How to pass JSON from static file to rest controller SpringBoot App

Question

I have a stable SpringBoot project that runs. I want to add a end point that reads a json file from classpath and passes it through to the response without having to create any Model objects (pass thru).

I have no issues reading the json file into JsonNode or ObjectNode, I'm struggling with where to go next to set the data in my response object.

Added this caveat later, I do need to update the json from a database.

Answer 1

Ok, paired up with a colleague at work and we tried two things, return a string (escapes strings in REST output - returns a big String.) not good. What worked is setting the response object to a and calling mapper.readValue(jsonFeed, Map.class), that returned the JSON in proper object notation.

    @Value("${metadata.json.file}") //defined in application.context
    private Resource metaJsonFileName;

    public String getJsonFromFile(List<UnitUiItem> uiitems){
        JsonNode root;
        ObjectMapper mapper = new ObjectMapper();
        InputStream stream = metaJsonFileName.getInputStream();

        root = mapper.readTree(stream);
        JsonNode dataNode = root.get("data");
        JsonNode optionDataNode = dataNode.get("storelocation");

        ((ObjectNode)optionDataNode).putArray("units");
       for(UnitUiItem item : uiitems){
        JsonNode unitNode = ((ObjectNode)optionDataNode).withArray("units").addObject();
        ((ObjectNode)unitNode).put("code",item.getCode());
        ((ObjectNode)unitNode).put("displayName",item.getDisplayName());
    }

    LOGGER.info("buildMetaJson exit");
    return root.toString();
    }

    //calling method
    String jsonFeed = getJsonFromFile();
    ObjectMapper mapper = new ObjectMapper();
    response.setData(mapper.readValue(jsonFeed, Map.class));

I have some code cleanup to do.. any cleaner ways of doing this?