在spring-mvc应用程序启动时运行一个类

问题描述：

是否有可能在应用程序启动时运行一个类时mvc 我想初始化该类中的线程？在spring-mvc应用程序启动时运行一个类

还是有什么办法..？

   public class MyServletContextListener implements Runnable { 



      public void run() { 

       while (true) { 

       try { 
        System.out.println("Inside run()"); 
        Thread.sleep(10000); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
       } 


      } 

      }

这种输出增加ApplicationListener接口的

  NFO: HHH000206: hibernate.properties not found 
      Jul 24, 2017 8:42:33 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit> 
      INFO: HCANN000001: Hibernate Commons Annotations {5.0.1.Final} 
      Jul 24, 2017 8:42:35 PM org.hibernate.dialect.Dialect <init> 
      INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect 
      Jul 24, 2017 8:42:36 PM org.hibernate.engine.jdbc.env.internal.LobCreatorBuilderImpl useContextualLobCreation 
      INFO: HHH000423: Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4 

      Thread Started 
      getApplicationName() : /Hibernate_webservice 
      getId() : org.springframework.web.context.WebApplicationContext:/Hibernate_webservice 
      getParent() : null 
      getDisplayName() : Root WebApplicationContext 


      Jul 24, 2017 8:42:38 PM org.springframework.web.context.ContextLoader initWebApplicationContext 
      INFO: Root WebApplicationContext: initialization completed in 8880 ms 
      Jul 24, 2017 8:42:38 PM org.apache.catalina.core.ApplicationContext log 
      INFO: Initializing Spring FrameworkServlet 'appServlet' 
      Jul 24, 2017 8:42:38 PM org.springframework.web.servlet.DispatcherServlet initServletBean 
      INFO: FrameworkServlet 'appServlet': initialization started 
      Jul 24, 2017 8:42:38 PM org.springframework.web.context.support.XmlWebApplicationContext prepareRefresh 
      INFO: Refreshing WebApplicationContext for namespace 'appServlet-servlet': startup date [Mon Jul 24 20:42:38 IST 2017]; parent: Root WebApplicationContext 
      Jul 24, 2017 8:42:38 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 
      INFO: Loading XML bean definitions from ServletContext resource [/WEB-INF/spring-config.xml] 
      Jul 24, 2017 8:42:38 PM org.springframework.context.support.PropertySourcesPlaceholderConfigurer loadProperties 
      INFO: Loading properties file from class path resource [application.properties] 
      Jul 24, 2017 8:42:38 PM org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor <init> 
      INFO: JSR-330 'javax.inject.Inject' annotation found and supported for autowiring 
      Jul 24, 2017 8:42:38 PM org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping registerHandlerMethod 
      INFO: Mapped "{[/form],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public org.springframework.web.servlet.ModelAndView sample.test.TestController.method() 
      Jul 24, 2017 8:42:39 PM org.hibernate.dialect.Dialect <init> 
      INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect 
      Jul 24, 2017 8:42:39 PM org.hibernate.engine.jdbc.env.internal.LobCreatorBuilderImpl useContextualLobCreation 
      INFO: HHH000423: Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4 

      Thread Started 
      getApplicationName() : /Hibernate_webservice 
      getId() : org.springframework.web.context.WebApplicationContext:/Hibernate_webservice/appServlet 
      getParent() : Root WebApplicationContext: startup date [Mon Jul 24 20:42:30 IST 2017]; root of context hierarchy 
      getDisplayName() : WebApplicationContext for namespace 'appServlet-servlet' 



      Thread Started 
      getApplicationName() : /Hibernate_webservice 
      getId() : org.springframework.web.context.WebApplicationContext:/Hibernate_webservice/appServlet 
      getParent() : Root WebApplicationContext: startup date [Mon Jul 24 20:42:30 IST 2017]; root of context hierarchy 
      getDisplayName() : WebApplicationContext for namespace 'appServlet-servlet' 


      Jul 24, 2017 8:42:39 PM org.springframework.web.servlet.DispatcherServlet initServletBean 
      INFO: FrameworkServlet 'appServlet': initialization completed in 1365 ms 
      Jul 24, 2017 8:42:40 PM org.apache.coyote.AbstractProtocol start 
      INFO: Starting ProtocolHandler ["http-nio-8082"] 
      Jul 24, 2017 8:42:40 PM org.apache.coyote.AbstractProtocol start 
      INFO: Starting ProtocolHandler ["ajp-nio-8011"] 
      Jul 24, 2017 8:42:40 PM org.apache.catalina.startup.Catalina start 
      INFO: Server startup in 19807 ms

