thisapplicationfailed,webapplicationinitializer
自动spring应用程序
spring应用程序是springboot驱动spring APP应用程序上下文的引导类
@ springbootconfiguration @ enableautoconfiguration @ components can (exclude filters={ @ filter (type=filter type.custom ) @filter(type=filtertype.custom，classes=autoconfigurationexcludefilter.classes是在哪个版本中引入的？ spring框架3.1
@EnableAutoConfiguration :以激励自动组装@Enable-@Enable开头
(1) @EnableWebMvc
(2) @启用转换管理
(3) @EnableAspectJAutoProxy
)4)启用同步
@SpringBootConfiguration:等效于@ configuration-configuration class注释
@Component的“派生性”
@Component
@Component - @ComponentScan
处理系统- ConfigurationClassParser
扫描类-
ClassPathBeanDefinitionScanner
classpathscanningcandidatecomponentprovider
protectedvoidregisterdefaultfilters ((this.include filters.add ) newannotationtypefilter ) component.class )； dubbo @ service-2.5.7-newannotationtypefilter (service.class )；
Spring注释编程模型
@Component
@Service
@ component public @接口服务{ . } @ repository
@ component public @接口存储库{ . } @ controller
@ component public @接口控制器{ . } @ configuration
@ component public @ interface configuration { . } spring模式注释： Stereotype Annotations
Spring注释驱动示例
注释驱动上下文从annotationconfigapplicationcontext，Spring Framework 3.0引入
@ configurationpublicclassspringannotationdemo {
publicstaticvoidmain (字符串[ ] args )/XML配置文件驱动classpathxmlapplicationcontext//annotation驱动BeanDefinition //查找@ bean @ configurationannotationconfigapplicationcontextcontext=newannotationconfigapplicationcontext； 注册//configuration class=springannotationdemocontext.register (springannotationdemo.class )； //上下文启动context.refresh (； system.out.println (context.get bean (springannotationdemo.class ) )； } }@SpringBootApplication标注的当前功能
@SpringBootApplication
@SpringBootConfiguration
@Configuration
@Component
SpringApplication Spring Boot 应用的引导
基本写法
SpringApplication springApplication = new SpringApplication(MicroservicesProjectApplication.class); Map<String,Object> properties = new LinkedHashMap<>(); properties.put("server.port",0); springApplication.setDefaultProperties(properties); springApplication.run(args);
SpringApplicationBuilder
new SpringApplicationBuilder(MicroservicesProjectApplication.class) // Fluent API // 单元测试是 PORT = RANDOM .properties("server.port=0") // 随机向 OS 要可用端口 .run(args);Spring Boot 引导示例
@SpringBootApplicationpublic class MicroservicesProjectApplication {
public static void main(String[] args) { SpringApplication springApplication = new SpringApplication(MicroservicesProjectApplication.class); Map<String,Object> properties = new LinkedHashMap<>(); properties.put("server.port",0); springApplication.setDefaultProperties(properties); ConfigurableApplicationContext context = springApplication.run(args); // 有异常？ System.out.println(context.getBean(MicroservicesProjectApplication.class));}}
调整示例为 非 Web 程序
@SpringBootApplicationpublic class MicroservicesProjectApplication {
public static void main(String[] args) { SpringApplication springApplication = new SpringApplication(MicroservicesProjectApplication.class); Map<String, Object> properties = new LinkedHashMap<>(); properties.put("server.port", 0); springApplication.setDefaultProperties(properties); // 设置为 非 web 应用 springApplication.setWebApplicationType(WebApplicationType.NONE); ConfigurableApplicationContext context = springApplication.run(args); // 有异常？ System.out.println(context.getBean(MicroservicesProjectApplication.class)); // 输出当前 Spring Boot 应用的 ApplicationContext 的类名 System.out.println("当前 Spring 应用上下文的类：" + context.getClass().getName());}}输出结果：
当前 Spring 应用上下文的类：org.springframework.context.annotation.AnnotationConfigApplicationContext
配置 Spring Boot 源
SpringAppliation 类型推断
当不加以设置 Web 类型，那么它采用推断：
-> SpringAppliation() -> deduceWebApplicationType() 第一次推断为 WebApplicationType.SERVLET
WebApplicationType.NONE : 非 Web 类型
Servlet 不存在Spring Web 应用上下文 ConfigurableWebApplicationContext 不存在
spring-boot-starter-web 不存在
spring-boot-starter-webflux 不存在
WebApplicationType.REACTIVE : Spring WebFlux
DispatcherHandler
spring-boot-starter-webflux 存在
Servlet 不存在
spring-boot-starter-web 不存在
WebApplicationType.SERVLET : Spring MVC
spring-boot-starter-web 存在
人工干预 Web 类型
设置 webApplicationType 属性 为 WebApplicationType.NONE
Spring Boot 事件
Spring 事件
Spring 内部发送事件
ContextRefreshedEvent
ApplicationContextEventApplicationEvent
refresh() -> finishRefresh() -> publishEvent(new ContextRefreshedEvent(this));
ContextClosedEvent
ApplicationContextEventApplicationEvent
close() -> doClose() -> publishEvent(new ContextClosedEvent(this));
自定义事件
PayloadApplicationEvent
Spring 事件 都是 ApplicationEvent 类型
发送 Spring 事件通过 ApplicationEventMulticaster#multicastEvent(ApplicationEvent, ResolvableType)
Spring 事件的类型 ApplicationEvent
Spring 事件监听器 ApplicationListener
Spring 事件广播器 ApplicationEventMulticaster
实现类：SimpleApplicationEventMulticaster
Spring 事件理解为消息
ApplicationEvent 相当于消息内容
ApplicationListener 相当于消息消费者、订阅者
ApplicationEventMulticaster 相当于消息生产者、发布者
Spring Boot 事件监听示例
@EnableAutoConfigurationpublic class SpringBootEventDemo {
public static void main(String[] args) { new SpringApplicationBuilder(SpringBootEventDemo.class) .listeners(event -> { // 增加监听器 System.err.println("监听到事件 ： " + event.getClass().getSimpleName()); }) .run(args) .close(); ; // 运行}}
ApplicationStartingEvent（1）ApplicationEnvironmentPreparedEvent（2）ApplicationPreparedEvent（3）ContextRefreshedEventServletWebServerInitializedEventApplicationStartedEvent（4）ApplicationReadyEvent（5）ContextClosedEventApplicationFailedEvent (特殊情况)（6）
Spring Boot 事件监听器
org.springframework.context.ApplicationListener=\org.springframework.boot.ClearCachesApplicationListener,\org.springframework.boot.builder.ParentContextCloserApplicationListener,\org.springframework.boot.context.FileEncodingApplicationListener,\org.springframework.boot.context.config.AnsiOutputApplicationListener,\org.springframework.boot.context.config.ConfigFileApplicationListener,\org.springframework.boot.context.config.DelegatingApplicationListener,\org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\org.springframework.boot.context.logging.LoggingApplicationListener,\org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListenerConfigFileApplicationListener 监听 ApplicationEnvironmentPreparedEvent 事件从而加载 application.properties 或者 application.yml 文件
Spring Boot 很多组件依赖于 Spring Boot 事件监听器实现，本质是 Spring Framework 事件/监听机制
SpringApplication 利用
Spring 应用上下文（ApplicationContext）生命周期控制 注解驱动 Bean Spring 事件/监听（ApplicationEventMulticaster）机制加载或者初始化组件