SpringBoot之旅-启动原理及自定义starter

public static ConfigurableApplicationContext run(Class<?>[] primarySources,String[] args) {return new SpringApplication(primarySources).run(args);}

public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {this.resourceLoader = resourceLoader;    Assert.notNull(primarySources, "PrimarySources must not be null");//保存主配置类 this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));//确定web应用类型this.webApplicationType = WebApplicationType.deduceFromClasspath();//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.main

public ConfigurableApplicationContext run(String... args) {   StopWatch stopWatch = new StopWatch();   stopWatch.start();   ConfigurableApplicationContext context = null;   Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();   configureHeadlessProperty();//从类路径下META-INF/spring.factories获取SpringApplicationRunListeners   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      configureIgnoreBeanInfo(environment);//打印Banner图      Banner printedBanner = printBanner(environment);//创建ApplicationContext,决定创建web的ioc还是普通的ioc        context = createApplicationContext();//异常分析报告      exceptionReporters = getSpringFactoriesInstances(            SpringBootExceptionReporter.class,new Class[] { ConfigurableApplicationContext.class }, context);//准备上下文环境，将environment保存到ioc中//applyInitializers()：回调之前保存的所有的ApplicationContextInitializer的initialize方法 //listeners.contextPrepared(context) //prepareContext运行完成以后回调所有的SpringApplicationRunListener的contextLoaded（）      prepareContext(context, environment, listeners, applicationArguments,            printedBanner);//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）//扫描，创建，加载所有组件的地方,（配置类，组件，自动配置）      refreshContext(context);             afterRefresh(context, applicationArguments);      stopWatch.stop();if (this.logStartupInfo) {new StartupInfoLogger(this.mainApplicationClass)               .logStarted(getApplicationLog(), stopWatch);      }//所有的SpringApplicationRunListener回调started方法      listeners.started(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      callRunners(context, applicationArguments);   }catch (Throwable ex) {      handleRunFailure(context, ex, exceptionReporters, listeners);throw new IllegalStateException(ex);   }
try {//所有的SpringApplicationRunListener回调running方法      listeners.running(context);   }catch (Throwable ex) {      handleRunFailure(context, ex, exceptionReporters, null);throw new IllegalStateException(ex);   }//整个SpringBoot应用启动完成以后返回启动的ioc容器return context;}

<dependencies><!--引入自动配置模块--><dependency><groupId>com.yuanqinnan-starter</groupId><artifactId>yuanqinnan-springboot-starter-autoconfigurer</artifactId><version>0.0.1-SNAPSHOT</version></dependency></dependencies>

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.1.4.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.yuanqinnan-starter</groupId><artifactId>yuanqinnan-springboot-starter-autoconfigurer</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><properties><java.version>1.8</java.version></properties>
<dependencies><!--引入spring-boot-starter；所有starter的基本配置--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency></dependencies></project>

@ConfigurationProperties(prefix = "yuanqinnan.hello")public class HelloProperties {//前缀private String prefix;//后缀private String suffix;
public String getPrefix() {return prefix;    }
public void setPrefix(String prefix) {this.prefix = prefix;    }
public String getSuffix() {return suffix;    }
public void setSuffix(String suffix) {this.suffix = suffix;    }}

public class HelloService {
    HelloProperties helloProperties;
public HelloProperties getHelloProperties() {return helloProperties;    }
public void setHelloProperties(HelloProperties helloProperties) {this.helloProperties = helloProperties;    }
public String sayHello(String name) {return helloProperties.getPrefix() + "-" + name + helloProperties.getSuffix();    }}

@Configuration@ConditionalOnWebApplication //web应用才生效@EnableConfigurationProperties(HelloProperties.class)public class HelloServiceAutoConfiguration {
@Autowired    HelloProperties helloProperties;@Beanpublic HelloService helloService(){        HelloService service = new HelloService();        service.setHelloProperties(helloProperties);return service;    }}

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\  com.yuanqinnan.starter.HelloServiceAutoConfiguration

<!--引入自定义starter--><dependency><groupId>com.yuanqinnan.starter</groupId><artifactId>yuanqinnan-springboot-starter</artifactId><version>1.0-SNAPSHOT</version></dependency>

yuanqinnan.hello.prefix=早安yuanqinnan.hello.suffix=晚安

@AutowiredHelloService helloService;
@Testpublic void contextLoads() {System.out.println(helloService.sayHello("世界"));}