서블릿 MVC 2

이전글

서블릿 MVC

 

 

이번에는 request 객체에 데이터를 저장했던 이전과 달리 Model을 직접 만들어 사용한다.

 

 

ModelView

public class ModelView {

    private String viewName;
    private Map<String, Object> model = new HashMap<>();
    
    public ModelView(String viewName) {
        this.viewName = viewName;
    }
    
    public String getViewName() {
        return viewName;
    }
    
    public void setViewName(String viewName) {
        this.viewName = viewName;
    }
    
    public Map<String, Object> getModel() {
        return model;
    }
    
    public void setModel(Map<String, Object> model) {
        this.model = model;
    }
}

 

 

Controller

public interface Controller {
    ModelView process(Map<String, String> paramMap);
}

 

 

회원 등록 폼

public class MemberFormController implements Controller {
    
    @Override
    public ModelView process(Map<String, String> paramMap) {
        return new ModelView("new-form");
    }
}

 

 

회원 저장

public class MemberSaveControllerV3 implements ControllerV3 {

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

 

 

회원 목록

public class MemberListControllerV3 implements ControllerV3 {

    private MemberRepository memberRepository = MemberRepository.getInstance();
    
    @Override
    public ModelView process(Map<String, String> paramMap) {
        List<Member> members = memberRepository.findAll();
        
        ModelView mv = new ModelView("members");
        mv.getModel().put("members", members);
        
        return mv;
    }
}

 

 

프론트 컨트롤러

@WebServlet(name = "frontControllerServlet", urlPatterns = "/front-controller/*")
public class FrontControllerServlet extends HttpServlet {

    private Map<String, Controller> controllerMap = new HashMap<>();
    
    public FrontControllerServlet() {
        controllerMap.put("/front-controller/members/new-form", new MemberFormController());
        controllerMap.put("/front-controller/members/save", new MemberSaveController());
        controllerMap.put("/front-controller/members", new MemberListController());
    }
    
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String requestURI = request.getRequestURI();
        
        Controller controller = controllerMap.get(requestURI);
        if (controller == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }
        
        Map<String, String> paramMap = createParamMap(request);
        ModelView mv = controller.process(paramMap);
        
        String viewName = mv.getViewName();
        MyView view = viewResolver(viewName);
        view.render(mv.getModel(), 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");
    }
}

 

 

MyView

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);
    }
    
    public void render(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        modelToRequestAttribute(model, request);
        RequestDispatcher dispatcher = request.getRequestDispatcher(viewPath);
        dispatcher.forward(request, response);
    }
    
    private void modelToRequestAttribute(Map<String, Object> model, HttpServletRequest request) {
        model.forEach((key, value) -> request.setAttribute(key, value));
    }
}