getStringFromResource.java

    @Value("classpath:ololo.properties")
    //@Value("file:/home/nik/ideaWorkspace/blog/backend/src/main/resources/ololo.properties")
    Resource resource;

    @GetMapping(value = "/ololo", produces = TEXT_HTML_VALUE)
    public String getOlolo() throws IOException {

        try(BufferedReader br = new BufferedReader(new InputStreamReader(resource.getInputStream()));) {
            return br.lines().collect(Collectors.joining("\n"));
        }
    }