EmailVerificationController.java

package com.royalrangers.controller;

import com.google.gson.*;
import com.royalrangers.security.repository.UserRepository;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@Slf4j
@RestController
public class EmailVerificationController {

    @Autowired
    private UserRepository userRepository;

    @PostMapping("/open/checkEmail")
    public ResponseEntity<?> checkEmail(@RequestBody String email) {

        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        JsonObject responseJson = new JsonObject();
        HttpStatus status = null;

            try {
                JsonElement jsonElement = new JsonParser().parse(email);
                JsonObject jsonObject = jsonElement.getAsJsonObject();
                String mail = jsonObject.get("email").getAsString();

                log.info("checking email: " + mail);

                int count = userRepository.countByEmail(mail);
                if (count > 0) {
                    responseJson.addProperty("exist", true);
                    responseJson.addProperty("message", "user with this email already exist");
                } else {
                    responseJson.addProperty("exist", false);
                    responseJson.addProperty("message", "user with this email not exist");
                }
                status = HttpStatus.OK;
            } catch (JsonSyntaxException | NullPointerException e) {
                responseJson.addProperty("message", "Illegal request");
                status = HttpStatus.BAD_REQUEST;
            } catch (Exception e) {
                responseJson.addProperty("message", e.getMessage());
                status = HttpStatus.INTERNAL_SERVER_ERROR;
            }
        return new ResponseEntity<String>(gson.toJson(responseJson), null , status);
    }
}