Serving static index without viewresolver - spring-boot

Question

I want to build a basic project with two controllers, one serving static pages and the other one with REST endpoints defined. I don't need any view resolver for that so that's what I put together:
#SpringBootApplication
#Controller
public class MyAppApplication extends SpringBootServletInitializer {
public static void main(String[] args) {
SpringApplication.run(MyAppApplication.class, args);
}
#RequestMapping("/")
public String index() {
return "index";
}
}
And My pom.xml:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
my index.html is under src/main/resources/ and I've tried to return index, index.html as well as full path but I still end up getting 404 error.
Am I missing or misunderstanding something?

Answer 1

Serving static content:
By default Spring Boot will serve static content from a directory called /static (or /public or /resources or /META-INF/resources) in the classpath or from the root of the ServletContext. It uses the ResourceHttpRequestHandler from Spring MVC so you can modify that behavior by adding your own WebMvcConfigurerAdapter and overriding the addResourceHandlers method.
In a stand-alone web application the default servlet from the container is also enabled, and acts as a fallback, serving content from the root of the ServletContext if Spring decides not to handle it. Most of the time this will not happen (unless you modify the default MVC configuration) because Spring will always be able to handle requests through the DispatcherServlet.
By default, resources are mapped on /** but you can tune that via spring.mvc.static-path-pattern. For instance, relocating all resources to /resources/** can be achieved as follows
spring.mvc.static-path-pattern=/resources/**
You can also customize the static resource locations using spring.resources.static-locations (replacing the default values with a list of directory locations). If you do this the default welcome page detection will switch to your custom locations, so if there is an index.html in any of your locations on startup, it will be the home page of the application.
DispatcherServlet maintains a list of implementations to use by default. This information is kept in the file DispatcherServlet.properties in the package org.springframework.web.servlet.
For example it’s quite common to configure an InternalResourceViewResolver settings its prefix property to the parent location of view files.
Regardless of the details, the important concept to understand here is that once you configure a special bean such as an InternalResourceViewResolver in your WebApplicationContext, you effectively override the list of default implementations that would have been used otherwise for that special bean type. For example if you configure an InternalResourceViewResolver, the default list of ViewResolver implementations is ignored.
http://docs.spring.io/spring/docs/5.0.0.RC2/spring-framework-reference/web.html#mvc-servlet-config
See the example in github