第11章：SpringMVC注解配置

一、注解配置SpringMVC

目的是：使用配置类和注解代替web.xml和Spring.MVC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。

①创建一个Module，配置好pom.xml

②创建webapp和WEB-INF文件夹

③创建一个配置类

2.创建WebInit类代替web.xml，继承AbstractAnnotationConfigDispatcherServletInitializer

①WebInit

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};
   }
}

 ②创建SpringConfig 和 WebConfig配置类

@Configuration
public class SpringConfig {
}

@Configuration
public class WebConfig {
}

3. WebConfig代替SpringMVC配置文件

• 扫描组件、视图解析器、view-controller、default-servlet-handler
• Mvc注解驱动、文件上传解析器、异常处理、拦截器

配置模板

//当前类标识一个配置类
@Configuration
// 开启扫描组件
@ComponentScan ("com.wzl.mvc.controller")
//开启MVC注解驱动
@EnableWebMvc
public class WebConfig {


   //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;
   }
}

②TestController控制器

 //访问主页

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

4.配置其他的，实现其他的配置。

实现接口implements WebMvcConfigurer

public class WebConfig implements WebMvcConfigurer{
}

配置默认servlet可用，default-servlet-handler

Ctrl+o 找到

@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
   configurer.enable();
}

配置拦截器

①创建拦截器

public class TestInterceptor implements HandlerInterceptor {
   @Override
   public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
      System.out.println("preHandle");
      return true;
   }

   @Override
   public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
   }

   @Override
   public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
   }
}

 ②在WebConfig

@Override
public void addInterceptors(InterceptorRegistry registry) {
   TestInterceptor testInterceptor = new TestInterceptor();
   // 添加拦截路径
   registry.addInterceptor(testInterceptor).addPathPatterns("/admin/**");
}

 ③在控制器添加

@RequestMapping("/admin/index")
public String index1(){
   return "index";
}

 ④测试

配置view-controller

@Override
public void addViewControllers(ViewControllerRegistry registry) {
   registry.addViewController("/").setViewName("index");
}

 跳转到主页面

 

配置文件上传

//文件上传解析器
@Bean
public MultipartResolver multipartResolver(){
   CommonsMultipartResolver commonsMultipartResolver = new CommonsMultipartResolver();
   return commonsMultipartResolver;
}

配置异常解析器

@Override
public void configureHandlerExceptionResolvers(List resolvers) {
   SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
   Properties properties = new Properties();
   properties.setProperty("java.lang.ArithmeticException","error");
   //设置异常映射
   exceptionResolver.setExceptionMappings(properties);
   exceptionResolver.setExceptionAttribute("ex");
   resolvers.add(exceptionResolver);
}