答

春节后，我得到了提供ApplicationListener<ContextRefreshedEvent>接口及其onApplicationEvent(ContextRefreshedEvent event)钩。

例如：

@Component 
public class MyServiceCreationListener implements ApplicationListener<ContextRefreshedEvent> { 

    @Override 
    public void onApplicationEvent(ContextRefreshedEvent event) { 
     // do something on container startup 
    } 
}

无论你在onApplicationEvent方法写会被执行一次且仅一次创建Spring上下文时。

如果您发现此方法被多次调用，那么您必须具有多个ApplicationContext。如果你检查event.getApplicationContext()你可能会看到他们每个人都有一个不同的ID和displayName，你可以找出他们的起源。如果你的是Spring MVC应用程序，那么你可能同时拥有一个ContextLoaderListener和DispatcherServlet，这两个都创建它们自己的ApplicationContext，每个都会触发一个ContextRefreshedEvent。

如果你想确定哪个是父上下文，你可以尝试event.getApplicationContext().getParent() != null，或者你可以在你的ApplicationListener中切换一个布尔类，例如： alreadyInitialised。

还有Spring 4的SmartInitializingSingleton这可能允许您挂钩到不同级别的上下文创建。

此解决方案正在工作，但它在应用程序加载时调用onApplicationEvent（ContextRefreshedEvent event）3次 –

我已经更新了答案，以描述如何多次触发ContextRefreshedEvent并提供有关如何避免/处理该问题的一些建议。 – glytching

有多个应用程序上下文是很好的...如果我只需要一个上下文，该怎么办？ –

答

通过扩展Thread创建一个简单的Java线程，并由Spring的容器通过@Component.管理。bean的范围必须是“prototype”，以便每个请求都会返回一个新实例，以运行每个单独的线程。

PrintThread.java: 

package com.mkyong.thread; 

import org.springframework.context.annotation.Scope; 
import org.springframework.stereotype.Component; 

@Component 
@Scope("prototype") 
public class PrintThread extends Thread{ 

    @Override 
    public void run() { 

     System.out.println(getName() + " is running"); 
     try { 
      Thread.sleep(5000); 
     } catch (InterruptedException e) { 
      e.printStackTrace(); 
     } 
     System.out.println(getName() + " is running"); 
    } 

} 

AppConfig.java: 

package com.mkyong.config; 

import org.springframework.context.annotation.ComponentScan; 
import org.springframework.context.annotation.Configuration; 

@Configuration 
@ComponentScan(basePackages="com.mkyong.thread") 
public class AppConfig{ 
} 

App.java: 

package com.mkyong; 

import org.springframework.context.ApplicationContext; 
import org.springframework.context.annotation.AnnotationConfigApplicationContext; 

import com.mkyong.config.AppConfig; 
import com.mkyong.thread.PrintThread; 

public class App 
{ 
    public static void main(String[] args) 
    { 

     ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class); 

     PrintThread printThread1 = (PrintThread) ctx.getBean("printThread"); 
     printThread1.setName("Thread 1"); 

     PrintThread printThread2 = (PrintThread) ctx.getBean("printThread"); 
     printThread2.setName("Thread 2"); 

     PrintThread printThread3 = (PrintThread) ctx.getBean("printThread"); 
     printThread3.setName("Thread 3"); 

     PrintThread printThread4 = (PrintThread) ctx.getBean("printThread"); 
     printThread4.setName("Thread 4"); 

     PrintThread printThread5 = (PrintThread) ctx.getBean("printThread"); 
     printThread5.setName("Thread 5"); 

     printThread1.start(); 
     printThread2.start(); 
     printThread3.start(); 
     printThread4.start(); 
     printThread5.start(); 

    } 
}

输出 - 订货会，每次变化，这是线程:)

Thread 3 is running 
Thread 2 is running 
Thread 1 is running 
Thread 5 is running 
Thread 4 is running 
Thread 2 is running 
Thread 4 is running 
Thread 5 is running 
Thread 3 is running 
Thread 1 is running

希望这有助于:)

答

您可以添加应用程序监听器（A类实现上下文监听器接口）创建你的线程没有头痛如果你正在创建时间表，你可以使用石英或弹簧计时器

在spring-mvc应用程序启动时运行一个类

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