[MVC 구현하기 1, 2단계] 하디(전동혁) 미션 제출합니다.

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

@@ -6,22 +6,32 @@
 import jakarta.servlet.http.HttpServletResponse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import webmvc.org.springframework.web.servlet.view.JspView;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+import webmvc.org.springframework.web.servlet.mvc.asis.ControllerHandlerAdapter;
+import webmvc.org.springframework.web.servlet.mvc.tobe.AnnotationHandlerMapping;
+import webmvc.org.springframework.web.servlet.mvc.tobe.HandlerExecutionHandlerAdapter;
 
 public class DispatcherServlet extends HttpServlet {
 
  private static final long serialVersionUID = 1L;
  private static final Logger log = LoggerFactory.getLogger(DispatcherServlet.class);
 
- private ManualHandlerMapping manualHandlerMapping;
+ private HandlerMappingRegistry handlerMappingRegistry = new HandlerMappingRegistry();
+ private HandlerAdapterRegistry handlerAdapterRegistry = new HandlerAdapterRegistry();
 
  public DispatcherServlet() {
  }
 
  @Override
  public void init() {
- manualHandlerMapping = new ManualHandlerMapping();
- manualHandlerMapping.initialize();
+ handlerMappingRegistry
+ .addHandlerMapping(new ManualHandlerMapping())
+ .addHandlerMapping(new AnnotationHandlerMapping());
+ handlerAdapterRegistry
+ .addHandlerAdapter(new ControllerHandlerAdapter())
+ .addHandlerAdapter(new HandlerExecutionHandlerAdapter());
+ handlerMappingRegistry.initialize();
  }
 
  @Override
@@ -30,22 +40,19 @@ protected void service(final HttpServletRequest request, final HttpServletRespon
  log.debug("Method : {}, Request URI : {}", request.getMethod(), requestURI);
 
  try {
- final var controller = manualHandlerMapping.getHandler(requestURI);
- final var viewName = controller.execute(request, response);
- move(viewName, request, response);
+ Object handler = handlerMappingRegistry.getHandler(request)
+ .orElseThrow(() -> new IllegalArgumentException("There is not matched handler"));
+ HandlerAdapter handlerAdapter = handlerAdapterRegistry.getHandlerAdapter(handler)
+ .orElseThrow(() -> new IllegalArgumentException("Not Supported Handler"));
+ ModelAndView modelAndView = handlerAdapter.handle(request, response, handler);
+ render(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 {
- if (viewName.startsWith(JspView.REDIRECT_PREFIX)) {
- response.sendRedirect(viewName.substring(JspView.REDIRECT_PREFIX.length()));
- return;
- }
-
- final var requestDispatcher = request.getRequestDispatcher(viewName);
- requestDispatcher.forward(request, response);
+ private void render(ModelAndView modelAndView, HttpServletRequest request, HttpServletResponse response) {
+ // TODO: 3단계?
  }
 }

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

@@ -0,0 +1,26 @@
+package com.techcourse;
+
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class HandlerAdapterRegistry {
+
+ private final List<HandlerAdapter> handlerAdapters = new ArrayList<>();
+
+ public HandlerAdapterRegistry addHandlerAdapter(HandlerAdapter handlerAdapter) {
+ handlerAdapters.add(handlerAdapter);
+ return this;
+ }
+
+ public Optional<HandlerAdapter> getHandlerAdapter(Object handler) {
+ for (HandlerAdapter handlerAdapter : handlerAdapters) {
+ if (handlerAdapter.supports(handler)) {
+ return Optional.of(handlerAdapter);
+ }
+ }
+ return Optional.empty();
+ }
+}

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

@@ -0,0 +1,32 @@
+package com.techcourse;
+
+import jakarta.servlet.http.HttpServletRequest;
+import webmvc.org.springframework.web.servlet.mvc.HandlerMapping;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class HandlerMappingRegistry {
+
+ private final List<HandlerMapping> handlerMappings = new ArrayList<>();
+
+ public HandlerMappingRegistry addHandlerMapping(HandlerMapping handlerMapping) {
+ handlerMappings.add(handlerMapping);
+ return this;
+ }
+
+ public void initialize() {
+ handlerMappings.forEach(HandlerMapping::initialize);
+ }
+
+ public Optional<Object> getHandler(HttpServletRequest httpServletRequest) {
+ for (HandlerMapping handlerMapping : handlerMappings) {
+ Object handler = handlerMapping.getHandler(httpServletRequest);
+ if (handler != null) {
+ return Optional.of(handler);
+ }
+ }
+ return Optional.empty();
+ }
+}

