How can I serve static html from spring boot?

In Spring boot, /META-INF/resources/, /resources/, static/ and public/ directories are available to serve static contents.

So you can create a static/ or public/ directory under resources/ directory and put your static contents there. And they will be accessible by: http://localhost:8080/your-file.ext. (assuming the server.port is 8080)

You can customize these directories using spring.resources.static-locations in the application.properties.

For example:

spring.resources.static-locations=classpath:/custom/

Now you can use custom/ folder under resources/ to serve static files.

This is also possible using Java config in Spring Boot 2:

@Configuration
public class StaticConfig implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("classpath:/custom/");
    }
}

This confugration maps contents of custom directory to the http://localhost:8080/static/** url.

I am using :: Spring Boot :: (v2.0.4.RELEASE) with Spring Framework 5

Spring Boot 2.0 requires Java 8 as a minimum version. Many existing APIs have been updated to take advantage of Java 8 features such as: default methods on interfaces, functional callbacks, and new APIs such as javax.time.

By default, Spring Boot serves 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 that you can modify that behavior by adding your own WebMvcConfigurer and overriding the addResourceHandlers method.

By default, resources are mapped on /** and located on /static directory. But you can customize the static loactions programmatically inside our web context configuration class.

@Configuration @EnableWebMvc
public class Static_ResourceHandler implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        // When overriding default behavior, you need to add default(/) as well as added static paths(/webapp).

        // src/main/resources/static/...
        registry
            //.addResourceHandler("/**") // « /css/myStatic.css
            .addResourceHandler("/static/**") // « /static/css/myStatic.css
            .addResourceLocations("classpath:/static/") // Default Static Loaction
            .setCachePeriod( 3600 )
            .resourceChain(true) // 4.1
            .addResolver(new GzipResourceResolver()) // 4.1
            .addResolver(new PathResourceResolver()); //4.1

        // src/main/resources/templates/static/...
        registry
            .addResourceHandler("/templates/**") // « /templates/style.css
            .addResourceLocations("classpath:/templates/static/");

        // Do not use the src/main/webapp/... directory if your application is packaged as a jar.
        registry
            .addResourceHandler("/webapp/**") // « /webapp/css/style.css
            .addResourceLocations("/");

        // File located on disk
        registry
            .addResourceHandler("/system/files/**")
            .addResourceLocations("file:///D:/");
    }
}

http://localhost:8080/handlerPath/resource-path+name
                    /static         /css/myStatic.css
                    /webapp         /css/style.css
                    /templates      /style.css

In Spring every request will go through the DispatcherServlet. To avoid Static file request through DispatcherServlet(Front contoller) we configure MVC Static content.

As @STEEL said static resources should not go through Controller. Thymleaf is a ViewResolver which takes the view name form controller and adds prefix and suffix to View Layer.

There are three kinds of url in Spring Boot:

1. relative to web application root: eg. "/abc"
2. relative to classpath: eg. "classpath:/abc"
3. relative to file system: eg. "file:/abc"

Return to the subject, in Spring Boot, static resources in the following 4 url can be accessed via "http://localhost:8080/${context root}/${your static resources}".

classpath:/META-INF/resources
classpath:/resources
classpath:/static
classpath:/public

As it is written before, some folders (/META-INF/resources/, /resources/, /static/, /public/) serve static content by default, conroller misconfiguration can break this behaviour.

It is a common pitfall that people define the base url of a controller in the @RestController annotation, instead of the @RequestMapping annotation on the top of the controllers.

This is wrong:

@RestController("/api/base")
public class MyController {

    @PostMapping
    public String myPostMethod( ...) {

The above example will prevent you from opening the index.html. The Spring expects a POST method at the root, because the myPostMethod is mapped to the "/" path.

You have to use this instead:

@RestController
@RequestMapping("/api/base")
public class MyController {

    @PostMapping
    public String myPostMethod( ...) {

I had to add thymeleaf dependency to pom.xml. Without this dependency Spring boot didn't find static resources.

 <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

After creating a bunch of "findme.txt" files, each of which had different "source-relative" path string inside, I found that the following locations can be fetched with "http://host/findme.txt" are:

src/main/resources/public/findme.txt
src/main/resources/static/findme.txt
src/main/resources/resources/findme.txt - (yes, resources^2!)
src/main/resources/findme.txt - not found!!

You can quickly serve static content in JAVA Spring-boot App via thymeleaf (ref: source)

I assume you have already added Spring Boot plugin apply plugin: 'org.springframework.boot' and the necessary buildscript

Then go ahead and ADD thymeleaf to your build.gradle ==>

dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
    compile("org.springframework.boot:spring-boot-starter-thymeleaf")
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

Lets assume you have added home.html at src/main/resources To serve this file, you will need to create a controller.

package com.ajinkya.th.controller;

  import org.springframework.stereotype.Controller;
  import org.springframework.web.bind.annotation.RequestMapping;

  @Controller
  public class HomePageController {

      @RequestMapping("/")
      public String homePage() {
        return "home";
      }

  }

Thats it ! Now restart your gradle server. ./gradlew bootRun