Spring Boot系列笔记--静态资源映射规则

一、webjars

• WebJars是以Jar形式为Web项目提供资源文件，然后借助Maven这些依赖库的管理，保证这些Web资源版本唯一性。
• 在spring boot源码中有一个自动配置类WebMvcAutoConfiguration.class，其中关于webjars的代码如下：

  ...
  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(WebMvcAutoConfiguration.getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
                  }
  
              }
          }
  ...
  

  即所有/webjars/** ，都去 classpath:/META-INF/resources/webjars/找资源
• 引入webjars依赖，以jquery和bootstrap为例

  <dependency>
      <groupId>org.webjars</groupId>
      <artifactId>jquery</artifactId>
      <version>3.3.1</version>
  </dependency>
  <dependency>
      <groupId>org.webjars</groupId>
      <artifactId>bootstrap</artifactId>
      <version>4.0.0</version>
  </dependency>
  

• 查看导入的jar包
  
  

二、/**访问当前项目资源

• /**访问当前项目的任何资源，都去（静态资源的文件夹）找映射
• 在ResourceProperties.class中定义了该搜索哪些静态资源文件夹

  private static final String[] CLASSPATH_RESOURCE_LOCATIONS = new String[]{
        
        
      	"classpath:/META-INF/resources/", 
      	"classpath:/resources/", 
      	"classpath:/static/", 
      	"classpath:/public/"
  };
  "/"：当前项目的根路径