以编程方式重新启动Spring Boot应用程序/刷新Spring Context

问题描述

我试图以编程方式重新启动我的Spring应用程序，而无需用户干预。

I am trying to programatically restart my Spring Application without having the user to intervene.

基本上，我有一个允许切换应用程序模式的页面（实际上意味着切换当前活动的配置文件）并且据我所知，我必须重新启动上下文。

Basically, I have a page which allows to switch the mode of the application (actually meaning switching the currently active profile) and as far as I understand I must restart the context.

目前我的代码非常简单，它仅用于重启位（这个顺便说一句是Kotlin）：

Currently my code is very simple, it's just for the restarting bit (this is Kotlin by the way):

    context.close()
    application.setEnvironment(context.environment)
    ClassUtils.overrideThreadContextClassLoader(application.javaClass.classLoader)
    context = application.run(*argsArray)

但是，当我做 context.close（）时，JVM立即存在。我也尝试了 context.refresh（）但这似乎只是杀死了Tomcat / Jetty（只是在遇到Tomcat问题的情况下尝试了）然后没有任何反应。

However the moment I do context.close() the JVM exists immediately. I have also tried context.refresh() but that seems to simply kill Tomcat/Jetty (tried both just in case it was a Tomcat problem) and then nothing happens.

我还看过但这些答案对我来说似乎没什么用处。此外，我查看了Spring Actuator，它应该有 / restart 端点，但那似乎不再存在了？

I have also seen Programmatically restart Spring Boot application but nothing seems to work for me from those answers. Furthermore, I looked into Spring Actuator which supposedly has the /restart endpoint, but that doesn't seem to be there anymore?

非常感谢帮助。谢谢。

推荐答案

即使Alex的解决方案有效，我也不相信包含2个额外的依赖项（ Actuator 和 Cloud Context ）只是为了能够进行一项操作。相反，我已经结合他的答案并修改了我的代码，以便做我想做的事。

Even though Alex's solution works, I don't believe in including 2 additional dependencies (Actuator and Cloud Context) just to be able to do one operation. Instead, I have combined his answer and modified my code in order to do what I wanted.

所以，首先，它是至关重要代码是使用 new Thread（）和 setDaemon（false）; 执行的。我有以下处理重启的端点方法：

So, first of all, it is crucial that the code is executed using new Thread() and setDaemon(false);. I have the following endpoint method that handles the restart:

val restartThread = Thread {
    logger.info("Restarting...")
    Thread.sleep(1000)
    SpringMain.restartToMode(AppMode.valueOf(change.newMode.toUpperCase()))
    logger.info("Restarting... Done.")
}
restartThread.isDaemon = false
restartThread.start()

不需要 Thread.sleep（1000），但我希望我的控制器在实际重启应用程序之前输出视图。

The Thread.sleep(1000) is not required, but I want my controller to output the view before actually restarting the application.

SpringMain.restartToMode 具有以下内容：

@Synchronized fun restartToMode(mode: AppMode) {
    requireNotNull(context)
    requireNotNull(application)

    // internal logic to potentially produce a new arguments array

    // close previous context
    context.close()

    // and build new one using the new mode
    val builder = SpringApplicationBuilder(SpringMain::class.java)
    application = builder.application()
    context = builder.build().run(*argsArray)
}

其中上下文和应用程序在启动应用程序时来自 main 方法：

Where context and application come from the main method upon starting the application:

val args = ArrayList<String>()
lateinit var context: ConfigurableApplicationContext
lateinit var application: SpringApplication

@Throws(Exception::class)
@JvmStatic fun main(args: Array<String>) {
    this.args += args

    val builder = SpringApplicationBuilder(SpringMain::class.java)
    application = builder.application()
    context = builder.build().run(*args)
}

我不完全确定这是否会产生任何问题。如果有，我会更新这个答案。希望这对其他人有任何帮助。

I am not entirely sure if this produces any problems. If there will be, I will update this answer. Hopefully this will be of any help to others.

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