[Spring] MVC _ 개발자를 위한 기능 개선

기능 개선

 

매번 ModelView 객체를 생성하지 않고, 컨트롤러가 ModelView를 반환하지 않고 ViewName만 반환한다.

 

인터페이스에는 ModelView가 없으며, model 객체를 파라미터로 전달하기 때문에 그냥 사용하면 된다. 결과적으로 viewName만 반환해주면 된다.

public interface ControllerV4 {
    /**
     *
     * @param paramMap
     * @param model
     * @return viewName
     */
    String process(Map<String, String> paramMap, Map<String, Object> model);
}

 

ControllerV4 인터페이스를 준수하는 컨트롤러도 마찬가지로 viewName만 반환하도록 설정한다. 대신 파라미터로 전달되는 model에 비즈니스 로직을 반영하여야 한다.

public class MemberFormControllerV4 implements ControllerV4 {
    @Override
    public String process(Map<String, String> paramMap, Map<String, Object>
            model) {
        return "new-form";
    }
}


public class MemberListControllerV4 implements ControllerV4 {
    private MemberRepository memberRepository = MemberRepository.getInstance();
    @Override
    public String process(Map<String, String> paramMap, Map<String, Object>
            model) {
        List<Member> members = memberRepository.findAll();
        model.put("members", members);
        return "members";
    }
}

public class MemberSaveControllerV4 implements ControllerV4 {

    private MemberRepository memberRepository = MemberRepository.getInstance();

    @Override
    public String process(Map<String, String> paramMap, Map<String, Object> model) {
        String username = paramMap.get("username");
        int age = Integer.parseInt(paramMap.get("age"));
        Member member = new Member(username, age);
        memberRepository.save(member);
        model.put("member", member);
        return "save-result";
    }
}

 

FrontController도 model을 정의하고, 컨트롤러에 전달하는 것이 추가된다. 

@WebServlet(name = "frontControllerServletV4", urlPatterns = "/front-controller/v4/*")
public class FrontControllerServletV4 extends HttpServlet {
    private Map<String, ControllerV4> controllerMap = new HashMap<>();

    public FrontControllerServletV4() {
        controllerMap.put("/front-controller/v4/members/new-form", new MemberFormControllerV4());
        controllerMap.put("/front-controller/v4/members/save", new MemberSaveControllerV4());
        controllerMap.put("/front-controller/v4/members", new MemberListControllerV4());
    }

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String requestURI = request.getRequestURI();

        ControllerV4 controller = controllerMap.get(requestURI);
        if (controller == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        Map<String, String> paramMap = createParamMap(request);
        
        // model 정의
        Map<String, Object> model = new HashMap<>();

        String viewName = controller.process(paramMap, model);
        MyView view = viewResolver(viewName);
        view.render(model, request, response);
    }

    private Map<String, String> createParamMap(HttpServletRequest request) {
        Map<String, String> paramMap = new HashMap<>();
        request.getParameterNames().asIterator()
                .forEachRemaining(paramName -> paramMap.put(paramName,
                        request.getParameter(paramName)));
        return paramMap;
    }

    private MyView viewResolver(String viewName) {
        return new MyView("/WEB-INF/views/" + viewName + ".jsp");
    }
}