[Java][Spring] View 분리 -V2

View 분리 -v2

MyView

package hello.servlet.web.frontcontroller;

import jakarta.servlet.RequestDispatcher;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;

public class MyView {
    private 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);
    }
}

• 프론트 컨트롤러의 도입으로 MyView 객체의 render() 를 호출하는 부분을 모두 일관되게 처리할 수 있다. 각각의 컨트롤러는 MyView 객체를 생성만 해서 반환하면 된다.

ControllerV2

package hello.servlet.web.frontcontroller.v2;

import hello.servlet.web.frontcontroller.MyView;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;

public interface ControllerV2 {
    MyView process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException;

}

• 각 컨트롤러는 복잡한 dispatcher.forward() 를 직접 생성해서 호출하지 않아도 된다.
  • 중복 제거
• 단순히 MyView 객 체를 생성하고 거기에 뷰 이름만 넣고 반환

MemberFormControllerV2

package hello.servlet.web.frontcontroller.v2.controller;

import hello.servlet.web.frontcontroller.MyView;
import hello.servlet.web.frontcontroller.v2.ControllerV2;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.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");
    }
}

MemberSaveControllerV2

package hello.servlet.web.frontcontroller.v2.controller;

import hello.servlet.domain.member.Member;
import hello.servlet.domain.member.MemberRepository;
import hello.servlet.web.frontcontroller.MyView;
import hello.servlet.web.frontcontroller.v2.ControllerV2;
import jakarta.servlet.RequestDispatcher;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;

public class MemberSaveControllerV2 implements ControllerV2 {
    private 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);

        // Model에 데이터 저장
        request.setAttribute("member",member);

        return new MyView("/WEB-INF/views/save-result.jsp");
    }
}

MemberListControllerV2

package hello.servlet.web.frontcontroller.v2.controller;

import hello.servlet.domain.member.Member;
import hello.servlet.domain.member.MemberRepository;
import hello.servlet.web.frontcontroller.MyView;
import hello.servlet.web.frontcontroller.v2.ControllerV2;
import jakarta.servlet.RequestDispatcher;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.util.List;

public class MemberListControllerV2 implements ControllerV2 {
    private 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");
    }
}

FrontControllerServletV2

package hello.servlet.web.frontcontroller.v2;

import hello.servlet.web.frontcontroller.MyView;
import hello.servlet.web.frontcontroller.v2.controller.MemberFormControllerV2;
import hello.servlet.web.frontcontroller.v2.controller.MemberListControllerV2;
import hello.servlet.web.frontcontroller.v2.controller.MemberSaveControllerV2;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.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 Map<String, ControllerV2> controllerV2Map = new HashMap<>();

    public FrontControllerServletV2(){
        controllerV2Map.put("/front-controller/v2/members/new-form",new MemberFormControllerV2());
        controllerV2Map.put("/front-controller/v2/members/save",new MemberSaveControllerV2());
        controllerV2Map.put("/front-controller/v2/members",new MemberListControllerV2());
    }

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String requestURI = request.getRequestURI();

        ControllerV2 controller = controllerV2Map.get(requestURI);
        if (controller == null){
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }
        // new MyView("/WEB-INF/views/members.jsp");
        MyView view = controller.process(request,response);
        view.render(request,response);
    }
}

• ControllerV2의 반환 타입이 MyView 이므로 프론트 컨트롤러는 컨트롤러의 호출 결과로MyView 를 반환.
• view.render() 를 호출하면 forward 로직을 수행해서 JSP가 실행된다.