springboot Web开发

1.web开发

使用springboot

1. 创建SpringBoot应用，选中我们需要的模块
2. SpringBoot已经默认将这些场景配置好了，只需要在配置文件中指定少量配置
3. 自己编写业务代码

自动配置原理？
这个场景springboot我们配置了什么？能不能修改？能修改哪些配置？能不能扩展？

      xxxxAutoConfiguration  : 帮我们给容器中自动配置组件
      xxxProperties:配置类来封装配置文件的内容

2.springboot对静态资源的映射规则

@ConfigurationProperties(
    prefix = "spring.resources",
    ignoreUnknownFields = false
)
public class ResourceProperties {
// 设置和资源有关的参数

  public void addResourceHandlers(ResourceHandlerRegistry registry) {
            if (!this.resourceProperties.isAddMappings()) {
                logger.debug("Default resource handling disabled");
            } else {
                Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
                CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
                if (!registry.hasMappingForPattern("/webjars/**")) {
                    this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
                }

                String staticPathPattern = this.mvcProperties.getStaticPathPattern();
                if (!registry.hasMappingForPattern(staticPathPattern)) {
                    this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
                }

            }
        }
        //配置欢迎页的映射
      @Bean
		public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext) {
			return new WelcomePageHandlerMapping(new TemplateAvailabilityProviders(applicationContext),
					applicationContext, getWelcomePage(), this.mvcProperties.getStaticPathPattern());
		}

　　　@Configuration
		@ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
		public static class FaviconConfiguration implements ResourceLoaderAware {

			private final ResourceProperties resourceProperties;

			private ResourceLoader resourceLoader;

			public FaviconConfiguration(ResourceProperties resourceProperties) {
				this.resourceProperties = resourceProperties;
			}

			@Override
			public void setResourceLoader(ResourceLoader resourceLoader) {
				this.resourceLoader = resourceLoader;
			}

			@Bean
			public SimpleUrlHandlerMapping faviconHandlerMapping() {
				SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
				mapping.setOrder(Ordered.HIGHEST_PRECEDENCE + 1);

				mapping.setUrlMap(Collections.singletonMap("**/favicon.ico", faviconRequestHandler()));
				return mapping;
			}

			@Bean
			public ResourceHttpRequestHandler faviconRequestHandler() {
				ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
				requestHandler.setLocations(resolveFaviconLocations());
				return requestHandler;
			}

			private List<Resource> resolveFaviconLocations() {
				String[] staticLocations = getResourceLocations(this.resourceProperties.getStaticLocations());
				List<Resource> locations = new ArrayList<>(staticLocations.length + 1);
				Arrays.stream(staticLocations).map(this.resourceLoader::getResource).forEach(locations::add);
				locations.add(new ClassPathResource("/"));
				return Collections.unmodifiableList(locations);
			}

		}

	}

1. 所有/webjars/** , 都去classpath:/META-INF/resources/webjars/　　找资源
   　　webjars: 以jar包的方式引入静态资源
   　　https://www.webjars.org/
   
   localhost:8080/webjars/jquery/3.4.1/jquery.js

<!--引入jquery  在访问的时候只需要写webjars下面的资源名称即可-->
        <dependency>
            <groupId>org.webjars</groupId>
            <artifactId>jquery</artifactId>
            <version>3.4.1</version>
        </dependency>

2. ＂/**＂访问当前项目的任何资源，（静态资源文件夹）

   classpath:/META-INF/resources/"
   "classpath:/resources/"
   "classpath:/static/"
   "classpath:/public/"
   /: 当前项目的根路径

localhost:8080/abc　　＝＝＝去静态资源里面寻找abc

3.　 欢迎页：静态资源文件夹下的所有index.html页面；被/**映射
　　localhost:8080/ 找index页面
4. 所有的 **/favicon.ico都是在静态资源文件下找