1 SpringMVC自动配置概览

Spring Boot provides auto-configuration for Spring MVC that works well with most applications.(大多场景我们都无需自定义配置)

The auto-configuration adds the following features on top of Spring’s defaults:

Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.
- 内容协商视图解析器和BeanName视图解析器
Support for serving static resources, including support for WebJars (covered later in this document)).
- 静态资源（包括webjars）
Automatic registration of Converter, GenericConverter, and Formatter beans.
- 自动注册 Converter，GenericConverter，Formatter
Support for HttpMessageConverters (covered later in this document).
- 支持 HttpMessageConverters （后来我们配合内容协商理解原理）
Automatic registration of MessageCodesResolver (covered later in this document).
- 自动注册 MessageCodesResolver （国际化用）
Static index.html support.
- 静态index.html 页支持
Custom Favicon support (covered later in this document).
- 自定义 Favicon
Automatic use of a ConfigurableWebBindingInitializer bean (covered later in this document).
- 自动使用 ConfigurableWebBindingInitializer ，（DataBinder负责将请求数据绑定到JavaBean上）

If you want to keep those Spring Boot MVC customizations and make more MVC customizations (interceptors, formatters, view controllers, and other features), you can add your own @Configuration class of type WebMvcConfigurer but without @EnableWebMvc.

不用@EnableWebMvc注解。使用 @Configuration + WebMvcConfigurer 自定义规则

If you want to provide custom instances of RequestMappingHandlerMapping, RequestMappingHandlerAdapter, or ExceptionHandlerExceptionResolver, and still keep the Spring Boot MVC customizations, you can declare a bean of type WebMvcRegistrations and use it to provide custom instances of those components.

声明 WebMvcRegistrations 改变默认底层组件

If you want to take complete control of Spring MVC, you can add your own @Configuration annotated with @EnableWebMvc, or alternatively add your own @Configuration-annotated DelegatingWebMvcConfiguration as described in the Javadoc of @EnableWebMvc.

使用 @EnableWebMvc+@Configuration+DelegatingWebMvcConfiguration 全面接管SpringMVC

2 简单功能分析

2.1 静态资源访问

2.1.1 静态资源目录

只要静态资源放在类路径下： called /static (or /public or /resources or /META-INF/resources

访问：当前项目根路径/ + 静态资源名
原理： 静态映射/**。

请求进来，先去找Controller看能不能处理。不能处理的所有请求又都交给静态资源处理器。静态资源也找不到则响应404页面。

改变默认的静态资源路径

spring:
  web:
    resources:
      static-locations: classpath:/abc

2.1.2 静态资源访问前缀

（默认无前缀）

spring:
  mvc:
    static-path-pattern: /res/**

当前项目 + static-path-pattern + 静态资源名 = 静态资源文件夹下找

2.1.3 webjar

自动映射 /webjars/**

webjars官方网站

		<dependency>
            <groupId>org.webjars.npm</groupId>
            <artifactId>jquery</artifactId>
            <version>3.6.0</version>
        </dependency>

访问地址：http://localhost:8080/webjars/jquery/3.6.0/dist/jquery.js 后面地址要按照依赖里面的包路径

2.2 欢迎页支持

静态资源路径下 index.html

可以配置静态资源路径

但是不可以配置静态资源的访问前缀。否则导致 index.html不能被默认访问

spring:
#  mvc:
#    static-path-pattern: /res/**   这个会导致welcome page功能失效

  web:
    resources:
      static-locations: classpath:/abc

controller能处理/index

2.3 自定义 `Favicon`

favicon.ico 放在静态资源目录下即可。（出不来图标的话，把浏览器缓存清了或者关闭浏览器重新打开，即可）

spring:
#  mvc:
#    static-path-pattern: /res/**   这个会导致 Favicon 功能失效

2.4 静态资源配置原理

SpringBoot启动默认加载 xxxAutoConfiguration 类（自动配置类）

SpringMVC功能的自动配置类 WebMvcAutoConfiguration，生效

@Configuration(
    proxyBeanMethods = false
)
@ConditionalOnWebApplication(
    type = Type.SERVLET
)
@ConditionalOnClass({
      
      Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class})
@ConditionalOnMissingBean({
      
      WebMvcConfigurationSupport.class})
@AutoConfigureOrder(-2147483638)
@AutoConfigureAfter({
      
      DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class})
public class WebMvcAutoConfiguration {
      
      }

给容器中配了什么。

  @Configuration(
        proxyBeanMethods = false
    )
    @Import({
      
      WebMvcAutoConfiguration.EnableWebMvcConfiguration.class})
        @EnableConfigurationProperties({
      
      WebMvcProperties.class, WebProperties.class})
    @Order(0)
    public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer, ServletContextAware {
      
      }

配置文件的相关属性和 xxx 进行了绑定。WebMvcProperties==spring.mvc、WebProperties==spring.web

2.4.1 配置类只有一个有参构造器

	//有参构造器所有参数的值都会从容器中确定
//WebProperties webProperties；获取和spring.web绑定的所有的值的对象
//WebMvcProperties mvcProperties 获取和spring.mvc绑定的所有的值的对象
//ListableBeanFactory beanFactory Spring的beanFactory
//HttpMessageConverters 找到所有的HttpMessageConverters
//ResourceHandlerRegistrationCustomizer 找到 资源处理器的自定义器。=========
//DispatcherServletPath  
//ServletRegistrationBean   给应用注册Servlet、Filter....
	 public WebMvcAutoConfigurationAdapter(WebProperties webProperties, WebMvcProperties mvcProperties, ListableBeanFactory beanFactory, ObjectProvider<HttpMessageConverters> messageConvertersProvider, ObjectProvider<WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider, ObjectProvider<DispatcherServletPath> dispatcherServletPath, ObjectProvider<ServletRegistrationBean<?>> servletRegistrations) {
    
    
            this.resourceProperties = webProperties.getResources();
            this.mvcProperties = mvcProperties;
            this.beanFactory = beanFactory;
            this.messageConvertersProvider = messageConvertersProvider;
            this.resourceHandlerRegistrationCustomizer = (WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer)resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
            this.dispatcherServletPath = dispatcherServletPath;
            this.servletRegistrations = servletRegistrations;
            this.mvcProperties.checkConfiguration();
        }

2.4.2 资源处理的默认规则

这个是访问静态资源的默认配置规则，引入了jQuery这个静态资源之后，/webjars/**这个前缀已经默认配置好了，同时也添加了/META-INF/resources/webjars/这个静态资源访问路径

 public void addResourceHandlers(ResourceHandlerRegistry registry) {
    
    
            if (!this.resourceProperties.isAddMappings()) {
    
    
                logger.debug("Default resource handling disabled");
            } else {
    
    
                this.addResourceHandler(registry, "/webjars/**", "classpath:/META-INF/resources/webjars/");
                this.addResourceHandler(registry, this.mvcProperties.getStaticPathPattern(), (registration) -> {
    
    
                    registration.addResourceLocations(this.resourceProperties.getStaticLocations());
                    if (this.servletContext != null) {
    
    
                        ServletContextResource resource = new ServletContextResource(this.servletContext, "/");
                        registration.addResourceLocations(new Resource[]{
    
    resource});
                    }

                });
            }
        }

        private void addResourceHandler(ResourceHandlerRegistry registry, String pattern, String... locations) {
    
    
            this.addResourceHandler(registry, pattern, (registration) -> {
    
    
                registration.addResourceLocations(locations);
            });
        }

        private void addResourceHandler(ResourceHandlerRegistry registry, String pattern, Consumer<ResourceHandlerRegistration> customizer) {
    
    
            if (!registry.hasMappingForPattern(pattern)) {
    
    
                ResourceHandlerRegistration registration = registry.addResourceHandler(new String[]{
    
    pattern});
                customizer.accept(registration);
                registration.setCachePeriod(this.getSeconds(this.resourceProperties.getCache().getPeriod()));
                registration.setCacheControl(this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl());
                registration.setUseLastModified(this.resourceProperties.getCache().isUseLastModified());
                this.customizeResourceHandlerRegistration(registration);
            }
        }

spring:
#  mvc:
#    static-path-pattern: /res/**

  resources:
    static-locations: classpath:/abc
    add-mappings: false   #禁用所有静态资源规则

