通知 网站从因情语写改为晴雨,这个网站的模板也从calmlog_ex改为 whimurmur

尚硅谷springboot学习35-启动原理

1076人浏览 / 0人评论 / | 作者:因情语写  | 分类: springboot  | 标签: 框架  /  springboot  | 

作者:因情语写

链接:https://www.proprogrammar.com/article/359

声明:请尊重原作者的劳动,如需转载请注明出处


  先列出几个重要的事件回调机制

  配置在META-INF/spring.factories

  ApplicationContextInitializer

  SpringApplicationRunListener

  只需要放在ioc容器中

  ApplicationRunner

  CommandLineRunner

   启动流程:

  1、创建SpringApplication对象

initialize(sources);

private void initialize(Object[] sources) {
    //保存主配置类
    if (sources != null && sources.length > 0) {
        this.sources.addAll(Arrays.asList(sources));
    }
    //判断当前是否一个web应用
    this.webEnvironment = deduceWebEnvironment();
    //从类路径下找到META-INF/spring.factories配置的所有ApplicationContextInitializer;然后保存起来
    setInitializers((Collection) getSpringFactoriesInstances(
        ApplicationContextInitializer.class));
    //从类路径下找到ETA-INF/spring.factories配置的所有ApplicationListener
    setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
    //从多个配置类中找到有main方法的主配置类
    this.mainApplicationClass = deduceMainApplicationClass();
}

  

  2、运行run方法

public ConfigurableApplicationContext run(String... args) {
   StopWatch stopWatch = new StopWatch();
   stopWatch.start();
   ConfigurableApplicationContext context = null;
   FailureAnalyzers analyzers = null;
   configureHeadlessProperty();
    
   //获取SpringApplicationRunListeners;从类路径下META-INF/spring.factories
   SpringApplicationRunListeners listeners = getRunListeners(args);
    //回调所有的获取SpringApplicationRunListener.starting()方法
   listeners.starting();
   try {
       //封装命令行参数
      ApplicationArguments applicationArguments = new DefaultApplicationArguments(
            args);
      //准备环境
      ConfigurableEnvironment environment = prepareEnvironment(listeners,
            applicationArguments);
               //创建环境完成后回调SpringApplicationRunListener.environmentPrepared();表示环境准备完成
       
      Banner printedBanner = printBanner(environment);
       
       //创建ApplicationContext;决定创建web的ioc还是普通的ioc
      context = createApplicationContext();
       
      analyzers = new FailureAnalyzers(context);
       //准备上下文环境;将environment保存到ioc中;而且applyInitializers();
       //applyInitializers():回调之前保存的所有的ApplicationContextInitializer的initialize方法
       //回调所有的SpringApplicationRunListener的contextPrepared();
       //
      prepareContext(context, environment, listeners, applicationArguments,
            printedBanner);
       //prepareContext运行完成以后回调所有的SpringApplicationRunListener的contextLoaded();
       
       //s刷新容器;ioc容器初始化(如果是web应用还会创建嵌入式的Tomcat);Spring注解版
       //扫描,创建,加载所有组件的地方;(配置类,组件,自动配置)
      refreshContext(context);
       //从ioc容器中获取所有的ApplicationRunner和CommandLineRunner进行回调
       //ApplicationRunner先回调,CommandLineRunner再回调
      afterRefresh(context, applicationArguments);
       //所有的SpringApplicationRunListener回调finished方法
      listeners.finished(context, null);
      stopWatch.stop();
      if (this.logStartupInfo) {
         new StartupInfoLogger(this.mainApplicationClass)
               .logStarted(getApplicationLog(), stopWatch);
      }
       //整个SpringBoot应用启动完成以后返回启动的ioc容器;
      return context;
   }
   catch (Throwable ex) {
      handleRunFailure(context, listeners, analyzers, ex);
      throw new IllegalStateException(ex);
   }
}

  3、事件监听机制

  配置在META-INF/spring.factories

  ApplicationContextInitializer

public class HelloApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        System.out.println("ApplicationContextInitializer...initialize..."+applicationContext);
    }
}

  SpringApplicationRunListener

public class HelloSpringApplicationRunListener implements SpringApplicationRunListener {

