modelandview란?

ModelAndView

org.springframework.web.servelt 패키지에 속해있는 클래스로 컨트롤러의 처리결과를 보여줄 뷰와 전달할 값을 저장할 용도로 쓰인다.

ModelAndView클래스를 보면 다음과 같이 구성되어 있다.

package org.springframework.web.servlet;

import java.util.Map;
import org.springframework.http.HttpStatus;
import org.springframework.ui.ModelMap;
import org.springframework.util.CollectionUtils;

public class ModelAndView {
    private Object view;
    private ModelMap model;
    private HttpStatus status;
    private boolean cleared = false;

    public ModelAndView() {
    }

    public ModelAndView(String viewName) {
        this.view = viewName;
    }

    public ModelAndView(View view) {
        this.view = view;
    }

    public ModelAndView(String viewName, Map<String, ?> model) {
        this.view = viewName;
        if (model != null) {
            this.getModelMap().addAllAttributes(model);
        }

    }

    public ModelAndView(View view, Map<String, ?> model) {
        this.view = view;
        if (model != null) {
            this.getModelMap().addAllAttributes(model);
        }

    }

    public ModelAndView(String viewName, HttpStatus status) {
        this.view = viewName;
        this.status = status;
    }

    public ModelAndView(String viewName, Map<String, ?> model, HttpStatus status) {
        this.view = viewName;
        if (model != null) {
            this.getModelMap().addAllAttributes(model);
        }

        this.status = status;
    }

    public ModelAndView(String viewName, String modelName, Object modelObject) {
        this.view = viewName;
        this.addObject(modelName, modelObject);
    }

    public ModelAndView(View view, String modelName, Object modelObject) {
        this.view = view;
        this.addObject(modelName, modelObject);
    }

    public void setViewName(String viewName) {
        this.view = viewName;
    }

    public String getViewName() {
        return this.view instanceof String ? (String)this.view : null;
    }

    public void setView(View view) {
        this.view = view;
    }

    public View getView() {
        return this.view instanceof View ? (View)this.view : null;
    }

    public boolean hasView() {
        return this.view != null;
    }

    public boolean isReference() {
        return this.view instanceof String;
    }

    protected Map<String, Object> getModelInternal() {
        return this.model;
    }

    public ModelMap getModelMap() {
        if (this.model == null) {
            this.model = new ModelMap();
        }

        return this.model;
    }

    public Map<String, Object> getModel() {
        return this.getModelMap();
    }

    public void setStatus(HttpStatus status) {
        this.status = status;
    }

    public HttpStatus getStatus() {
        return this.status;
    }

    public ModelAndView addObject(String attributeName, Object attributeValue) {
        this.getModelMap().addAttribute(attributeName, attributeValue);
        return this;
    }

    public ModelAndView addObject(Object attributeValue) {
        this.getModelMap().addAttribute(attributeValue);
        return this;
    }

    public ModelAndView addAllObjects(Map<String, ?> modelMap) {
        this.getModelMap().addAllAttributes(modelMap);
        return this;
    }

    public void clear() {
        this.view = null;
        this.model = null;
        this.cleared = true;
    }

    public boolean isEmpty() {
        return this.view == null && CollectionUtils.isEmpty(this.model);
    }

    public boolean wasCleared() {
        return this.cleared && this.isEmpty();
    }

    public String toString() {
        StringBuilder sb = new StringBuilder("ModelAndView: ");
        if (this.isReference()) {
            sb.append("reference to view with name '").append(this.view).append("'");
        } else {
            sb.append("materialized View is [").append(this.view).append(']');
        }

        sb.append("; model is ").append(this.model);
        return sb.toString();
    }
}

다음과 같이 map에 데이터를 담거나 직접 값을 전달해 줄 수있다.

@RequestMapping(value="list")
  public ModelAndView list(@RequestParam(defaultValue="title") String searchOption,
    @RequestParam(defaultValue="") String keyword,
    @RequestParam(defaultValue="1") int curPage) throws Exception{

  //전달할 정보 가져오기
  int count = adminService.countboard(searchOption, keyword);
  BoardPage boardPage = new BoardPage(count, curPage);
  int start = boardPage.getPageBegin();
  int end = boardPage.getPageEnd();
  List<WebBoard> list = adminService.Viewlist(start, end, searchOption, keyword);

  //전달할 정보 map에 담기
  Map<String, Object> map = new HashMap<String, Object>();
  map.put("list", list);
  map.put("searchOption", searchOption);
  map.put("keyword", keyword);
  map.put("boardPage", boardPage);


  ModelAndView mav = new ModelAndView();

  //ModelAndView 객체에 전달할 정보(map)과 뷰 설정하기
  mav.addObject("map", map);
  //map에 넣지않고 직접 전달해도 된다.
  mav.addObject("count",count);
  mav.setViewName("/admin/adminmode");

  return mav;
  }

ModelAndView 외에도 다양하게 컨트롤러의 리턴타입을 정할 수 있음.

@ReqeustMapping("/list/")
  public String list(Model model){

    int count = adminService.countboard();

    model.addAttribute("count", count);

    return "/admin/adminmode"
  }