[MVC 구현하기 - 2단계] 망고(고재철) 미션 제출합니다. (#531)

* feat: HandlerMapping 인터페이스 구현

* feat: HandlerAdapter 인터페이스 및 ManualHandlerAdapter, AnnotationHandlerAdapter 구현

* feat: HandlerMappings, HandlerAdapters 구현

* feat: 인터페이스 기반, 어노테이션 기반 동시 지원하도록 DispatcherServlet 구현

* refactor: 어노테이션 방식으로 RegisterController 변경

* refactor: RegisterController URI 매핑 수정

* refactor: Override 어노테이션 추가

Author: Go-Jaecheol

app/src/main/java/com/techcourse/DispatcherServlet.java

@@ -6,40 +6,50 @@
 import jakarta.servlet.http.HttpServletResponse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.mvc.asis.ManualHandlerAdapter;
+import webmvc.org.springframework.web.servlet.mvc.tobe.AnnotationHandlerAdapter;
+import webmvc.org.springframework.web.servlet.mvc.tobe.AnnotationHandlerMapping;
 import webmvc.org.springframework.web.servlet.view.JspView;
 
 public class DispatcherServlet extends HttpServlet {
 
     private static final long serialVersionUID = 1L;
     private static final Logger log = LoggerFactory.getLogger(DispatcherServlet.class);
 
-    private ManualHandlerMapping manualHandlerMapping;
+    private final transient HandlerMappings handlerMappings;
+    private final transient HandlerAdapters handlerAdapters;
 
     public DispatcherServlet() {
+        this.handlerMappings = new HandlerMappings();
+        this.handlerAdapters = new HandlerAdapters();
     }
 
     @Override
     public void init() {
-        manualHandlerMapping = new ManualHandlerMapping();
-        manualHandlerMapping.initialize();
+        handlerMappings.addHandlerMapping(new ManualHandlerMapping());
+        handlerMappings.addHandlerMapping(new AnnotationHandlerMapping());
+        handlerAdapters.addHandlerAdapter(new ManualHandlerAdapter());
+        handlerAdapters.addHandlerAdapter(new AnnotationHandlerAdapter());
     }
 
     @Override
     protected void service(final HttpServletRequest request, final HttpServletResponse response) throws ServletException {
-        final String requestURI = request.getRequestURI();
-        log.debug("Method : {}, Request URI : {}", request.getMethod(), requestURI);
+        log.debug("Method : {}, Request URI : {}", request.getMethod(), request.getRequestURI());
 
         try {
-            final var controller = manualHandlerMapping.getHandler(requestURI);
-            final var viewName = controller.execute(request, response);
-            move(viewName, request, response);
+            final var handler = handlerMappings.getHandler(request);
+            final var handlerAdapter = handlerAdapters.getHandlerAdapter(handler);
+            final ModelAndView modelAndView = handlerAdapter.handle(request, response, handler);
+            move(modelAndView, request, response);
         } catch (Throwable e) {
             log.error("Exception : {}", e.getMessage(), e);
             throw new ServletException(e.getMessage());
         }
     }
 
-    private void move(final String viewName, final HttpServletRequest request, final HttpServletResponse response) throws Exception {
+    private void move(final ModelAndView modelAndView, final HttpServletRequest request, final HttpServletResponse response) throws Exception {
+        final String viewName = modelAndView.getView().getViewName();
         if (viewName.startsWith(JspView.REDIRECT_PREFIX)) {
             response.sendRedirect(viewName.substring(JspView.REDIRECT_PREFIX.length()));
             return;

app/src/main/java/com/techcourse/HandlerAdapters.java

@@ -0,0 +1,26 @@
+package com.techcourse;
+
+import webmvc.org.springframework.web.servlet.mvc.tobe.HandlerAdapter;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class HandlerAdapters {
+
+    private final List<HandlerAdapter> adapters;
+
+    public HandlerAdapters() {
+        this.adapters = new ArrayList<>();
+    }
+
+    public void addHandlerAdapter(final HandlerAdapter handlerAdapter) {
+        adapters.add(handlerAdapter);
+    }
+
+    public HandlerAdapter getHandlerAdapter(final Object handler) {
+        return adapters.stream()
+                .filter(it -> it.supports(handler))
+                .findFirst()
+                .orElseThrow(IllegalArgumentException::new);
+    }
+}

app/src/main/java/com/techcourse/HandlerMappings.java

@@ -0,0 +1,30 @@
+package com.techcourse;
+
+import jakarta.servlet.http.HttpServletRequest;
+import webmvc.org.springframework.web.servlet.mvc.tobe.HandlerMapping;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+public class HandlerMappings {
+
+    private final List<HandlerMapping> mappings;
+
+    public HandlerMappings() {
+        this.mappings = new ArrayList<>();
+    }
+
+    public void addHandlerMapping(final HandlerMapping handlerMapping) {
+        handlerMapping.initialize();
+        mappings.add(handlerMapping);
+    }
+
+    public Object getHandler(final HttpServletRequest request) {
+        return mappings.stream()
+                .map(it -> it.getHandler(request))
+                .filter(Objects::nonNull)
+                .findFirst()
+                .orElseThrow(IllegalStateException::new);
+    }
+}

app/src/main/java/com/techcourse/ManualHandlerMapping.java

@@ -1,34 +1,39 @@
 package com.techcourse;
 
