[Spring Boot] Controller vs RestController

package wordle.wordle.controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.ArrayNode;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import wordle.wordle.utils.JsonConverter;

@RestController
@RequestMapping("/wordle")
public class WordleController {

    @RequestMapping(method=RequestMethod.GET, path="/")
    public String home(Model model){
        System.out.println("GET HOME");
        model.addAttribute("data", "hello wordle!");
        return "wordle";
    }

    @RequestMapping(method=RequestMethod.GET, path="/lookup")
    public static ArrayNode word(@RequestParam String word) throws Exception{
        String dictionaryUrl = String.format("https://api.dictionaryapi.dev/api/v2/entries/en/%s", word);
        URL url = new URL(dictionaryUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        int responseCode = connection.getResponseCode();
        System.out.println("Response Code: " + responseCode);

        ObjectMapper objectMapper = new ObjectMapper();
        ArrayNode jsonResponse = objectMapper.createArrayNode();

        if (responseCode == HttpURLConnection.HTTP_OK) {
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            StringBuilder response = new StringBuilder();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            String responseBody = response.toString();
            JsonConverter jsonConverter = new JsonConverter();
            jsonResponse = jsonConverter.convertStringToJsonArray(responseBody);
//            System.out.println("Response Body: " + jsonResponse);
            connection.disconnect();
        }
        else if (responseCode == HttpURLConnection.HTTP_NOT_FOUND) {
            ObjectNode objectNode = objectMapper.createObjectNode();
            objectNode.put("msg", "It does not exist!");
            jsonResponse.add(objectNode);
        }
        return jsonResponse;
    }
}

 

 

위 Class에서 

• /wordle 로 GET Request를 전송했을 때는, resources/templates/wordle.html이 반환되고
• /wordle/lookup?word=[검색할 단어] 로 GET Request를 전송했을 때는, JSON 데이터가 반환되길 기대했다.

하지만 /wordle로 GET Request를 전송했을때는 아래와 같은 오류가 발생함

 

 

/wordle/ 로 GET Request 전송시에는 오류는 나지 않지만, 기대했던 html 파일이 아닌 String이 반환됨

 

 

왜 이러는거야~!~!~!

 

찾아보니 RestController를 사용했기 때문에 html이 반환되지 않은 것 같았다.

 

간략하게 정리하면

@RestController은 @Controller와 @ResponseBody의 조합
RESTful 웹 서비스 개발을 용이하게 하기 위해 Spring 4.0에서 추가된 어노테이션임

@Controller은 Model 객체를 매개변수로 전달받아 주로 View를 반환하기 위해 사용함

 

참고

https://dncjf64.tistory.com/288

@Controller와 @RestController의 차이점

 

 

---

아래와 같이 코드를 수정하여 해결~!

 

package wordle.wordle.controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.ArrayNode;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import wordle.wordle.utils.JsonConverter;

@Controller
@RequestMapping("/wordle")
public class WordleController {

    @RequestMapping(method=RequestMethod.GET, path="")
    public String home(Model model){
        System.out.println("GET HOME");
        model.addAttribute("data", "wordle!");
        return "wordle";
    }

    @RequestMapping(method=RequestMethod.GET, path="/lookup")
    public static @ResponseBody ArrayNode word(@RequestParam String word) throws Exception{
        String dictionaryUrl = String.format("https://api.dictionaryapi.dev/api/v2/entries/en/%s", word);
        URL url = new URL(dictionaryUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        int responseCode = connection.getResponseCode();
        System.out.println("Response Code: " + responseCode);

        ObjectMapper objectMapper = new ObjectMapper();
        ArrayNode jsonResponse = objectMapper.createArrayNode();

        if (responseCode == HttpURLConnection.HTTP_OK) {
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            StringBuilder response = new StringBuilder();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            String responseBody = response.toString();
            JsonConverter jsonConverter = new JsonConverter();
            jsonResponse = jsonConverter.convertStringToJsonArray(responseBody);
//            System.out.println("Response Body: " + jsonResponse);
            connection.disconnect();
        }
        else if (responseCode == HttpURLConnection.HTTP_NOT_FOUND) {
            ObjectNode objectNode = objectMapper.createObjectNode();
            objectNode.put("msg", "It does not exist!");
            jsonResponse.add(objectNode);
        }
        return jsonResponse;
    }
}

 

 

• GET /wordle

 

• GET /wordle/lookup?word=love

 

 

 

• (참고) wordle.html

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Hello</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<p th:text="'Welcome to ' + ${data}" ></p>
</body>
</html>