springmvc之ModelAndView的使用详解

一时失言乱红尘 2022-04-03 02:51 315阅读 0赞

### 一.前言 ###

ModelAndView类用来存储处理完后的结果数据，以及显示该数据的视图,其中Model代表模型，View代表视图。业务处理器调用模型层处理完用户请求后，把结果数据存储在该类的model属性中，把要返回的视图信息存储在该类的view属性中，然后让该ModelAndView返回该Spring MVC框架。框架通过调用配置文件中定义的视图解析器，对该对象进行解析，最后把结果数据显示在指定的view页面。

### 二.主要功能 ###

##### 1.跳转指定页面且传递参数 #####

下面利用springboot和thyemeleaf模板引擎测试

@GetMapping("/regist")
        public ModelAndView regist(){ 
            ModelAndView view = new ModelAndView("regist");
            User user = new User("lss0555","123456");
            view.addObject("name","lss");
            view.addObject("user",user);
            return view;
        }

其中regist.html页面

<!DOCTYPE html>
    <html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
    <head>
        <meta charset="UTF-8">
    </head>
    <body>
      <div>
          <div>  name: <span th:text="${name}"/></div>
    
          <div>  username: <span th:text="${user.username}"/></div>
          <div>  password: <span th:text="${user.password}"/></div>
    
      </div>
    </body>
    </html>

访问/regist,结果:

name: lss
    username: lss0555
    password: 123456

### 三.源码 ###

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by Fernflower decompiler)
    //
    
    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();
        }
    }