-import com.techcourse.controller.*;
+import com.techcourse.controller.LoginController;
+import com.techcourse.controller.LoginViewController;
+import com.techcourse.controller.LogoutController;
+import jakarta.servlet.http.HttpServletRequest;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import webmvc.org.springframework.web.servlet.mvc.asis.Controller;
 import webmvc.org.springframework.web.servlet.mvc.asis.ForwardController;
+import webmvc.org.springframework.web.servlet.mvc.tobe.HandlerMapping;
 
 import java.util.HashMap;
 import java.util.Map;
 
-public class ManualHandlerMapping {
+public class ManualHandlerMapping implements HandlerMapping {
 
     private static final Logger log = LoggerFactory.getLogger(ManualHandlerMapping.class);
 
     private static final Map<String, Controller> controllers = new HashMap<>();
 
+    @Override
     public void initialize() {
         controllers.put("/", new ForwardController("/index.jsp"));
         controllers.put("/login", new LoginController());
         controllers.put("/login/view", new LoginViewController());
         controllers.put("/logout", new LogoutController());
-        controllers.put("/register/view", new RegisterViewController());
-        controllers.put("/register", new RegisterController());
 
         log.info("Initialized Handler Mapping!");
         controllers.keySet()
                 .forEach(path -> log.info("Path : {}, Controller : {}", path, controllers.get(path).getClass()));
     }
 
-    public Controller getHandler(final String requestURI) {
+    @Override
+    public Controller getHandler(final HttpServletRequest request) {
+        final String requestURI = request.getRequestURI();
         log.debug("Request Mapping Uri : {}", requestURI);
         return controllers.get(requestURI);
     }

app/src/main/java/com/techcourse/controller/RegisterController.java

@@ -2,20 +2,30 @@
 
 import com.techcourse.domain.User;
 import com.techcourse.repository.InMemoryUserRepository;
+import context.org.springframework.stereotype.Controller;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
-import webmvc.org.springframework.web.servlet.mvc.asis.Controller;
+import web.org.springframework.web.bind.annotation.RequestMapping;
+import web.org.springframework.web.bind.annotation.RequestMethod;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.view.JspView;
 
-public class RegisterController implements Controller {
+@Controller
+public class RegisterController {
 
-    @Override
-    public String execute(final HttpServletRequest req, final HttpServletResponse res) throws Exception {
+    @RequestMapping(value = "/register", method = RequestMethod.POST)
+    public ModelAndView save(final HttpServletRequest request, final HttpServletResponse response) {
         final var user = new User(2,
-                req.getParameter("account"),
-                req.getParameter("password"),
-                req.getParameter("email"));
+                request.getParameter("account"),
+                request.getParameter("password"),
+                request.getParameter("email"));
         InMemoryUserRepository.save(user);
 
-        return "redirect:/index.jsp";
+        return new ModelAndView(new JspView("redirect:/index.jsp"));
+    }
+
+    @RequestMapping(value = "/register/view", method = RequestMethod.GET)
+    public ModelAndView show(final HttpServletRequest request, final HttpServletResponse response) {
+        return new ModelAndView(new JspView("/register.jsp"));
     }
 }

app/src/main/java/com/techcourse/controller/RegisterViewController.java

@@ -7,4 +7,6 @@
 
 public interface View {
     void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) throws Exception;
+
+    String getViewName();
 }

mvc/src/main/java/webmvc/org/springframework/web/servlet/View.java

@@ -0,0 +1,23 @@
+package webmvc.org.springframework.web.servlet.mvc.asis;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.mvc.tobe.HandlerAdapter;
+import webmvc.org.springframework.web.servlet.view.JspView;
+
+public class ManualHandlerAdapter implements HandlerAdapter {
+
+    @Override
+    public boolean supports(final Object handler) {
+        return handler instanceof Controller;
+    }
+
+    @Override
+    public ModelAndView handle(final HttpServletRequest request, final HttpServletResponse response, final Object handler)
+            throws Exception {
+        final var controller = (Controller) handler;
+        final String viewName = controller.execute(request, response);
+        return new ModelAndView(new JspView(viewName));
+    }
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/asis/ManualHandlerAdapter.java

@@ -0,0 +1,20 @@
+package webmvc.org.springframework.web.servlet.mvc.tobe;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+
+public class AnnotationHandlerAdapter implements HandlerAdapter {
+
+    @Override
+    public boolean supports(final Object handler) {
+        return handler instanceof HandlerExecution;
+    }
+
+    @Override
+    public ModelAndView handle(final HttpServletRequest request, final HttpServletResponse response, final Object handler)
+            throws Exception {
+        final var handlerExecution = (HandlerExecution) handler;
+        return handlerExecution.handle(request, response);
+    }
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/tobe/AnnotationHandlerAdapter.java

@@ -12,7 +12,7 @@
 import java.util.*;
 import java.util.stream.Collectors;
 
-public class AnnotationHandlerMapping {
+public class AnnotationHandlerMapping implements HandlerMapping {
 
     private static final Logger log = LoggerFactory.getLogger(AnnotationHandlerMapping.class);
 
@@ -24,6 +24,7 @@ public AnnotationHandlerMapping(final Object... basePackage) {
         this.handlerExecutions = new HashMap<>();
     }
 
+    @Override
     public void initialize() {
         final var reflections = new Reflections(basePackage);
         final Set<Class<?>> controllerClasses = reflections.getTypesAnnotatedWith(Controller.class);
@@ -57,6 +58,7 @@ private void addHandlerExecution(final Method method, final RequestMapping reque
         }
     }
 
+    @Override
     public Object getHandler(final HttpServletRequest request) {
         final String requestURI = request.getRequestURI();
         final var requestMethod = RequestMethod.valueOf(request.getMethod());