How do I use Spring Boot to serve static content located in Dropbox folder?

I have a Spring Boot web application, and I would like to serve static content located in a shared Dropbox directory on my Linode VPS (~/Dropbox/images). I've read that Spring Boot will automatically serve static content from

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

but of course my Dropbox directory is not on the classpath.

Although I could configure Apache to serve the images in my Dropbox folder, I would like to take advantage of Spring Security to restrict access of the static content to authenticated users.

You can add your own static resource handler (it overwrites the default), e.g.

@Configuration
public class StaticResourceConfiguration extends WebMvcConfigurerAdapter {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/**").addResourceLocations("file:/path/to/my/dropbox/");
    }
}

There is some documentation about this in Spring Boot, but it's really just a vanilla Spring MVC feature.

Also since spring boot 1.2 (I think) you can simply set spring.resources.staticLocations.

Springboot (via Spring) now makes adding to existing resource handlers easy. See Dave Syers answer. To add to the existing static resource handlers, simply be sure to use a resource handler path that doesn't override existing paths.

The two "also" notes below are still valid.

. . .

[Edit: The approach below is no longer valid]

If you want to extend the default static resource handlers, then something like this seems to work:

@Configuration
@AutoConfigureAfter(DispatcherServletAutoConfiguration.class)
public class CustomWebMvcAutoConfig extends
                    WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter {

  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
    String myExternalFilePath = "file:///C:/Temp/whatever/m/";

    registry.addResourceHandler("/m/**").addResourceLocations(myExternalFilePath);

    super.addResourceHandlers(registry);
  }

}

The call to super.addResourceHandlers sets up the default handlers.

Also:

• Note the trailing slash on the external file path. (Depends on your expectation for URL mappings).
• Consider reviewing the source code of WebMvcAutoConfigurationAdapter.

Based on @Dave Syers answer I add the following class to my Spring Boot project:

@Configuration
public class StaticResourceConfiguration extends WebMvcConfigurerAdapter {

 private static final Logger LOG = LoggerFactory.getLogger(StaticResourceConfiguration.class);

 @Value("${static.path}")
 private String staticPath;

 @Override
 public void addResourceHandlers(ResourceHandlerRegistry registry) {

	if(staticPath != null) {
		LOG.info("Serving static content from " + staticPath);
		registry.addResourceHandler("/**").addResourceLocations("file:" + staticPath);
	}
 }

 // see https://stackoverflow.com/questions/27381781/java-spring-boot-how-to-map-my-my-app-root-to-index-html
 @Override
 public void addViewControllers(ViewControllerRegistry registry) {
 	registry.addViewController("/").setViewName("redirect:/index.html");
 }
}

This allows me to start my spring boot app with the parameter --static.path like

java -jar spring-app-1.0-SNAPSHOT.jar --static.path=/path/to/my/static-files/

This can be very handy for development and testing.

There's a property spring.resources.staticLocations that can be set in the application.properties. Note that this will override the default locations. See org.springframework.boot.autoconfigure.web.ResourceProperties.

• OS: Win 10
• Spring Boot: 2.1.2

I wanted to serve static content from c:/images

Adding this property worked for me:

spring.resources.static-locations=classpath:/META-INF/resources/,classpath:/resources/,classpath:/static/,classpath:/public/,file:///C:/images/

I found the original value of the property in the Spring Boot Doc Appendix A

This will make c:/images/image.jpg to be accessible as http://localhost:8080/image.jpg

@Mark Schäfer

Never too late, but add a slash (/) after static:

spring.resources.static-locations=file:/opt/x/y/z/static/

So http://<host>/index.html is now reachable.

Based on @Dave Syer, @kaliatech and @asmaier answers the springboot v2+ way would be:

@Configuration
@AutoConfigureAfter(DispatcherServletAutoConfiguration.class)
public class StaticResourceConfiguration implements WebMvcConfigurer  {

  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
	String myExternalFilePath = "file:///C:/temp/whatever/m/";

	 registry.addResourceHandler("/m/**").addResourceLocations(myExternalFilePath);

  }

}

To serve from file system

I added spring.resources.static-location=file:../frontend/build in application.properties

index.html is present in the build folder

Use can also add absolute path

spring.resources.static-location=file:/User/XYZ/Desktop/frontend/build

I think similarly you can try adding Dropbox folder path.

For the current Spring-Boot Version 1.5.3 the parameter is

spring.resources.static-locations

Update I configured

`spring.resources.static-locations=file:/opt/x/y/z/static``

and expected to get my index.html living in this folder when calling

http://<host>/index.html

This did not work. I had to include the folder name in the URL:

http://<host>/static/index.html

FWIW, I didn't have any success with the spring.resources.static-locations recommended above; what worked for me was setting spring.thymeleaf.prefix:

report.location=file:/Users/bill/report/html/
spring.thymeleaf.prefix=${report.location}

Note that WebMvcConfigurerAdapter is deprecated now (see WebMvcConfigurerAdapter). Due to Java 8 default methods, you only have to implement WebMvcConfigurer.

You can place your folder in the root of the ServletContext.

Then specify a relative or absolute path to this directory in application.yml:

spring:
  resources:
    static-locations: file:some_temp_files/

The resources in this folder will be available (for downloading, for example) at:

http://<host>:<port>/<context>/your_file.csv