平台线程（默认8个）

使用虚拟线程

在MyVirtualThreadDemoApplication添加以下代码块

@Bean(TaskExecutionAutoConfiguration.APPLICATION_TASK_EXECUTOR_BEAN_NAME)public AsyncTaskExecutor asyncTaskExecutor(){return new TaskExecutorAdapter(Executors.newVirtualThreadPerTaskExecutor());}

运行结果，使用虚拟线程

遇到的一些问题

请使用 --enable-preview 以启用预览 API

解决办法：

1. build.gradle里添加以下配置：

tasks.withType(JavaCompile) {options.compilerArgs += "--enable-preview"
}

2. 设置vm选项如图