SpringBoot with Thymeleaf - css not found

If you put your css in the static folder, you dont need the addResourceHandlers method.

.../static/css/app.css

Or if you really want to put them in the assets folder:

.addResourceLocations("classpath:/assets/") <-- without the * at the end
.../assets/css/app/css

in both cases the css should be available through

th:href="@{/css/app.css}"

The problem was the @EnableWebMvc annotation in the Application.java file. As soon as I removed that one, the css started to be available at localhost:8080/css/style.css but was not applied. So far I haven't found the reason why the @EnableWebMvc was causing the problem.

Then I removed a controller mapped to /** that I had implemented in order to display custom error page.

@RequestMapping("/**")
public String notFound() {
    return "errors/404";
}

After removing also this one, I've got my css working. =)

1. Using Custom Resource Path

In your Web Config

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
  if (!registry.hasMappingForPattern("/assets/**")) {
     registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/assets/");
  }
}

Put your style.css file inside this folder

src/main/resources/assets/css/

After that in your views

<link rel="stylesheet" type="text/css" th:href="@{/assets/css/style.css}" />

.

2. Using predefined paths in spring boot

Remove addResourceHandlers from your web config

Put the style.css inside any of the following folders

• src/main/resources/META-INF/resources/assets/css
• src/main/resources/resources/assets/css/
• src/main/resources/static/assets/css/
• src/main/resources/public/assets/css/

And in the view

<link rel="stylesheet" type="text/css" th:href="@{/assets/css/style.css}" />

.

NOTE: You can remove the assets folder here. If you want to do it, remove it from the predefined resource folder and also from the view th:href. But i kept it as it is because, you explicitly mentioned the assets/ path in your question. So I belive it's your requirement to have assets/ in your resource URL.