【小家Spring】Spring注解驱动开发---Servlet 3.0整合Spring MVC（不使用web.xml部署描述符，使用ServletContainerInitializer）（中）

@HandlesTypes(WebApplicationInitializer.class)
public class SpringServletContainerInitializer implements ServletContainerInitializer {
  @Override
  public void onStartup(@Nullable Set<Class<?>> webAppInitializerClasses, ServletContext servletContext)
      throws ServletException {
    List<WebApplicationInitializer> initializers = new LinkedList<>();
    if (webAppInitializerClasses != null) {
      for (Class<?> waiClass : webAppInitializerClasses) {
        // Be defensive: Some servlet containers provide us with invalid classes,
        // no matter what @HandlesTypes says...
        if (!waiClass.isInterface() && !Modifier.isAbstract(waiClass.getModifiers()) &&
            WebApplicationInitializer.class.isAssignableFrom(waiClass)) {
          try {
            initializers.add((WebApplicationInitializer)
                ReflectionUtils.accessibleConstructor(waiClass).newInstance());
          }
          catch (Throwable ex) {
            throw new ServletException("Failed to instantiate WebApplicationInitializer class", ex);
          }
        }
      }
    }
    if (initializers.isEmpty()) {
      servletContext.log("No Spring WebApplicationInitializer types detected on classpath");
      return;
    }
    servletContext.log(initializers.size() + " Spring WebApplicationInitializers detected on classpath");
    AnnotationAwareOrderComparator.sort(initializers);
    for (WebApplicationInitializer initializer : initializers) {
      initializer.onStartup(servletContext);
    }
  }
}

// 备注：此处@ControllerAdvice、RestControllerAdvice 这个注解不要忘了，属于Controller层处理全局异常的，应该交给web去扫描
@ComponentScan(value = "com.fsx", excludeFilters = {
        @Filter(type = FilterType.ANNOTATION, classes = {Controller.class, ControllerAdvice.class, RestControllerAdvice.class})
})
@Configuration //最好标注上，本人亲测若不标准，可能扫描不生效
public class RootConfig {
}
// 此处记得排除掉@Controller和@ControllerAdvice、@RestControllerAdvice
@ComponentScan(value = "com.fsx", useDefaultFilters = false,
        includeFilters = {@Filter(type = FilterType.ANNOTATION, classes = {Controller.class, ControllerAdvice.class, RestControllerAdvice.class})}
)
@Configuration //最好标注上，本人亲测若不标准，可能扫描不生效
public class AppConfig {
}

/**
 * 自己实现 基于注解驱动的ServletInitializer来初始化DispatcherServlet
 */
public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    /**
     * 根容器的配置类；（Spring的配置文件）   父容器；
     */
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[]{RootConfig.class};
    }
    /**
     * web容器的配置类（SpringMVC配置文件）  子容器；
     */
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[]{AppConfig.class};
    }
    //获取DispatcherServlet的映射信息
    // 注意： /：拦截所有请求（包括静态资源（xx.js,xx.png）），但是不包括*.jsp；
    //  /*：拦截所有请求；连*.jsp页面都拦截；jsp页面是tomcat的jsp引擎解析的；
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
    // 若你想定制化父类的一些默认行为  这里都是可以复写父类的protected方法的~~~~
    // Spring MVC也推荐你这么干~
    @Override
    protected FrameworkServlet createDispatcherServlet(WebApplicationContext servletAppContext) {
        DispatcherServlet dispatcherServlet = (DispatcherServlet) super.createDispatcherServlet(servletAppContext);
        // dispatcherServlet.setDetectAllHandlerAdapters(false); 
        return dispatcherServlet;
    }
}

@Controller
public class HelloController {
    @Autowired
    HelloService helloService;
    @ResponseBody
    @RequestMapping("/hello")
    public String hello() {
        System.out.println(helloService); //com.fsx.service.HelloServiceImpl@512663b0
        return "hello...";
    }
}

@ComponentScan(value = "com.fsx", excludeFilters = {
        @Filter(type = FilterType.ANNOTATION, classes = {Controller.class}),
        //排除掉web容器的配置文件，否则会重复扫描
        @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = {AppConfig.class})
})
@Configuration
public class RootConfig {
}

//web子容器里注册一个Child
public class AppConfig {
    @Bean
    public Child child() {
        return new Child();
    }
}
//父容器里注册一个Parent
public class RootConfig {
    @Bean
    public Parent parent() {
        return new Parent();
    }
}

@EnableWebMvc
@Configuration //一定要说明这个文件是个配置文件
public class WebMvcConfig implements WebMvcConfigurer {
    //视图解析器
    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        //默认所有的页面都从 /WEB-INF/ xxx .jsp
        //registry.jsp();
        registry.jsp("/WEB-INF/views/", ".jsp");
    }
    // 开启静态资源的请求转发到默认servlet上,不配置页面报错404,(默认servlet不是DispatcherServlet!理解的)
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
    //自定义添加拦截器=========这个比较常用
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //registry.addInterceptor(new MyFirstInterceptor()).addPathPatterns("/**");
    }
}

    //自定义一个视图解析器
    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("WEB-INF/views/");
        resolver.setSuffix(".html");
        resolver.setExposeContextBeansAsAttributes(true);
        return resolver;
    }