feat: Controller 및 AbstractController 구현

- Controller interface 구현. service 로직만 구현하였음
- AbstractController 구현. GET,POST 로직이 기본 구현되어 있으며, 이 로직을 호출할 경우 예외를 발생시키고 400 BAD REQUEST를 response에 담아 보낸다. 이 클래스를 상속한 다른 클래스가 구현한 로직이 아니라면 예외를 발생시키는 것.

src/main/java/exception/RequestMethodNotSupportedException.java

@@ -0,0 +1,9 @@
+package exception;
+
+public class RequestMethodNotSupportedException extends RuntimeException {
+    private static final String METHOD_NOT_SUPPORTED_MESSAGE = " 요청을 지원하지 않습니다.";
+
+    public RequestMethodNotSupportedException(String message) {
+        super(message + METHOD_NOT_SUPPORTED_MESSAGE);
+    }
+}

src/main/java/web/request/HttpRequest.java

@@ -85,4 +85,8 @@ public String getAcceptType() {
     public String getRequestHeaderByKey(String key) {
         return httpHeader.getHeaderByKey(key);
     }
+
+    public String getRequestBodyByKey(String key) {
+        return requestBody.getParameterByKey(key);
+    }
 }

src/main/java/web/response/HttpResponse.java

@@ -12,6 +12,7 @@
 import java.util.Objects;
 
 public class HttpResponse {
+    public static final String BAD_REQUEST_ERROR_MESSAGE = "errorMessage : ";
     private static final Logger logger = LoggerFactory.getLogger(HttpResponse.class);
     private static final String HTTP_VERSION = "HTTP/1.1";
 
@@ -42,6 +43,13 @@ public void found(String location) {
         write();
     }
 
+    public void badRequest(String message) {
+        responseLine = new ResponseLine(Status.BAD_REQUEST, HTTP_VERSION);
+        String errorMessage = BAD_REQUEST_ERROR_MESSAGE + message;
+        responseBody = new ResponseBody(errorMessage.getBytes());
+        write();
+    }
+
     private void write() {
         try {
             responseLine.write(dataOutputStream);

src/main/java/web/response/Status.java

@@ -2,7 +2,8 @@
 
 public enum Status {
     OK(200, "OK"),
-    FOUND(302, "FOUND");
+    FOUND(302, "FOUND"),
+    BAD_REQUEST(400, "BAD REQUEST");
 
     private final int code;
     private final String name;

src/main/java/webserver/controller/AbstractController.java

@@ -0,0 +1,32 @@
+package webserver.controller;
+
+import exception.RequestMethodNotSupportedException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import web.request.HttpRequest;
+import web.request.MethodType;
+import web.response.HttpResponse;
+
+public abstract class AbstractController implements Controller {
+    protected static final Logger logger = LoggerFactory.getLogger(Controller.class);
+
+    @Override
+    public void service(HttpRequest request, HttpResponse response) {
+        MethodType method = request.getMethod();
+        if (method.isGet()) {
+            doGet(request, response);
+        } else if (method.isPost()) {
+            doPost(request, response);
+        }
+    }
+
+    protected void doPost(HttpRequest request, HttpResponse response) {
+        response.badRequest("지원하지 않는 POST 요청입니다.");
+        throw new RequestMethodNotSupportedException("POST");
+    }
+
+    protected void doGet(HttpRequest request, HttpResponse response) {
+        response.badRequest("지원하지 않는 GET 요청입니다.");
+        throw new RequestMethodNotSupportedException("GET");
+    }
+}

src/main/java/webserver/controller/Controller.java

@@ -0,0 +1,8 @@
+package webserver.controller;
+
+import web.request.HttpRequest;
+import web.response.HttpResponse;
+
+public interface Controller {
+    void service(HttpRequest request, HttpResponse response);
+}