RestController 인터셉터 추가

.gitignore

@@ -40,4 +40,5 @@ bin/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store
+.omx/

src/main/java/com/diy/framework/context/RestController.java

@@ -0,0 +1,12 @@
+package com.diy.framework.context;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Component
+public @interface RestController {
+}

src/main/java/com/diy/framework/web/DispatcherServlet.java

@@ -1,9 +1,11 @@
 package com.diy.framework.web;
 
 import com.diy.framework.context.HandlerMethod;
+import com.diy.framework.context.RestController;
 import com.diy.framework.web.beans.factory.BeanFactory;
 import com.diy.framework.web.mvc.ModelAndView;
 import com.diy.framework.web.mvc.controller.HandlerMapping;
+import com.diy.framework.web.mvc.json.JsonResponseWriter;
 import com.diy.framework.web.mvc.view.JspViewResolver;
 import com.diy.framework.web.mvc.view.ViewResolver;
 
@@ -23,6 +25,7 @@ public class DispatcherServlet extends HttpServlet {
 
     private HandlerMapping handlerMapping;
     private final ViewResolver viewResolver = new JspViewResolver();
+    private final JsonResponseWriter jsonResponseWriter = new JsonResponseWriter();
 
     @Override
     public void init() throws ServletException {
@@ -57,11 +60,15 @@ private void execute(Object handler, HttpServletRequest req, HttpServletResponse
 
             if (handler instanceof HandlerMethod handlerMap) {
                 Object controller = ((HandlerMethod) handler).getBean();
+                Class<?> controllerClass = controller.getClass();
                 Method method = ((HandlerMethod) handler).getMethod();
 
                 // Reflection 으로 메서드 실행
                 Object result = method.invoke(controller, req, resp);
-                if (result instanceof ModelAndView modelAndView) {
+
+                if (controllerClass.isAnnotationPresent(RestController.class)) {
+                    jsonResponseWriter.write(resp, result);
+                } else if (result instanceof ModelAndView modelAndView) {
                     viewResolver.resolveViewName(modelAndView.getViewName()).render(req, resp, modelAndView.getModel());
                 }
             }

src/main/java/com/diy/framework/web/mvc/json/JsonResponseWriter.java

@@ -0,0 +1,23 @@
+package com.diy.framework.web.mvc.json;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectWriter;
+
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.PrintWriter;
+
+/*
+ * Json 응답을 만들기 위한 클래스
+ * */
+public class JsonResponseWriter {
+
+    private static ObjectMapper objectMapper = new ObjectMapper();
+
+    public void write(HttpServletResponse response, Object object) throws IOException {
+        response.setContentType("application/json; charset=UTF-8");
+        String json = objectMapper.writeValueAsString(object);
+        response.getWriter().write(json);
+    }
+}