SpringBoot系列九：静态资源

静态资源的映射规则。在SpringBoot项目中mvc的相关配置都在 WebMvcAutoConfiguration 中。

@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties implements ResourceLoaderAware {
   //可以设置和静态资源有关的参数，缓存时间等
}

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
	if (!this.resourceProperties.isAddMappings()) {
		logger.debug("Default resource handling disabled");
		return;
	}
	Integer cachePeriod = this.resourceProperties.getCachePeriod();
	if (!registry.hasMappingForPattern("/webjars/**")) {
		customizeResourceHandlerRegistration(
				registry.addResourceHandler("/webjars/**")
						.addResourceLocations(
								"classpath:/META-INF/resources/webjars/")
				.setCachePeriod(cachePeriod));
	}
	String staticPathPattern = this.mvcProperties.getStaticPathPattern();
        	//静态资源文件夹映射
	if (!registry.hasMappingForPattern(staticPathPattern)) {
		customizeResourceHandlerRegistration(
				registry.addResourceHandler(staticPathPattern)
						.addResourceLocations(
								this.resourceProperties.getStaticLocations())
				.setCachePeriod(cachePeriod));
	}
}

1、所有 /webjars/** ，都去 classpath:/META-INF/resources/webjars/ 找资源；webjars 就是以jar包的方式引入静态资源。webjars 官网：http://www.webjars.org/

<!--引入jquery-webjar-->
<dependency>
    <groupId>org.webjars</groupId>
    <artifactId>jquery</artifactId>
    <version>3.3.1</version>
</dependency>

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/3.3.1/jquery.js

2、/**访问当前项目的任何资源，都去静态资源的文件夹里面找。

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

3、欢迎页，静态资源文件夹下的所有index.html页面；被 /** 映射。

//配置欢迎页映射
@Bean
public WelcomePageHandlerMapping welcomePageHandlerMapping(
		ResourceProperties resourceProperties) {
	return new WelcomePageHandlerMapping(resourceProperties.getWelcomePage(),
			this.mvcProperties.getStaticPathPattern());
}

4、所有的 **/favicon.ico 都是在静态资源文件下找。

//配置喜欢的图标
@Configuration
@ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
public static class FaviconConfiguration {

	private final ResourceProperties resourceProperties;

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

	@Bean
	public SimpleUrlHandlerMapping faviconHandlerMapping() {
		SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
		mapping.setOrder(Ordered.HIGHEST_PRECEDENCE + 1);
            	//所有  **/favicon.ico 
		mapping.setUrlMap(Collections.singletonMap("**/favicon.ico",
				faviconRequestHandler()));
		return mapping;
	}

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

}