ModelAndViewContainer、ModelMap、Model、ModelAndView详细介绍【享学Spring MVC】（下）

public class BindingAwareModelMap extends ExtendedModelMap {
  // 注解复写了Map的put方法，一下子就拦截了所有的addAttr方法。。。
  @Override
  public Object put(String key, Object value) {
    removeBindingResultIfNecessary(key, value);
    return super.put(key, value);
  }
  @Override
  public void putAll(Map<? extends String, ?> map) {
    map.forEach(this::removeBindingResultIfNecessary);
    super.putAll(map);
  }
  // 本类处理的逻辑：
  private void removeBindingResultIfNecessary(Object key, Object value) {
    // key必须是String类型才会给与处理
    if (key instanceof String) {
      String attributeName = (String) key;
      if (!attributeName.startsWith(BindingResult.MODEL_KEY_PREFIX)) {
        String bindingResultKey = BindingResult.MODEL_KEY_PREFIX + attributeName;
        BindingResult bindingResult = (BindingResult) get(bindingResultKey);
        // 如果有校验结果，并且放进来的value值不是绑定结果本身，那就移除掉绑定结果（相当于覆盖掉）
        if (bindingResult != null && bindingResult.getTarget() != value) {
          remove(bindingResultKey);
        }
      }
    }
  }
}

public class ModelAndView {
  @Nullable
  private Object view; // 可以是View，也可以是String
  @Nullable
  private ModelMap model;
  // 显然，你也可以自己就放置好一个http状态码进去
  @Nullable
  private HttpStatus status;  
  // 标记这个实例是否被调用过clear()方法~~~
  private boolean cleared = false;
  // 总共这几个属性：它提供的构造函数非常的多  这里我就不一一列出
  public void setViewName(@Nullable String viewName) {
    this.view = viewName;
  }
  public void setView(@Nullable View view) {
    this.view = view;
  }
  @Nullable
  public String getViewName() {
    return (this.view instanceof String ? (String) this.view : null);
  }
  @Nullable
  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方法~~~
  @Nullable
  protected Map<String, Object> getModelInternal() {
    return this.model;
  }
  public ModelMap getModelMap() {
    if (this.model == null) {
      this.model = new ModelMap();
    }
    return this.model;
  }
  // 操作ModelMap的一些方法如下：
  // addObject/addAllObjects
  public void clear() {
    this.view = null;
    this.model = null;
    this.cleared = true;
  }
  // 前提是：this.view == null 
  public boolean isEmpty() {
    return (this.view == null && CollectionUtils.isEmpty(this.model));
  }
  // 竟然用的was，歪果仁果然严谨  哈哈
  public boolean wasCleared() {
    return (this.cleared && isEmpty());
  }
}