feat(HandlerMapping) : 핸들러 연결할 수 있도록 로직 구현

#13

src/main/java/spring/mvc/handler/mapping/AnnotationHandlerMapping.java

@@ -0,0 +1,62 @@
+package spring.mvc.handler.mapping;
+
+import jakarta.servlet.http.HttpServletRequest;
+import org.reflections.ReflectionUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import spring.mvc.handler.excution.HandlerExecution;
+import spring.mvc.annotation.RequestMapping;
+
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class AnnotationHandlerMapping implements HandlerMapping {
+
+    private static final Logger log = LoggerFactory.getLogger(AnnotationHandlerMapping.class);
+    private Object[] basePackage;
+    private Map<HandlerKey, HandlerExecution> handlerExecutions = new HashMap<>();
+
+    public AnnotationHandlerMapping(Object... basePackage) {
+        this.basePackage = basePackage;
+    }
+
+    public void initialize() {
+        ControllerScanner controllerScanner = new ControllerScanner(basePackage);
+        Map<Class<?>, Object> controllers = controllerScanner.getControllers();
+        Set<Method> methods = getRequestMappingMethods(controllers.keySet());
+
+        for (Method method : methods) {
+            RequestMapping rm = method.getAnnotation(RequestMapping.class);
+            log.debug("register handlerExecution : url is {}, method is {}", rm.value(), rm.method());
+            handlerExecutions.put(createHandlerKey(rm),
+                    new HandlerExecution(controllers.get(method.getDeclaringClass()), method));
+        }
+
+        log.info("Initialized AnnotationHandlerMapping!");
+    }
+
+    private HandlerKey createHandlerKey(RequestMapping rm) {
+        return new HandlerKey(rm.value(), rm.method());
+    }
+
+    @SuppressWarnings("unchecked")
+    private Set<Method> getRequestMappingMethods(Set<Class<?>> controlleers) {
+        Set<Method> requestMappingMethods = new HashSet<>();
+        for (Class<?> clazz : controlleers) {
+            requestMappingMethods
+                    .addAll(ReflectionUtils.getAllMethods(clazz, ReflectionUtils.withAnnotation(RequestMapping.class)));
+        }
+        return requestMappingMethods;
+    }
+
+    @Override
+    public HandlerExecution getHandler(HttpServletRequest request) {
+        String requestUri = request.getRequestURI();
+        RequestMethod rm = RequestMethod.valueOf(request.getMethod().toUpperCase());
+        log.debug("requestUri : {}, requestMethod : {}", requestUri, rm);
+        return handlerExecutions.get(new HandlerKey(requestUri, rm));
+    }
+}

src/main/java/spring/mvc/handler/mapping/HandlerKey.java

@@ -0,0 +1,31 @@
+package spring.mvc.handler.mapping;
+
+import java.util.Objects;
+
+public class HandlerKey {
+    private String url;
+    private RequestMethod method;
+
+    public HandlerKey(String url, RequestMethod method) {
+        this.url = url;
+        this.method = method;
+    }
+
+    @Override
+    public String toString() {
+        return "HandlerKey [url= {}" + url + ", requestMethod=" + method + "]";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        HandlerKey that = (HandlerKey) o;
+        return Objects.equals(url, that.url) && method == that.method;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(url, method);
+    }
+}

src/main/java/spring/mvc/handler/mapping/HandlerMapping.java

@@ -0,0 +1,7 @@
+package spring.mvc.handler.mapping;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+public interface HandlerMapping {
+    Object getHandler(HttpServletRequest request);
+}

src/main/java/spring/mvc/handler/mapping/RequestMethod.java

@@ -0,0 +1,5 @@
+package spring.mvc.handler.mapping;
+
+public enum RequestMethod {
+    GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS, TRACE
+}