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

@@ -0,0 +1,14 @@
+package com.techcourse;
+
+import jakarta.servlet.http.HttpServletRequest;
+import webmvc.org.springframework.web.servlet.mvc.HandlerMapping;
+
+public abstract class LegacyHandlerMapping implements HandlerMapping {
+
+ @Override
+ public Object getHandler(HttpServletRequest httpServletRequest) {
+ return getHandler(httpServletRequest.getRequestURI());
+ }
+
+ public abstract Object getHandler(String requestURI);
+}

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

@@ -9,12 +9,13 @@
 import java.util.HashMap;
 import java.util.Map;
 
-public class ManualHandlerMapping {
+public class ManualHandlerMapping extends LegacyHandlerMapping {
 
  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());
@@ -28,6 +29,7 @@ public void initialize() {
  .forEach(path -> log.info("Path : {}, Controller : {}", path, controllers.get(path).getClass()));
  }
 
+ @Override
  public Controller getHandler(final String requestURI) {
  log.debug("Request Mapping Uri : {}", requestURI);
  return controllers.get(requestURI);

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

@@ -0,0 +1,12 @@
+package webmvc.org.springframework.web.servlet.mvc;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+
+public interface HandlerAdapter {
+
+ boolean supports(Object object);
+
+ ModelAndView handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception;
+}

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

@@ -0,0 +1,10 @@
+package webmvc.org.springframework.web.servlet.mvc;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+public interface HandlerMapping {
+
+ void initialize();
+
+ Object getHandler(HttpServletRequest httpServletRequest);
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/asis/ControllerHandlerAdapter.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.HandlerAdapter;
+import webmvc.org.springframework.web.servlet.view.JspView;
+
+public class ControllerHandlerAdapter implements HandlerAdapter {
+
+ @Override
+ public boolean supports(Object object) {
+ return object instanceof Controller;
+ }
+
+ @Override
+ public ModelAndView handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception {
+ Controller controller = (Controller) handler;
+ String viewName = controller.execute(httpServletRequest, httpServletResponse);
+ ModelAndView mav = new ModelAndView(new JspView(viewName));
+ return mav;
+ }
+}

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

@@ -1,13 +1,18 @@
 package webmvc.org.springframework.web.servlet.mvc.tobe;
 
 import jakarta.servlet.http.HttpServletRequest;
+import org.reflections.Reflections;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import web.org.springframework.web.bind.annotation.RequestMapping;
+import web.org.springframework.web.bind.annotation.RequestMethod;
+import webmvc.org.springframework.web.servlet.mvc.HandlerMapping;
 
-import java.util.HashMap;
-import java.util.Map;
+import java.lang.reflect.Method;
+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);
 
@@ -19,11 +24,60 @@ public AnnotationHandlerMapping(final Object... basePackage) {
  this.handlerExecutions = new HashMap<>();
  }
 
+ @Override
  public void initialize() {
- log.info("Initialized AnnotationHandlerMapping!");
+ log.info("Initializing AnnotationHandlerMapping starts!");
+ for (Object base : basePackage) {
+ ControllerScanner controllerScanner = new ControllerScanner(new Reflections(base));
+ Map<Class<?>, Object> controllers = controllerScanner.getControllers();
+ Set<Method> methods = getRequestMappingMethods(controllers.keySet());
+ for (Method method : methods) {
+ RequestMapping requestMapping = method.getAnnotation(RequestMapping.class);
+ addHandlerExecutions(controllers, method, requestMapping);
+ }
+ }
+ log.info("Initializing AnnotationHandlerMapping succeeds!");
  }
 
