public class WebInit implements WebApplicationInitializer {

    @Override

    public void onStartup(ServletContext container) throws ServletException {

        //项目启动则执行 :

        //前端控制器

        //对比xml配置,配置在web.xml中的

        /*

         * <servlet>

         *      <servlet-name>dispatcherServlet</servlet-name>

         *      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

         *      <init-param>

         *          <param-name>contextConfigLocation</param-name>

         *          <param-value>/WEB-INF/classes/application.xml</param-value>

         *      </init-param>

         *      <load-on-startup>1</load-on-startup>

         * </servlet>

         * <servlet-mapping>

         *      <servlet-name>dispatherServlet</servlet-name>

         *      <url-pattern>*.do</url-pattern>

         * </servlet-mapping>

         * */

        //javaConfig配置

        //这句相当于控制器核心类

        ServletRegistration.Dynamic dispatcherServletRegistration = container.addServlet("dispatcher", new DispatcherServlet());

        //这句相当于配置服务器启动就加载servlet容器

        dispatcherServletRegistration.setLoadOnStartup(1);

        //这句相当于配置注解驱动

        dispatcherServletRegistration.setInitParameter("contextClass", "org.springframework.web.context.support.AnnotationConfigWebApplicationContext");

        //这句相当于加载springmvc核心配置文件

        dispatcherServletRegistration.setInitParameter("contextConfigLocation", "com.mike.small.config.SpringMvcConfig");

        //拦截所有url

        dispatcherServletRegistration.addMapping("/");

        //处理乱码过滤器

        CharacterEncodingFilter filter = new CharacterEncodingFilter();

        filter.setEncoding("UTF-8");

        FilterRegistration.Dynamic characterEncodingFilterRegistration = container.addFilter("characterEncodingFilter", filter);

        characterEncodingFilterRegistration.addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST, DispatcherType.FORWARD), false, "/*");

        //注解驱动类

        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();

        rootContext.register(SpringMvcConfig.class);

        //这句相当于web.xml的监听器

        /*<listener>

            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

          </listener>

         */

        container.addListener(new ContextLoaderListener(rootContext));

    }

}

@Configuration // this class contains bean definitions

@EnableWebMvc // same as <mvc:annotation-driven />

@ComponentScan(basePackages = {"com.mike.small"})

public class SpringMvcConfig extends WebMvcConfigurerAdapter {

    @Override

    public void addResourceHandlers(ResourceHandlerRegistry registry) {

        // declare static resources

        registry.addResourceHandler("/static/**").addResourceLocations("/static/");

    }

    @Bean

    public InternalResourceViewResolver viewResolver() {

        // view resolver

        InternalResourceViewResolver resolver = new InternalResourceViewResolver();

        resolver.setPrefix("/WEB-INF/jsp/");

        resolver.setSuffix(".jsp");

        return resolver;

    }

    @Bean

    public CommonsMultipartResolver multipartResolver() {

        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();

        multipartResolver.setMaxUploadSize(104857600);

        return multipartResolver;

    }

}