起动机腹板如何防止Spring靴退出？

提问者：小点点

起动机腹板如何防止Spring靴退出？

当使用spring-boot-starter-web时，spring-boot应用程序在启动后不会退出。

使用Jetbrain IDEA，有一个图标显示Spring启动完成：

但如果我使用：

public static void main ( String[] args ){
    SpringApplication.run(Application.class, args);
    Thread.sleep(Long.MAX_VALUE);
}

或

public class MyRunner implements ApplicationRunner{
    public void run() {
        Thread.sleep(Long.MAX_VALUE);
    }
}

可以让spring-boot继续运行，但IDEA图标将永远加载，所以与入门网站相比，这一定是不同的方式。

更新1：这两种方法将导致SpringBootTest永远等待

问题:spring-boot-starter-web阻止spring-boot退出的代码是什么？

共2个答案

匿名用户

我不知道是什么原因，但如果没有Web服务器，只有当任何其他线程（非守护进程线程）仍处于活动状态时，才能防止关闭。另一个线程中的无限循环将阻止程序退出。

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        System.out.println("main started");
        new Thread(() -> {
            System.out.println("thread started");
            ConfigurableApplicationContext context = SpringApplication.run(DemoApplication.class, args);
            while (true) {
                System.out.println(context);
                try {
                    Thread.sleep(1000L);
                } catch (InterruptedException e) {
                }
            }
        }).start();
        System.out.println("main finished");
    }



}

输出示例

    main started
    main finished
    thread started

    .   ____          _            __ _ _
    /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
    ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
    \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
    '  |____| .__|_| |_|_| |_\__, | / / / /
    =========|_|==============|___/=/_/_/_/
    :: Spring Boot ::                (v2.6.7)

    2022-06-24 22:34:31.648  INFO 8084 --- [       Thread-1] o.s.boot.SpringApplication               : Starting application using Java 1.8.0_312 on DESKTOP with PID 8084 (started by user in C:\Users\user\IdeaProjects\demo)
    2022-06-24 22:34:31.650  INFO 8084 --- [       Thread-1] o.s.boot.SpringApplication               : No active profile set, falling back to 1 default profile: "default"
    2022-06-24 22:34:31.985  INFO 8084 --- [       Thread-1] org.quartz.impl.StdSchedulerFactory      : Using default implementation for ThreadExecutor
    2022-06-24 22:34:31.991  INFO 8084 --- [       Thread-1] org.quartz.core.SchedulerSignalerImpl    : Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
    2022-06-24 22:34:31.991  INFO 8084 --- [       Thread-1] org.quartz.core.QuartzScheduler          : Quartz Scheduler v.2.3.2 created.
    2022-06-24 22:34:31.991  INFO 8084 --- [       Thread-1] org.quartz.simpl.RAMJobStore             : RAMJobStore initialized.
    2022-06-24 22:34:31.992  INFO 8084 --- [       Thread-1] org.quartz.core.QuartzScheduler          : Scheduler meta-data: Quartz Scheduler (v2.3.2) 'quartzScheduler' with instanceId 'NON_CLUSTERED'
    Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
    NOT STARTED.
    Currently in standby mode.
    Number of jobs executed: 0
    Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
    Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.

    2022-06-24 22:34:31.992  INFO 8084 --- [       Thread-1] org.quartz.impl.StdSchedulerFactory      : Quartz scheduler 'quartzScheduler' initialized from an externally provided properties instance.
    2022-06-24 22:34:31.992  INFO 8084 --- [       Thread-1] org.quartz.impl.StdSchedulerFactory      : Quartz scheduler version: 2.3.2
    2022-06-24 22:34:31.992  INFO 8084 --- [       Thread-1] org.quartz.core.QuartzScheduler          : JobFactory set to: org.springframework.scheduling.quartz.SpringBeanJobFactory@501627dc
    2022-06-24 22:34:32.009  INFO 8084 --- [       Thread-1] o.s.s.quartz.SchedulerFactoryBean        : Starting Quartz Scheduler now
    2022-06-24 22:34:32.010  INFO 8084 --- [       Thread-1] org.quartz.core.QuartzScheduler          : Scheduler quartzScheduler_$_NON_CLUSTERED started.
    2022-06-24 22:34:32.015  INFO 8084 --- [       Thread-1] o.s.boot.SpringApplication               : Started application in 0.601 seconds (JVM running for 1.051)
    org.springframework.context.annotation.AnnotationConfigApplicationContext@74ed4e3, started on Fri Jun 24 22:34:31 MSK 2022
    org.springframework.context.annotation.AnnotationConfigApplicationContext@74ed4e3, started on Fri Jun 24 22:34:31 MSK 2022
    org.springframework.context.annotation.AnnotationConfigApplicationContext@74ed4e3, started on Fri Jun 24 22:34:31 MSK 2022
and so on...

只有 1 个依赖项（只是随机启动器，不是 Web，这里不需要石英）

org.springframework.boot:spring-boot-starter-quartz

只是非守护线程中的无限循环...

匿名用户

回答问题

Spring启动启动器网络阻止Spring启动退出的代码是什么

spring-boot-web 创建 Web 服务器 bean，它使用非守护进程侦听器线程（因为您希望它们处于活动状态并运行以等待传入连接并处理它们）。

这使得您的代码到达< code>main方法的末尾，但是JVM不会退出，因为它有非守护线程在运行。

如果你想让你的应用程序保持活力，你也需要这样做——最简单的方法是在一个bean中创建一个线程，就像@Slongtong建议的那样。