spring-boot启动源码

1 运行SpringApplication.run()方法
--- org.springframework.boot.SpringApplication.SpringApplication(org.springframework.core.io.ResourceLoader, java.lang.Class<?>...)

2 确定应用程序类型
this.webApplicationType = WebApplicationType.deduceFromClasspath();

3 加载所有的初始化器
  配置在spring-boot-autoconfigure 和 spring-boot 的spring.factories里

  自定义初始化器：
  a)实现 ApplicationContextInitializer接口 b)META-INF/spring.factories 配置文件

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import org.springframework.context.ApplicationContextInitializer; import org.springframework.context.ConfigurableApplicationContext;   /**  * 初始化器  */ public class MyApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {     @Override     public void initialize(ConfigurableApplicationContext configurableApplicationContext) {         System.out.println("我是初始化的 MyApplicationContextInitializer...");     } }

　　配置

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1 2	org.springframework.context.ApplicationContextInitializer=\ com.application.MyApplicationContextInitializer

　　

4、加载所有的监听器
  配置在spring-boot-autoconfigure 和 spring-boot 的spring.factories里
  监听器加载的是实现了ApplicationListener 接口的类


5 设置运行的主类

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--- org.springframework.boot.SpringApplication.run(java.lang.String...)     public ConfigurableApplicationContext run(String... args) {         //开启计时器         StopWatch stopWatch = new StopWatch();         stopWatch.start();           ConfigurableApplicationContext context = null;         Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();         configureHeadlessProperty();           //获取并启动监听器         SpringApplicationRunListeners listeners = getRunListeners(args);         listeners.starting();         try {               //设置应用程序参数，main方法里面执行静态run方法传入的参数             ApplicationArguments applicationArguments = new DefaultApplicationArguments(                     args);               //准备环境变量，将maven和系统的环境变量都加载进来了             ConfigurableEnvironment environment = prepareEnvironment(listeners,                     applicationArguments);             configureIgnoreBeanInfo(environment);               Banner printedBanner = printBanner(environment);               //反射创建应用程序上下文             context = createApplicationContext();               //*实例化异常报告器。自定义异常报告器：继承 SpringBootExceptionReporter 接口             //*1 开启异常报警器             exceptionReporters = getSpringFactoriesInstances(                     SpringBootExceptionReporter.class,                     new Class[] { ConfigurableApplicationContext.class }, context);               //*2 以下代码中发生异常都会执行异常报警器               //准备上下文环境，为下一步刷新作准备：postProcessApplicationContext、applyInitializers、registerSingleton             prepareContext(context, environment, listeners, applicationArguments,                     printedBanner);               //刷新上下文，属于spring范畴，自动装配和启动tomcat             refreshContext(context);               //后置处理，留给用户扩展使用             afterRefresh(context, applicationArguments);               //结束计时器             stopWatch.stop();               if (this.logStartupInfo) {                 new StartupInfoLogger(this.mainApplicationClass)                         .logStarted(getApplicationLog(), stopWatch);             }               //发布上下文准备就绪事件             listeners.started(context);               //扩展功能，启动自定义的run方法             callRunners(context, applicationArguments);         }         catch (Throwable ex) {             //3 捕获异常并调用异常报警器方法             handleRunFailure(context, ex, exceptionReporters, listeners);             throw new IllegalStateException(ex);         }           try {             listeners.running(context);         }         catch (Throwable ex) {             handleRunFailure(context, ex, exceptionReporters, null);             throw new IllegalStateException(ex);         }         return context;     }

　

* 自定义异常报告器
  配置在spring.factories里
  监听器加载的是实现了 SpringBootExceptionReporter 接口的类

自定义异常报告器

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import org.springframework.boot.SpringBootExceptionReporter; import org.springframework.context.ConfigurableApplicationContext;   public class MyExceptionReporter implements SpringBootExceptionReporter {       private ConfigurableApplicationContext context;       // 必须要有一个有参的构造函数，否则启动会报错     MyExceptionReporter(ConfigurableApplicationContext context) {         this.context = context;     }       @Override     public boolean reportException(Throwable failure) {         System.out.println("进入异常报告器");         failure.printStackTrace();         // 返回false会打印详细springboot错误信息，返回true则只打印异常信息         return false;     } }

　　配置

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1 2	org.springframework.boot.SpringBootExceptionReporter=\ com.baoyun.iyb.config.application.MyExceptionReporter

　

* 执行自定义的run方法
  1。实现 ApplicationRunner 接口
  2。实现 CommandLineRunner 接口
  com.init.MyRunner

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import org.springframework.boot.ApplicationArguments; import org.springframework.boot.ApplicationRunner; import org.springframework.boot.CommandLineRunner;   public class MyRunner implements ApplicationRunner, CommandLineRunner {       @Override     public void run(ApplicationArguments args) throws Exception {         System.out.println(" 我是自定义的run方法1，实现 ApplicationRunner 接口既可运行"        );     }       @Override     public void run(String... args) throws Exception {         System.out.println(" 我是自定义的run方法2，实现 CommandLineRunner 接口既可运行"        );     } }