+ @Override
  public Object getHandler(final HttpServletRequest request) {
- return null;
+ String uri = request.getRequestURI();
+ try {
+ RequestMethod requestMethod = RequestMethod.valueOf(request.getMethod());
+ HandlerKey handlerKey = new HandlerKey(uri, requestMethod);
+ return handlerExecutions.get(handlerKey);
+ } catch (IllegalArgumentException e) {
+ log.error("Unsupported request method.");
+ return null;
+ }
+ }
+
+ private void addHandlerExecutions(Map<Class<?>, Object> controllers, Method method, RequestMapping requestMapping) {
+ HandlerExecution handlerExecution = mapHandlerExecution(controllers, method);
+ RequestMethod[] requestMethods = requestMapping.method();
+ List<HandlerKey> handlerKeys = mapHandlerKeys(requestMapping.value(), requestMethods);
+ for (HandlerKey handlerKey : handlerKeys) {
+ handlerExecutions.put(handlerKey, handlerExecution);
+ }
+ }
+
+ private HandlerExecution mapHandlerExecution(Map<Class<?>, Object> controllers, Method method) {
+ Object instance = controllers.get(method.getDeclaringClass());
+ return new HandlerExecution(instance, method);
+ }
+
+ private List<HandlerKey> mapHandlerKeys(String url, RequestMethod[] requestMethods) {
+ return Arrays.stream(requestMethods)
+ .map(requestMethod -> new HandlerKey(url, requestMethod))
+ .collect(Collectors.toList());
+ }
+
+ private Set<Method> getRequestMappingMethods(Set<Class<?>> controllers) {
+ return controllers
+ .stream()
+ .map(Class::getMethods)
+ .flatMap(Arrays::stream)
+ .filter(method -> method.isAnnotationPresent(RequestMapping.class))
+ .collect(Collectors.toSet());
  }
 }

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

@@ -0,0 +1,53 @@
+package webmvc.org.springframework.web.servlet.mvc.tobe;
+
+import context.org.springframework.stereotype.Controller;
+import org.reflections.Reflections;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+public class ControllerScanner {
+
+ private static final Logger log = LoggerFactory.getLogger(ControllerScanner.class);
+
+ private final Reflections reflections;
+
+ public ControllerScanner(Reflections reflections) {
+ this.reflections = reflections;
+ }
+
+ public Map<Class<?>, Object> getControllers() {
+ Set<Class<?>> controllers = reflections.getTypesAnnotatedWith(Controller.class);
+ return instantiateControllers(controllers);
+ }
+
+ private Map<Class<?>, Object> instantiateControllers(Set<Class<?>> controllers) {
+ Map<Class<?>, Object> controllerWithInstances = new HashMap<>();
+ try {
+ for (Class<?> controller : controllers) {
+ Object instance = controller.getDeclaredConstructor().newInstance();
+ controllerWithInstances.put(controller, instance);
+ }
+ return controllerWithInstances;
+ } catch (NoSuchMethodException e) {
+ log.error("NoArgConstructor doesn't exist.");
+ } catch (SecurityException e) {
+ log.error("Check permission");
+ } catch (IllegalAccessException e) {
+ log.error("Constructor is not accessible.");
+ } catch (IllegalArgumentException e) {
+ log.error("Type of Arguments doesn't matched.");
+ } catch (InstantiationException e) {
+ log.error("The instance is abstract class.");
+ } catch (InvocationTargetException e) {
+ log.error("Exception occurs during constructing.");
+ } catch (ExceptionInInitializerError error) {
+ log.error("Initializing fails.");
+ }
+ throw new IllegalArgumentException("Getting instance using constructor fails.");
+ }
+}

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

@@ -4,9 +4,19 @@
 import jakarta.servlet.http.HttpServletResponse;
 import webmvc.org.springframework.web.servlet.ModelAndView;
 
+import java.lang.reflect.Method;
+
 public class HandlerExecution {
 
+ private final Object instance;
+ private final Method method;
+
+ public HandlerExecution(Object instance, Method method) {
+ this.instance = instance;
+ this.method = method;
+ }
+
  public ModelAndView handle(final HttpServletRequest request, final HttpServletResponse response) throws Exception {
- return null;
+ return (ModelAndView) method.invoke(instance, request, response);
  }
 }

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

@@ -0,0 +1,19 @@
+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;
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+
+public class HandlerExecutionHandlerAdapter implements HandlerAdapter {
+
+ @Override
+ public boolean supports(Object object) {
+ return object instanceof HandlerExecution;
+ }
+
+ @Override
+ public ModelAndView handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception {
+ return ((HandlerExecution) handler).handle(httpServletRequest, httpServletResponse);
+ }
+}