springboot对静态资源的映射规则

第一种映射规则：

WebMvcAutoConfiguration类中addResourceHandlers（添加资源映射）方法的部分源码：

		if (!registry.hasMappingForPattern("/webjars/**")) {
				customizeResourceHandlerRegistration(registry.addResourceHandler("/webjars/**")
						.addResourceLocations("classpath:/META-INF/resources/webjars/")
						.setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
			}

解释：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;
webjars官网链接：https://www.webjars.org/

在pom文件中引用webjars

导入包的目录结构：

在访问的时候只需要写webjars下面资源的名称即可：http://localhost:8080/webjars/jquery/3.4.1/jquery.js

这个类可以设置和静态资源有关的参数，缓存时间等

@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties {

第二种映射规则：

“/**” 访问当前项目的任何资源（静态资源的文件夹），默认从这些文件夹寻找；

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

列如：访问static→jquery→jquery-3.4.1.slim.js

访问：http://localhost:8080/jquery/jquery-3.4.1.slim.js；如图：

配置欢迎页面的映射

WebMvcAutoConfiguration类的welcomePageHandlerMapping（配置欢迎页面）方法：

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

欢迎页;静态资源文件夹下的所有index.htm页面;被"/**"映射;

列如：http://localhost:8080/，访问index界面；

设置图标映射

WebMvcAutoConfiguration类的FaviconConfiguration（设置图标映射）方法：

		@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);
			}

		}

所有的**/favicon.ico都是在静态资源文件下寻找;

如图：

通过配置文件改变静态资源默认访问路径

ResourceProperties类部分源码：

private static final String[] CLASSPATH_RESOURCE_LOCATIONS = { "classpath:/META-INF/resources/",
			"classpath:/resources/", "classpath:/static/", "classpath:/public/" };

更改相关配置：

spring.resources.static-locations=classpath:/holle,classpath:/godh

放在默认的访问静态资源文件夹中index.html，text.html放在自己配置的访问静态资源的文件夹。如图：

结果，如图：