说说springboot启动机制 ----- maven对依赖的管理，场景器，SpringBootApplication，EnableAutoConfiguration几个注解，加载了Tomcat，Mvc ...
说说springboot启动机制
https://ke.qq.com/webcourse/index.html#cid=333216&term_id=100395479&taid=2568313133929888&vid=5285890788262993749
通过@EnableAutoConfiguration 加载
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration --->
@ComponentScan(
excludeFilters={@Filter(
type=FilterType.CUSTOM,
classes= {TypeExcludeFilter.class}
), @Filter(
type=FilterType.CUSTOM,
classes= {AutoConfigurationExcludeFilter.class}
)}
)public @interfaceSpringBootApplication {
@AliasFor(
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import({EnableAutoConfigurationImportSelector.class}) //------>通过public @interfaceEnableAutoConfiguration {
String ENABLED_OVERRIDE_PROPERTY= "spring.boot.enableautoconfiguration";
Class<?>[] exclude() default{};
String[] excludeName()default{};
}
@Import 把一个类通过这种方式交给Spring容器管理
@Import({EnableAutoConfigurationImportSelector.class}) 点进去看这个类，再看它的父类
@Deprecated
public class EnableAutoConfigurationImportSelector extends AutoConfigurationImportSelector {
protected List<String>getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
List<String> configurations = SpringFactoriesLoader.loadFactoryNames(this.getSpringFactoriesLoaderFactoryClass(), this.getBeanClassLoader());
Assert.notEmpty(configurations,"No auto configuration classes foundin META-INF/spring.factories. If you are using a custom packaging, make sure that file is correct.");returnconfigurations;
}
看出它回到这个包的路径下读取这个
spring.factories
配置文件：重点看这个三个
org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration这个文件中，有启动Tomcat
老师的版本是2.0
本人这个org.springframework.boot.autoconfigure 的jar包是1.5.10... 启动tomcat如下代码
WebMvcAutoConfiguration.java 文件中：主要通过enablewebmvc注解 把springmvc加载进来
手写spirngboot ,启动验证
