Serving Static resources from file system | Spring Boot Web

Question

Using a Spring Boot web application I trying to serve my static resource from a file system folder outside my project.

Folder structure looks like:-

          src
             main
                 java
                 resources
             test
                 java
                 resources
          pom.xml
          ext-resources   (I want to keep my static resources here)
                 test.js

Spring Configuration:-

@SpringBootApplication
public class DemoStaticresourceApplication extends WebMvcConfigurerAdapter {

    public static void main(String[] args) {
        SpringApplication.run(DemoStaticresourceApplication.class, args);
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/test/**").addResourceLocations("file:///./ext-resources/")
                .setCachePeriod(0);
    }
}

Hitting 'http://localhost:9999/test/test.js' in my browser gives back a 404.

How should I configure ResourceHandlerRegistry to serve static resources from the above mentioned 'ext-resources' folder?

I should be able to switch cache on/off for dev/prod environment.

Thanks

UPDATE 1

Giving absolute file path works:-

@Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/test/**")
                .addResourceLocations(
                        "file:///C:/Sambhav/Installations/workspace/demo-staticresource/ext-resources/")
                .setCachePeriod(0);
}

How can I provide relative location? Absolute path will make my life tough during build & deploy process.

Answer 1

file:/// is an absolute URL pointing to the root of the filesystem and, therefore, file:///./ext-resources/ means that Spring Boot is looking for resources in a directory named ext-resources in the root.

Update your configuration to use something like file:ext-resources/ as the URL.

Answer 2

This is what I did in the WebConfig class, inside the addResourceHandlers method:

boolean devMode = this.env.acceptsProfiles("development");
String location;
if (devMode) {
    String currentPath = new File(".").getAbsolutePath();
    location = "file:///" + currentPath + "/client/src/";
} else {
    location = "classpath:static/";
}

Answer 3

Spring Boot Maven Plugin can add extra directories to the classpath. In your case you could include that in your pom.

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <version>${spring.boot.version}</version>
    <configuration>
        <folders>
            <folder>${project.build.directory}/../ext-resources</folder>
        </folders>

        ...
    </configuration>
</plugin>

So that way you don't need inlcude any hard-code in your classes. Simply start your webapp with

mvn spring-boot:run