    //必须有的构造器
    public HelloSpringApplicationRunListener(SpringApplication application, String[] args){

    }

    @Override
    public void starting() {
        System.out.println("SpringApplicationRunListener...starting...");
    }

    @Override
    public void environmentPrepared(ConfigurableEnvironment environment) {
        Object o = environment.getSystemProperties().get("os.name");
        System.out.println("SpringApplicationRunListener...environmentPrepared.."+o);
    }

    @Override
    public void contextPrepared(ConfigurableApplicationContext context) {
        System.out.println("SpringApplicationRunListener...contextPrepared...");
    }

    @Override
    public void contextLoaded(ConfigurableApplicationContext context) {
        System.out.println("SpringApplicationRunListener...contextLoaded...");
    }

    @Override
    public void finished(ConfigurableApplicationContext context, Throwable exception) {
        System.out.println("SpringApplicationRunListener...finished...");
    }
}

  配置(META-INF/spring.factories)  

org.springframework.context.ApplicationContextInitializer=\
com.atguigu.springboot.listener.HelloApplicationContextInitializer

org.springframework.boot.SpringApplicationRunListener=\
com.atguigu.springboot.listener.HelloSpringApplicationRunListener

  下面两个只需要放在ioc容器中

  ApplicationRunner

@Component
public class HelloApplicationRunner implements ApplicationRunner {
    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println("ApplicationRunner...run....");
    }
}

  CommandLineRunner

@Component
public class HelloCommandLineRunner implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        System.out.println("CommandLineRunner...run..."+ Arrays.asList(args));
    }
}

  看一下启动的效果

SpringApplicationRunListener...starting...
SpringApplicationRunListener...environmentPrepared..Windows 8.1

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::       (v1.5.10.RELEASE)

ApplicationContextInitializer...initialize...org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@140e5a13: startup date [Thu Jan 01 08:00:00 CST 1970]; root of context hierarchy
SpringApplicationRunListener...contextPrepared...
2019-02-09 02:04:54.489  INFO 8068 --- [           main] c.a.springboot.SpringBoot07Application   : Starting SpringBoot07Application on DESKTOP-1IMBL43 with PID 8068 (started by DELL in H:\source-code\src\java-code\javaweb\springboot\基础\spring-boot-07)
2019-02-09 02:04:54.493  INFO 8068 --- [           main] c.a.springboot.SpringBoot07Application   : No active profile set, falling back to default profiles: default
SpringApplicationRunListener...contextLoaded...
2019-02-09 02:04:54.583  INFO 8068 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@140e5a13: startup date [Sat Feb 09 02:04:54 CST 2019]; root of context hierarchy
2019-02-09 02:04:57.715  INFO 8068 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2019-02-09 02:04:57.729  INFO 8068 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-02-09 02:04:57.730  INFO 8068 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.27
2019-02-09 02:04:57.947  INFO 8068 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-02-09 02:04:57.947  INFO 8068 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 3365 ms
2019-02-09 02:04:58.247  INFO 8068 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2019-02-09 02:04:58.255  INFO 8068 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2019-02-09 02:04:58.256  INFO 8068 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2019-02-09 02:04:58.257  INFO 8068 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2019-02-09 02:04:58.257  INFO 8068 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2019-02-09 02:04:58.874  INFO 8068 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@140e5a13: startup date [Sat Feb 09 02:04:54 CST 2019]; root of context hierarchy
2019-02-09 02:04:59.148  INFO 8068 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2019-02-09 02:04:59.160  INFO 8068 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2019-02-09 02:04:59.291  INFO 8068 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2019-02-09 02:04:59.292  INFO 8068 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2019-02-09 02:04:59.428  INFO 8068 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2019-02-09 02:04:59.955  INFO 8068 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2019-02-09 02:05:00.121  INFO 8068 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
ApplicationRunner...run....
CommandLineRunner...run...[]
SpringApplicationRunListener...finished...
2019-02-09 02:05:00.128  INFO 8068 --- [           main] c.a.springboot.SpringBoot07Application   : Started SpringBoot07Application in 6.117 seconds (JVM running for 6.742)

 


亲爱的读者:有时间可以点赞评论一下

点赞(0) 打赏

全部评论

还没有评论!
广告位-帮帮忙点下广告