@ConfigurationProperties("spring.web")
public class WebProperties {
    
    
    private Locale locale;
    private WebProperties.LocaleResolver localeResolver;
    private final WebProperties.Resources resources;

    public WebProperties() {
    
    
        this.localeResolver = WebProperties.LocaleResolver.ACCEPT_HEADER;
        this.resources = new WebProperties.Resources();
    }

    public Locale getLocale() {
    
    
        return this.locale;
    }

    public void setLocale(Locale locale) {
    
    
        this.locale = locale;
    }

    public WebProperties.LocaleResolver getLocaleResolver() {
    
    
        return this.localeResolver;
    }

    public void setLocaleResolver(WebProperties.LocaleResolver localeResolver) {
    
    
        this.localeResolver = localeResolver;
    }

    public WebProperties.Resources getResources() {
    
    
        return this.resources;
    }

    public static class Resources {
    
    
        private static final String[] CLASSPATH_RESOURCE_LOCATIONS = new String[]{
    
    "classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/"};
        private String[] staticLocations;
        private boolean addMappings;
        private boolean customized;
        private final WebProperties.Resources.Chain chain;
        private final WebProperties.Resources.Cache cache;

        public Resources() {
    
    
            this.staticLocations = CLASSPATH_RESOURCE_LOCATIONS;
            this.addMappings = true;
            this.customized = false;
            this.chain = new WebProperties.Resources.Chain();
            this.cache = new WebProperties.Resources.Cache();
        }

2.4.3 欢迎页的处理规则

// HandlerMapping：处理器映射。保存了每一个Handler能处理哪些请求。	

	  @Bean
        public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext, FormattingConversionService mvcConversionService, ResourceUrlProvider mvcResourceUrlProvider) {
    
    
            WelcomePageHandlerMapping welcomePageHandlerMapping = new WelcomePageHandlerMapping(new TemplateAvailabilityProviders(applicationContext), applicationContext, this.getWelcomePage(), this.mvcProperties.getStaticPathPattern());
            welcomePageHandlerMapping.setInterceptors(this.getInterceptors(mvcConversionService, mvcResourceUrlProvider));
            welcomePageHandlerMapping.setCorsConfigurations(this.getCorsConfigurations());
            return welcomePageHandlerMapping;
        }

WelcomePageHandlerMapping(TemplateAvailabilityProviders templateAvailabilityProviders, ApplicationContext applicationContext, Resource welcomePage, String staticPathPattern) {
    
    
        if (welcomePage != null && "/**".equals(staticPathPattern)) {
    
    
            //要用欢迎页功能，必须是/**
            logger.info("Adding welcome page: " + welcomePage);
            this.setRootViewName("forward:index.html");
        } else if (this.welcomeTemplateExists(templateAvailabilityProviders, applicationContext)) {
    
    
            //调用Controller  /index
            logger.info("Adding welcome page template: index");
            this.setRootViewName("index");
        }
    }

2.4.4 favicon

浏览器会发送 /favicon 请求获取到图标，整个session期间不再获取

04-web开发之简单功能分析

1 SpringMVC自动配置概览

2 简单功能分析

2.1 静态资源访问

2.1.1 静态资源目录

2.1.2 静态资源访问前缀

2.1.3 webjar

2.2 欢迎页支持

2.3 自定义 `Favicon`

2.4 静态资源配置原理

2.4.1 配置类只有一个有参构造器

2.4.2 资源处理的默认规则

2.4.3 欢迎页的处理规则

2.4.4 favicon

猜你喜欢

04-web开发之简单功能分析

1 SpringMVC自动配置概览

2 简单功能分析

2.1 静态资源访问

2.1.1 静态资源目录

2.1.2 静态资源访问前缀

2.1.3 webjar

2.2 欢迎页支持

2.3 自定义 Favicon

2.4 静态资源配置原理

2.4.1 配置类只有一个有参构造器

2.4.2 资源处理的默认规则

2.4.3 欢迎页的处理规则

2.4.4 favicon

猜你喜欢

2.3 自定义 `Favicon`