使用配置类和注解代替web.xml和SpringMVC配置文件的功能

1、创建初始化类，代替web.xml

在Servlet3.0环境中，容器会在类路径中查找实现javax.servlet.ServletContainerInitializer接口的类，如果找到的话就用它来配置Servlet容器。
Spring提供了这个接口的实现，名为SpringServletContainerInitializer，这个类反过来又会查找实现WebApplicationInitializer的类并将配置的任务交给它们来完成。Spring3.2引入了一个便利的WebApplicationInitializer基础实现，名为AbstractAnnotationConfigDispatcherServletInitializer，当我们的类扩展了AbstractAnnotationConfigDispatcherServletInitializer并将其部署到Servlet3.0容器的时候，容器会自动发现它，并用它来配置Servlet上下文。

public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {/*** 指定spring的配置类* @return*/@Overrideprotected Class<?>[] getRootConfigClasses() {return new Class[]{SpringConfig.class};}/*** 指定SpringMVC的配置类* @return*/@Overrideprotected Class<?>[] getServletConfigClasses() {return new Class[]{WebConfig.class};}/*** 指定DispatcherServlet的映射规则，即url-pattern* @return*/@Overrideprotected String[] getServletMappings() {return new String[]{"/"};}/*** 添加过滤器* @return*/@Overrideprotected Filter[] getServletFilters() {CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();encodingFilter.setEncoding("UTF-8");encodingFilter.setForceRequestEncoding(true);HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();return new Filter[]{encodingFilter, hiddenHttpMethodFilter};}
}

2、创建SpringConfig配置类，代替spring的配置文件

@Configuration
public class SpringConfig {//ssm整合之后，spring的配置信息写在此类中
}

3、创建WebConfig配置类，代替SpringMVC的配置文件

@Configuration
//扫描组件
@ComponentScan("com.atguigu.mvc.controller")
//开启MVC注解驱动
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {//使用默认的servlet处理静态资源@Overridepublic void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {configurer.enable();}//配置文件上传解析器@Beanpublic CommonsMultipartResolver multipartResolver(){return new CommonsMultipartResolver();}//配置拦截器@Overridepublic void addInterceptors(InterceptorRegistry registry) {FirstInterceptor firstInterceptor = new FirstInterceptor();registry.addInterceptor(firstInterceptor).addPathPatterns("/**");}//配置视图控制/*@Overridepublic void addViewControllers(ViewControllerRegistry registry) {registry.addViewController("/").setViewName("index");}*///配置异常映射/*@Overridepublic void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();Properties prop = new Properties();prop.setProperty("java.lang.ArithmeticException", "error");//设置异常映射exceptionResolver.setExceptionMappings(prop);//设置共享异常信息的键exceptionResolver.setExceptionAttribute("ex");resolvers.add(exceptionResolver);}*///配置生成模板解析器@Beanpublic ITemplateResolver templateResolver() {WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();// ServletContextTemplateResolver需要一个ServletContext作为构造参数，可通过WebApplicationContext 的方法获得ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(webApplicationContext.getServletContext());templateResolver.setPrefix("/WEB-INF/templates/");templateResolver.setSuffix(".html");templateResolver.setCharacterEncoding("UTF-8");templateResolver.setTemplateMode(TemplateMode.HTML);return templateResolver;}//生成模板引擎并为模板引擎注入模板解析器@Beanpublic SpringTemplateEngine templateEngine(ITemplateResolver templateResolver) {SpringTemplateEngine templateEngine = new SpringTemplateEngine();templateEngine.setTemplateResolver(templateResolver);return templateEngine;}//生成视图解析器并未解析器注入模板引擎@Beanpublic ViewResolver viewResolver(SpringTemplateEngine templateEngine) {ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();viewResolver.setCharacterEncoding("UTF-8");viewResolver.setTemplateEngine(templateEngine);return viewResolver;}}

4、测试功能

@RequestMapping("/")
public String index(){return "index";
}