通过注解方式配置SpringMVC

2022-01-06 0 By admin

使用配置类和注解方式代替web.xml和SpringMVC配置文件的功能。

一、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
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }
//指定SpringMVC的配置类
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }
//指定DispatcherServlet的映射规则,即url-pattern
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
//添加过滤器
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();
        encodingFilter.setEncoding("UTF-8");
        encodingFilter.setForceRequestEncoding(true);
        HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
        return new Filter[]{encodingFilter, hiddenHttpMethodFilter};
    }
}

二、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
}

三、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;
    }
}

四、测试功能

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