[MVC 구현하기 - 1단계] 유콩(김유빈) 미션 제출합니다. (#169)

* docs: 1단계 체크리스트 작성

* feat: @controller 읽어와 핸들러 추가

* feat: 핸들러 메서드 실행

* feat: DispatcherServlet 초기화 시 어노테이션 기반 핸들러 매핑 추가

* feat: HandlerAdapter 이용하여 Handler 실제 로직 수행

* feat: ModelAndView rendering

README.md

@@ -1 +1,5 @@
 # @MVC 구현하기
+
+## 🚀 1단계 - @MVC 프레임워크 구현하기
+- [x] AnnotationHandlerMappingTest가 정상 동작한다.
+- [x] DispatcherServlet에서 HandlerMapping 인터페이스를 활용하여 AnnotationHandlerMapping과 ManualHandlerMapping 둘다 처리할 수 있다.

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

@@ -2,6 +2,8 @@
 
 import jakarta.servlet.ServletContext;
 import nextstep.mvc.DispatcherServlet;
+import nextstep.mvc.controller.tobe.AnnotationHandlerAdapter;
+import nextstep.mvc.controller.tobe.AnnotationHandlerMapping;
 import nextstep.web.WebApplicationInitializer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -13,12 +15,20 @@ public class AppWebApplicationInitializer implements WebApplicationInitializer {
     @Override
     public void onStartup(final ServletContext servletContext) {
         final var dispatcherServlet = new DispatcherServlet();
-        dispatcherServlet.addHandlerMapping(new ManualHandlerMapping());
+        addHandlerMappingAndAdapter(dispatcherServlet);
 
         final var dispatcher = servletContext.addServlet("dispatcher", dispatcherServlet);
         dispatcher.setLoadOnStartup(1);
         dispatcher.addMapping("/");
 
         log.info("Start AppWebApplication Initializer");
     }
+
+    private void addHandlerMappingAndAdapter(final DispatcherServlet dispatcherServlet) {
+        dispatcherServlet.addHandlerMapping(new ManualHandlerMapping());
+        dispatcherServlet.addHandlerMapping(new AnnotationHandlerMapping());
+
+        dispatcherServlet.addHandlerAdapter(new ManualHandlerAdapter());
+        dispatcherServlet.addHandlerAdapter(new AnnotationHandlerAdapter());
+    }
 }

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

@@ -0,0 +1,21 @@
+package com.techcourse;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import nextstep.mvc.HandlerAdapter;
+import nextstep.mvc.controller.asis.Controller;
+import nextstep.mvc.view.ModelAndView;
+
+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 String viewName = ((Controller) handler).execute(request, response);
+        return new ModelAndView(viewName);
+    }
+}

mvc/src/main/java/nextstep/mvc/DispatcherServlet.java

@@ -4,13 +4,14 @@
 import jakarta.servlet.http.HttpServlet;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
-import nextstep.mvc.controller.asis.Controller;
-import nextstep.mvc.view.JspView;
+import nextstep.mvc.view.ModelAndView;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 public class DispatcherServlet extends HttpServlet {
@@ -19,9 +20,11 @@ public class DispatcherServlet extends HttpServlet {
     private static final Logger log = LoggerFactory.getLogger(DispatcherServlet.class);
 
     private final List<HandlerMapping> handlerMappings;
+    private final List<HandlerAdapter> handlerAdapters;
 
     public DispatcherServlet() {
         this.handlerMappings = new ArrayList<>();
+        this.handlerAdapters = new ArrayList<>();
     }
 
     @Override
@@ -33,36 +36,48 @@ public void addHandlerMapping(final HandlerMapping handlerMapping) {
         handlerMappings.add(handlerMapping);
     }
 
+    public void addHandlerAdapter(final HandlerAdapter handlerAdapter) {
+        handlerAdapters.add(handlerAdapter);
+    }
+
     @Override
     protected void service(final HttpServletRequest request, final HttpServletResponse response) throws ServletException {
         log.debug("Method : {}, Request URI : {}", request.getMethod(), request.getRequestURI());
 
         try {
-            final var controller = getController(request);
-            final var viewName = controller.execute(request, response);
-            move(viewName, request, response);
+            final Object handler = getHandler(request);
+            final ModelAndView modelAndView = getModelAndView(handler, request, response);
+            final Map<String, Object> model = modelAndView.getModel();
+            modelAndView.getView().render(model, request, response);
         } catch (Throwable e) {
             log.error("Exception : {}", e.getMessage(), e);
             throw new ServletException(e.getMessage());
         }
     }
 
-    private Controller getController(final HttpServletRequest request) {
+    private Object getHandler(final HttpServletRequest request) {
         return handlerMappings.stream()
                 .map(handlerMapping -> handlerMapping.getHandler(request))
                 .filter(Objects::nonNull)
-                .map(Controller.class::cast)
                 .findFirst()
                 .orElseThrow();
     }
 
