spring mvc : mvc 프레임워크 만들기 - front controller 도입

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v1/ControllerV1.java

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+package com.example.servlet.web.frontcontroller.v1;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public interface ControllerV1 {
+
+    void process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException;
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v1/FrontControllerServletV1.java

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+package com.example.servlet.web.frontcontroller.v1;
+
+import com.example.servlet.web.frontcontroller.v1.controller.MemberFormControllerV1;
+import com.example.servlet.web.frontcontroller.v1.controller.MemberListControllerV1;
+import com.example.servlet.web.frontcontroller.v1.controller.MemberSaveControllerV1;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+@WebServlet(name = "frontControllerServletV1", urlPatterns = "/front-controller/v1/*")
+public class FrontControllerServletV1 extends HttpServlet {
+
+    private final Map<String, ControllerV1> controllerMap = new HashMap<>();
+
+    // 요청 URI 와 controller 매핑
+    public FrontControllerServletV1() {
+        controllerMap.put("/front-controller/v1/members/new-form", new MemberFormControllerV1());
+        controllerMap.put("/front-controller/v1/members/save", new MemberSaveControllerV1());
+        controllerMap.put("/front-controller/v1/members", new MemberListControllerV1());
+    }
+
+    @Override
+    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        System.out.println("FrontControllerServletV1.service");
+
+        String requestURI = request.getRequestURI(); // 요청 URI
+
+        ControllerV1 controller = controllerMap.get(requestURI);
+
+        // 해당 요청의 controller 가 없으면 404 리턴
+        if (controller == null) {
+            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
+            return;
+        }
+
+        controller.process(request, response);
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v1/controller/MemberFormControllerV1.java

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+package com.example.servlet.web.frontcontroller.v1.controller;
+
+import com.example.servlet.web.frontcontroller.v1.ControllerV1;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class MemberFormControllerV1 implements ControllerV1 {
+
+    @Override
+    public void process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        String viewPath = "/WEB-INF/views/new-form.jsp";
+        RequestDispatcher dispatcher = request.getRequestDispatcher(viewPath);
+        dispatcher.forward(request, response);
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v1/controller/MemberListControllerV1.java

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+package com.example.servlet.web.frontcontroller.v1.controller;
+
+import com.example.servlet.domain.member.Member;
+import com.example.servlet.domain.member.MemberRepository;
+import com.example.servlet.web.frontcontroller.v1.ControllerV1;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.List;
+
+public class MemberListControllerV1 implements ControllerV1 {
+
+    private final MemberRepository memberRepository = MemberRepository.getInstance();
+
+    @Override
+    public void process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        List<Member> members = memberRepository.findAll();
+
+        request.setAttribute("members", members);
+
+        String viewPath = "/WEB-INF/views/members.jsp";
+        RequestDispatcher dispatcher = request.getRequestDispatcher(viewPath);
+        dispatcher.forward(request, response);
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v1/controller/MemberSaveControllerV1.java

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+package com.example.servlet.web.frontcontroller.v1.controller;
+
+import com.example.servlet.domain.member.Member;
+import com.example.servlet.domain.member.MemberRepository;
+import com.example.servlet.web.frontcontroller.v1.ControllerV1;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class MemberSaveControllerV1 implements ControllerV1 {
+
+    private final MemberRepository memberRepository = MemberRepository.getInstance();
+
+    @Override
+    public void process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        String username = request.getParameter("username");
+        int age = Integer.parseInt(request.getParameter("age"));
+
+        Member member = new Member(username, age);
+        memberRepository.save(member);
+
+        // Model 에 데이터를 보관
+        request.setAttribute("member", member);
+
+        // View 로 이동
+        String viewPath = "/WEB-INF/views/save-result.jsp";
+        RequestDispatcher dispatcher = request.getRequestDispatcher(viewPath);
+        dispatcher.forward(request, response);
+    }
+}