How to fix JSON format issue in JAVA?

Question

This is my 1st project in java spring. So i m trying to figure out the best way to do things.

I have several Rest Apis in my project for which different kinds of API response will be sent.

Somewhere i m getting data in List Format, somewhere else another format. So i m trying to figure out the best way to send response in JSON format.

One of the API Response i have is this:

{
"result": "true",
"message": null,
"data": "{\"id\":1,\"firstName\":\"test\",\"lastName\":\"test\",\"emailId\":\"[email protected]\",\"mobileNo\":\"1234567890\",\"alternateMobileNo\":\"1234567890\",\"username\":\"test\",\"password\":\"7c4a8d09ca3762af61e59520943dc26494f8941b\",\"status\":\"active\",\"userRole\":\"test\",\"dateCreated\":\"Feb 6, 2019\",\"permissions\":\"\"}"
}

My biggest issue is the formatting of data key in the above JSON.

This is my controller action:

@RequestMapping(value = "/admin/staff/get", method = RequestMethod.POST, consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
public Map get(HttpServletRequest request, @RequestParam Map<String, String> parameters) {
 Map<String, String> response = new HashMap<>();
 Gson gson = new Gson();
 Staff staff = new Staff();
 staff.setId(new Integer(parameters.get("id")));
 List validateToken = loginAuthTokenService.validateToken(new Integer(request.getHeader("loginId")), request.getHeader("loginType"), request.getHeader("token"));
 if (validateToken.size() > 0) {
 Staff staffDetails = staffService.getStaff(staff.getId());
 response.put("result", "true");
 response.put("data", gson.toJson(staffDetails));
 } else {
 response.put("result", "false");
 response.put("message", "No records found.");
 }
 return response;
}

Should I create a separate Class for sending API Response or anyone please guide me the proper way of sending response.

Thanks

Answer 1

Gson#toJson(Object) returns a String and that String is mapped as JSON key in your map.

You don't have to convert your object to a JSON, Spring will do it for you (it uses Jackson as JSON mapper so you don't have add Gson dependency to your project.

A simple and working implementation could be something like:

@RequestMapping(value = "/admin/staff/get", method = RequestMethod.POST, consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
public ResponseEntity<?> get(
 @RequestParam("id") Integer id,
 @RequestHeader("loginId") Integer loginId,
 @RequestHeader("loginType") String loginType, 
 @RequestHeader("token") String token) {
 List validateToken = loginAuthTokenService.validateToken(loginId, loginType, token);
 if (!validateToken.isEmpty()) {
 Stuff stuff = staffService.getStaff(id);
 return ResponseEntity.ok(stuff);
 }
 return ResponseEntity.notFound().body("No records found.");
}

---

Also consider to not return a generic map from your method, but the Stuff object your front-end needs. In case of failure you should return a failure object with a specific http response code (e.g. 404, 400, 500...).

Take a look at this guide.

• Ravinder Singh: If i will do this, how will i send response.put("result", "true"); since "true" is not an object?
• noiaverbale: "true" is a String, a String is an Object. By the way, take a look at my last edit to the answer.
• Ravinder Singh: I see, but @ResponseStatus(value = HttpStatus.OK) i will have to use above the function, how do i send different kinds of response based on data available or not like i did true/false ?
• noiaverbale: Either by returning a ResponseEntity with proper http code or throwing an exception in your method and using a ControllerAdvise to handle it like the linked guide says (there plenty of guides, I just linked you the first I found in Google)
• noiaverbale: Here, this article may be better

Answer 2

To format the the data attribute , you can store it in a map :-

Map<String, Object> map1= new HashMap<String, Object>();

and is you have multiple data attributes you can create an ArrayList of Maps :-

ArrayList<Map<String, Object>> dataClerk = new ArrayList<Map<String,Object>>();

I had a similar usecas so i used the below code :-

obj = parser.parse(response);
JSONObject jobj = (JSONObject)parser.parse(response); 
JSONArray jsonarr_1 = (JSONArray) jobj.get(item);
for(int i=0 ;i<jsonarr_1.size();i++) {
 Map<String, Object> entry = new HashMap<String, Object>();
 org.json.simple.JSONObject temp= (org.json.simple.JSONObject) 
 jsonarr_1.get(i);
 Set<String> attributes= temp.keySet();
 for(String s: attributes) {
 entry.put(s, temp.get(s));
 }
 }