-    private void move(final String viewName, final HttpServletRequest request, final HttpServletResponse response) throws Exception {
-        if (viewName.startsWith(JspView.REDIRECT_PREFIX)) {
-            response.sendRedirect(viewName.substring(JspView.REDIRECT_PREFIX.length()));
-            return;
-        }
+    private ModelAndView getModelAndView(final Object handler, final HttpServletRequest request, final HttpServletResponse response) {
+        return handlerAdapters.stream()
+            .filter(handlerAdapter -> handlerAdapter.supports(handler))
+            .map(handlerAdapter -> getModelAndView(handler, request, response, handlerAdapter))
+            .findFirst()
+            .orElseThrow();
+    }
 
-        final var requestDispatcher = request.getRequestDispatcher(viewName);
-        requestDispatcher.forward(request, response);
+    private ModelAndView getModelAndView(final Object handler,
+        final HttpServletRequest request, final HttpServletResponse response, final HandlerAdapter handlerAdapter
+    ){
+        try {
+            return handlerAdapter.handle(request, response, handler);
+        } catch (Exception e) {
+            throw new IllegalArgumentException(String.format("적절하지 않은 handler 입니다. [%s]", handler));
+        }
     }
 }

mvc/src/main/java/nextstep/mvc/controller/tobe/AnnotationHandlerAdapter.java

@@ -0,0 +1,20 @@
+package nextstep.mvc.controller.tobe;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import nextstep.mvc.HandlerAdapter;
+import nextstep.mvc.view.ModelAndView;
+import nextstep.web.annotation.Controller;
+
+public class AnnotationHandlerAdapter implements HandlerAdapter {
+
+    @Override
+    public boolean supports(final Object handler) {
+        return handler.getClass().isAnnotationPresent(Controller.class);
+    }
+
+    @Override
+    public ModelAndView handle(final HttpServletRequest request, final HttpServletResponse response, final Object handler) throws Exception {
+        return ((HandlerExecution) handler).handle(request, response);
+    }
+}

mvc/src/main/java/nextstep/mvc/controller/tobe/AnnotationHandlerMapping.java

@@ -2,11 +2,18 @@
 
 import jakarta.servlet.http.HttpServletRequest;
 import nextstep.mvc.HandlerMapping;
+import nextstep.web.annotation.Controller;
+import nextstep.web.annotation.RequestMapping;
+import nextstep.web.support.RequestMethod;
+
+import org.reflections.Reflections;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.lang.reflect.Method;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 
 public class AnnotationHandlerMapping implements HandlerMapping {
 
@@ -20,11 +27,55 @@ public AnnotationHandlerMapping(final Object... basePackage) {
         this.handlerExecutions = new HashMap<>();
     }
 
+    @Override
     public void initialize() {
+        final Reflections reflections = new Reflections(basePackage);
+        final Set<Class<?>> controllers = reflections.getTypesAnnotatedWith(Controller.class);
+        for (final Class<?> controller : controllers) {
+            addRequestMappingMethod(controller);
+        }
         log.info("Initialized AnnotationHandlerMapping!");
     }
 
+    @Override
     public Object getHandler(final HttpServletRequest request) {
-        return null;
+        final HandlerKey handlerKey = new HandlerKey(request.getRequestURI(), RequestMethod.from(request.getMethod()));
+        log.info("request handler [{}]", handlerKey);
+        if (!handlerExecutions.containsKey(handlerKey)) {
+            throw new IllegalArgumentException(String.format("요청한 핸들러가 존재하지 않습니다. [%s]", handlerKey));
+        }
+        final HandlerExecution handlerExecution = handlerExecutions.get(handlerKey);
+        log.info("search handler [{}]", handlerExecution);
+        return handlerExecution;
+    }
+
+    private void addRequestMappingMethod(final Class<?> controller) {
+        final Method[] methods = controller.getMethods();
+        for (final Method method : methods) {
+            if (!method.isAnnotationPresent(RequestMapping.class)) {
+                continue;
+            }
+            final RequestMapping requestMapping = method.getAnnotation(RequestMapping.class);
+            addHandlerExecution(controller, requestMapping, method);
+        }
+    }
+
+    private void addHandlerExecution(final Class<?> controller, final RequestMapping requestMapping, final Method method) {
+        for (final RequestMethod requestMethod : requestMapping.method()) {
+            final HandlerKey handlerKey = new HandlerKey(requestMapping.value(), requestMethod);
+            if (handlerExecutions.containsKey(handlerKey)) {
+                throw new IllegalArgumentException(String.format("중복적으로 매핑되었습니다. [%s]", handlerKey));
+            }
+            handlerExecutions.put(handlerKey, getHandlerExecution(controller, method));
+        }
+    }
+
+    private HandlerExecution getHandlerExecution(final Class<?> controller, final Method method) {
+        try {
+            final Object newInstance = controller.getConstructor().newInstance();
+            return new HandlerExecution(newInstance, method);
+        } catch (Exception e) {
+            throw new IllegalArgumentException(String.format("기본 생성자가 존재하지 않습니다. [%s]", controller));
+        }
     }
 }

mvc/src/main/java/nextstep/mvc/controller/tobe/HandlerExecution.java

@@ -1,12 +1,37 @@
 package nextstep.mvc.controller.tobe;
 
