从 Spring 引导中的类路径加载嵌套资源

Question

Spring Boot 2.1.5.RELEASE here. I'm trying to load a resource from a src/main/resources/images directory. My best attempt thus far is:

URL url = getClass().getResource("classpath:images/my_logo.png");
if (url == null) {
  log.warn("Hmmm not found...");
} else {
  log.info("Found it!");
}

At runtime the WARNing " Hmmm not found... " is printing, but the file is absolutely located at src/main/resources/images/my_logo.png . Where am I going awry?

Answer 1

Since you are already using Spring, try using one of their resource loaders

URL url = new PathMatchingResourcePatternResolver( null ).getResource( "classpath:/images/my_logo.png" ).getURL();

Notice: I added a leading slash to the path.

EDIT : I did check on @duffymo's comment and it was correct. The leading slash is not necessary.

Answer 2

There is also another way to retrieve resources in Spring, but the ResourceUtils Javadoc is clear that the class is mainly for internal use.

String file = ResourceUtils.getFile("images/my_logo.png").getAbsolutePath();

Or by using ClassPathResource

URL clsPath =  new ClassPathResource("images/my_logo.png").getURL();