即使在添加了@Autowire之后，如果你的类不是一个RestController或Configuration class, applicationContext对象仍然是空的。尝试用下面创建新类，它工作正常:

@Component
public class SpringContext implements ApplicationContextAware{

   private static ApplicationContext applicationContext;

   @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws 
     BeansException {
    this.applicationContext=applicationContext;
   }
 }

然后，你可以在同一个类中根据你的需要实现一个getter方法，比如通过:

    applicationContext.getBean(String serviceName,Interface.Class)

我知道这个问题已经有了答案，但是我想分享一下我用来检索Spring Context的Kotlin代码。

我不是专家，所以我愿意接受批评、评论和建议:

https://gist.github.com/edpichler/9e22309a86b97dbd4cb1ffe011aa69dd

package com.company.web.spring

import com.company.jpa.spring.MyBusinessAppConfig
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.ApplicationContext
import org.springframework.context.annotation.AnnotationConfigApplicationContext
import org.springframework.context.annotation.ComponentScan
import org.springframework.context.annotation.Configuration
import org.springframework.context.annotation.Import
import org.springframework.stereotype.Component
import org.springframework.web.context.ContextLoader
import org.springframework.web.context.WebApplicationContext
import org.springframework.web.context.support.WebApplicationContextUtils
import javax.servlet.http.HttpServlet

@Configuration
@Import(value = [MyBusinessAppConfig::class])
@ComponentScan(basePackageClasses  = [SpringUtils::class])
open class WebAppConfig {
}

/**
 *
 * Singleton object to create (only if necessary), return and reuse a Spring Application Context.
 *
 * When you instantiates a class by yourself, spring context does not autowire its properties, but you can wire by yourself.
 * This class helps to find a context or create a new one, so you can wire properties inside objects that are not
 * created by Spring (e.g.: Servlets, usually created by the web server).
 *
 * Sometimes a SpringContext is created inside jUnit tests, or in the application server, or just manually. Independent
 * where it was created, I recommend you to configure your spring configuration to scan this SpringUtils package, so the 'springAppContext'
 * property will be used and autowired at the SpringUtils object the start of your spring context, and you will have just one instance of spring context public available.
 *
 *Ps: Even if your spring configuration doesn't include the SpringUtils @Component, it will works tto, but it will create a second Spring Context o your application.
 */
@Component
object SpringUtils {

        var springAppContext: ApplicationContext? = null
    @Autowired
    set(value) {
        field = value
    }



    /**
     * Tries to find and reuse the Application Spring Context. If none found, creates one and save for reuse.
     * @return returns a Spring Context.
     */
    fun ctx(): ApplicationContext {
        if (springAppContext!= null) {
            println("achou")
            return springAppContext as ApplicationContext;
        }

        //springcontext not autowired. Trying to find on the thread...
        val webContext = ContextLoader.getCurrentWebApplicationContext()
        if (webContext != null) {
            springAppContext = webContext;
            println("achou no servidor")
            return springAppContext as WebApplicationContext;
        }

        println("nao achou, vai criar")
        //None spring context found. Start creating a new one...
        val applicationContext = AnnotationConfigApplicationContext ( WebAppConfig::class.java )

        //saving the context for reusing next time
        springAppContext = applicationContext
        return applicationContext
    }

    /**
     * @return a Spring context of the WebApplication.
     * @param createNewWhenNotFound when true, creates a new Spring Context to return, when no one found in the ServletContext.
     * @param httpServlet the @WebServlet.
     */
    fun ctx(httpServlet: HttpServlet, createNewWhenNotFound: Boolean): ApplicationContext {
        try {
            val webContext = WebApplicationContextUtils.findWebApplicationContext(httpServlet.servletContext)
            if (webContext != null) {
                return webContext
            }
            if (createNewWhenNotFound) {
                //creates a new one
                return ctx()
            } else {
                throw NullPointerException("Cannot found a Spring Application Context.");
            }
        }catch (er: IllegalStateException){
            if (createNewWhenNotFound) {
                //creates a new one
                return ctx()
            }
            throw er;
        }
    }
}

现在，spring上下文是公开可用的，能够独立于上下文调用相同的方法(junit测试，bean，手动实例化类)，就像下面这个Java Servlet:

@WebServlet(name = "MyWebHook", value = "/WebHook")
public class MyWebServlet extends HttpServlet {


    private MyBean byBean
            = SpringUtils.INSTANCE.ctx(this, true).getBean(MyBean.class);


    public MyWebServlet() {

    }
}

即使在添加了@Autowire之后，如果你的类不是一个RestController或Configuration class, applicationContext对象仍然是空的。尝试用下面创建新类，它工作正常:

@Component
public class SpringContext implements ApplicationContextAware{

   private static ApplicationContext applicationContext;

   @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws 
     BeansException {
    this.applicationContext=applicationContext;
   }
 }

然后，你可以在同一个类中根据你的需要实现一个getter方法，比如通过:

    applicationContext.getBean(String serviceName,Interface.Class)

如果你使用的是web应用，还有另一种不使用单例的方式来访问应用上下文，那就是使用servletfilter和ThreadLocal。在过滤器中，您可以使用WebApplicationContextUtils访问应用程序上下文，并在TheadLocal中存储应用程序上下文或所需的bean。

警告:如果你忘记撤消ThreadLocal，你将在尝试撤消应用程序时遇到严重的问题!因此，您应该设置它，并立即开始尝试，在最后部分取消对ThreadLocal的设置。

当然，这仍然使用一个单例:ThreadLocal。但实际的豆子不需要再这样了。它甚至可以是请求范围的，如果应用程序中有多个war，并且EAR中的库也可以使用此解决方案。不过，您可能会认为ThreadLocal的这种使用与普通单例的使用一样糟糕。；-）

也许Spring已经提供了类似的解决方案?我没有找到，但我不确定。

我使用一种简单、标准化的方法允许外部访问我自己的任何单例Spring bean。使用这个方法，我继续让Spring实例化Bean。我是这么做的:

定义与外围类类型相同的私有静态变量。 在类的每个构造函数中将该变量设置为this。如果类没有构造函数，则添加一个用于设置变量的默认构造函数。 定义一个返回单例变量的公共静态getter方法。

这里有一个例子:

@Component
public class MyBean {
    ...

    private static MyBean singleton = null;

    public MyBean() {
        ...
        singleton = this;
    }

    ...
    
    public void someMethod() {
        ...
    }

    ...

    public static MyBean get() {
        return singleton;
    }
}

然后我可以在单例bean上调用someMethod，在我代码中的任何地方，通过:

MyBean.get().someMethod();

如果您已经子类化了您的ApplicationContext，您可以直接将这种机制添加到它中。否则，您可以子类化它来完成这个任务，或者将这个机制添加到任何可以访问ApplicationContext的bean中，然后使用它来从任何地方访问ApplicationContext。重要的是，正是这个机制让您能够进入Spring环境。

不确定这有多有用，但你也可以在初始化应用程序时获得上下文。这是最快的你可以获得上下文，甚至在@Autowire之前。

@SpringBootApplication
public class Application extends SpringBootServletInitializer {
    private static ApplicationContext context;

    // I believe this only runs during an embedded Tomcat with `mvn spring-boot:run`. 
    // I don't believe it runs when deploying to Tomcat on AWS.
    public static void main(String[] args) {
        context = SpringApplication.run(Application.class, args);
        DataSource dataSource = context.getBean(javax.sql.DataSource.class);
        Logger.getLogger("Application").info("DATASOURCE = " + dataSource);