Spring MVC原理

http://localhost:8080/myapp/app/test
1.localhost:8080
通过8080端口找到tomcat
2./myapp
找到tomcat下myapp应用程序
3./app
①tomcat解析/webapp/WEB-INF/web.xml,
②实例化DispatcherServlet，
③初始化DispatcherServlet.init()并创建Spring容器XmlWebApplicationContext，将spring.xml配置到Spring容器中
④servlet-mapping为/app/*
4./test
遍历Spring容器下面的所有Controller bean对象，找到@GetMapping为/test的方法执行

    
        app
        org.springframework.web.servlet.DispatcherServlet
        
            contextConfigLocation
            
        
        1
    

    
        app
        /app/*
    

官网上有介绍，https://docs.spring.io/spring-framework/docs/current/reference/html/web.html
可以直接用java实现
public class MyWebApplicationInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext servletContext) {

        // Load Spring web application configuration
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.register(AppConfig.class);

        // Create and register the DispatcherServlet
        DispatcherServlet servlet = new DispatcherServlet(context);
        ServletRegistration.Dynamic registration = servletContext.addServlet("app", servlet);
        registration.setLoadOnStartup(1);
        registration.addMapping("/app/*");
    }
}