+import java.lang.reflect.Method;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import nextstep.mvc.view.ModelAndView;
 
 public class HandlerExecution {
 
+    private final static Logger log = LoggerFactory.getLogger(HandlerExecution.class);
+
+    private final Object clazz;
+    private final Method method;
+
+    public HandlerExecution(final Object clazz, final Method method) {
+        this.clazz = clazz;
+        this.method = method;
+    }
+
     public ModelAndView handle(final HttpServletRequest request, final HttpServletResponse response) throws Exception {
-        return null;
+        final ModelAndView modelAndView = (ModelAndView) method.invoke(clazz, request, response);
+        log.info("execute controller method [{}]", method);
+        return modelAndView;
+    }
+
+    @Override
+    public String toString() {
+        return "HandlerExecution{" +
+            "clazz=" + clazz +
+            ", method=" + method +
+            '}';
     }
 }

mvc/src/main/java/nextstep/mvc/view/JsonView.java

@@ -7,6 +7,12 @@
 
 public class JsonView implements View {
 
+    private final String body;
+
+    public JsonView(final String body) {
+        this.body = body;
+    }
+
     @Override
     public void render(final Map<String, ?> model, final HttpServletRequest request, HttpServletResponse response) throws Exception {
     }

mvc/src/main/java/nextstep/mvc/view/JspView.java

@@ -1,10 +1,12 @@
 package nextstep.mvc.view;
 
+import jakarta.servlet.RequestDispatcher;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
 import java.util.Map;
 
 public class JspView implements View {
@@ -13,18 +15,41 @@ public class JspView implements View {
 
     public static final String REDIRECT_PREFIX = "redirect:";
 
+    private final String viewName;
+    private final boolean redirect;
+
     public JspView(final String viewName) {
+        validateJsp(viewName);
+        if (viewName.startsWith(REDIRECT_PREFIX)) {
+            this.viewName = viewName.substring(JspView.REDIRECT_PREFIX.length());
+            this.redirect = true;
+            return;
+        }
+        this.viewName = viewName;
+        this.redirect = false;
+    }
+
+    private void validateJsp(final String viewName) {
+        if (!viewName.endsWith(".jsp")) {
+            throw new IllegalArgumentException(String.format("JSP 형식이 아닙니다. [%s]", viewName));
+        }
     }
 
     @Override
     public void render(final Map<String, ?> model, final HttpServletRequest request, final HttpServletResponse response) throws Exception {
-        // todo
-
+        addLocation(response);
         model.keySet().forEach(key -> {
             log.debug("attribute name : {}, value : {}", key, model.get(key));
             request.setAttribute(key, model.get(key));
         });
 
-        // todo
+        final RequestDispatcher requestDispatcher = request.getRequestDispatcher(viewName);
+        requestDispatcher.forward(request, response);
+    }
+
+    private void addLocation(final HttpServletResponse response) throws IOException {
+        if (redirect) {
+            response.sendRedirect(viewName);
+        }
     }
 }

mvc/src/main/java/nextstep/mvc/view/ModelAndView.java

@@ -9,6 +9,10 @@ public class ModelAndView {
     private final View view;
     private final Map<String, Object> model;
 
+    public ModelAndView(final String viewName) {
+        this(getView(viewName));
+    }
+
     public ModelAndView(final View view) {
         this.view = view;
         this.model = new HashMap<>();
@@ -19,6 +23,13 @@ public ModelAndView addObject(final String attributeName, final Object attribute
         return this;
     }
 
+    private static View getView(String viewName) {
+        if (viewName.endsWith(".jsp")) {
+            return new JspView(viewName);
+        }
+        return new JsonView(viewName);
+    }
+
     public Object getObject(final String attributeName) {
         return model.get(attributeName);
     }

mvc/src/main/java/nextstep/web/support/RequestMethod.java

@@ -1,5 +1,16 @@
 package nextstep.web.support;
 
+import java.util.Arrays;
+
 public enum RequestMethod {
+
     GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS, TRACE
+    ;
+
+    public static RequestMethod from(final String value) {
+        return Arrays.stream(values())
+            .filter(method -> method.name().equals(value.toUpperCase()))
+            .findFirst()
+            .orElseThrow(() -> new IllegalArgumentException(String.format("정의되지 않은 메서드입니다. [%s]", value)));
+    }
 }