Serving Static resources from file system | Spring Boot Web - spring-mvc

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

Answer 4

static resources (eg:html js css etc) can be placed in the same level directory of project or jar, named public. contents will be servered without additional config.