【springmvc】12.注解配置springmvc

柔光的暖阳◎ 2024-03-26 20:13 87阅读 0赞

## 通过注解配置springmvc ##

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
         */
        @Override
        protected Class<?>[] getRootConfigClasses() {
        
            return new Class[]{
        SpringConfig.class};
        }
    
        /**
         * 指定SpringMVC的配置类
         * @return
         */
        @Override
        protected Class<?>[] getServletConfigClasses() {
        
            return new Class[]{
        WebConfig.class};
        }
    
        /**
         * 指定DispatcherServlet的映射规则，即url-pattern
         * @return
         */
        @Override
        protected String[] getServletMappings() {
        
            return new String[]{
        "/"};
        }
    
        /**
         * 添加过滤器
         * @return
         */
        @Override
        protected 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
        @Override
        public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        
            configurer.enable();
        }
    
        //配置文件上传解析器
        @Bean
        public CommonsMultipartResolver multipartResolver(){
        
            return new CommonsMultipartResolver();
        }
    
        //配置拦截器
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
        
            FirstInterceptor firstInterceptor = new FirstInterceptor();
            registry.addInterceptor(firstInterceptor).addPathPatterns("/**");
        }
        
        //配置视图控制
        
        /*@Override
        public void addViewControllers(ViewControllerRegistry registry) {
            registry.addViewController("/").setViewName("index");
        }*/
        
        //配置异常映射
        /*@Override
        public 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
        @Bean
        public 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
        @Bean
        public 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
        @Bean
        public 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";
    }