spring mvc : mvc 프레임워크 만들기 - front controller, view 분리

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

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+package com.example.servlet.web.frontcontroller;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class MyView {
+
+    private final String viewPath;
+
+    public MyView(String viewPath) {
+        this.viewPath = viewPath;
+    }
+
+    public void render(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        RequestDispatcher dispatcher = request.getRequestDispatcher(viewPath);
+        dispatcher.forward(request, response);
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v2/ControllerV2.java

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+package com.example.servlet.web.frontcontroller.v2;
+
+import com.example.servlet.web.frontcontroller.MyView;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public interface ControllerV2 {
+
+    MyView process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException;
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v2/FrontControllerServletV2.java

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+package com.example.servlet.web.frontcontroller.v2;
+
+import com.example.servlet.web.frontcontroller.MyView;
+import com.example.servlet.web.frontcontroller.v2.controller.MemberFormControllerV2;
+import com.example.servlet.web.frontcontroller.v2.controller.MemberListControllerV2;
+import com.example.servlet.web.frontcontroller.v2.controller.MemberSaveControllerV2;
+
+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 = "frontControllerServletV2", urlPatterns = "/front-controller/v2/*")
+public class FrontControllerServletV2 extends HttpServlet {
+
+    private final Map<String, ControllerV2> controllerMap = new HashMap<>();
+
+    // 요청 URI 와 controller 매핑
+    public FrontControllerServletV2() {
+        controllerMap.put("/front-controller/v2/members/new-form", new MemberFormControllerV2());
+        controllerMap.put("/front-controller/v2/members/save", new MemberSaveControllerV2());
+        controllerMap.put("/front-controller/v2/members", new MemberListControllerV2());
+    }
+
+    @Override
+    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        String requestURI = request.getRequestURI(); // 요청 URI
+
+        ControllerV2 controller = controllerMap.get(requestURI);
+
+        // 해당 요청의 controller 가 없으면 404 리턴
+        if (controller == null) {
+            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
+            return;
+        }
+
+        MyView view = controller.process(request, response);
+        view.render(request, response);
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v2/controller/MemberFormControllerV2.java

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+package com.example.servlet.web.frontcontroller.v2.controller;
+
+import com.example.servlet.web.frontcontroller.MyView;
+import com.example.servlet.web.frontcontroller.v2.ControllerV2;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class MemberFormControllerV2 implements ControllerV2 {
+
+    @Override
+    public MyView process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        return new MyView("/WEB-INF/views/new-form.jsp");
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v2/controller/MemberListControllerV2.java

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+package com.example.servlet.web.frontcontroller.v2.controller;
+
+import com.example.servlet.domain.member.Member;
+import com.example.servlet.domain.member.MemberRepository;
+import com.example.servlet.web.frontcontroller.MyView;
+import com.example.servlet.web.frontcontroller.v2.ControllerV2;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.List;
+
+public class MemberListControllerV2 implements ControllerV2 {
+
+    private final MemberRepository memberRepository = MemberRepository.getInstance();
+
+    @Override
+    public MyView process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        List<Member> members = memberRepository.findAll();
+        request.setAttribute("members", members);
+        return new MyView("/WEB-INF/views/members.jsp");
+    }
+}

spring-mvc/servlet/src/main/java/com/example/servlet/web/frontcontroller/v2/controller/MemberSaveControllerV2.java

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+package com.example.servlet.web.frontcontroller.v2.controller;
+
+import com.example.servlet.domain.member.Member;
+import com.example.servlet.domain.member.MemberRepository;
+import com.example.servlet.web.frontcontroller.MyView;
+import com.example.servlet.web.frontcontroller.v2.ControllerV2;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class MemberSaveControllerV2 implements ControllerV2 {
+
+    private final MemberRepository memberRepository = MemberRepository.getInstance();
+
+    @Override
+    public MyView 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);
+        request.setAttribute("member", member);
+
+        return new MyView("/WEB-INF/views/save-result.jsp");
+    }
+}