Model是个接口，实现类是
public class ExtendedModelMap extends ModelMap implements Model
ModelMap继承于
public class ModelMap extends LinkedHashMap<String, Object>
ModelAndView 这个类里边包含一个ModelMap的实例,除此之外还有一个View、

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

@GetMapping(value = "url")
public String toAddPage(ModelMap modelMap, ModelAndView modelAndView, Model model){
    System.out.println(model.getClass());
    System.out.println("toAddPage" + modelMap.get("param"));
    return "url/details";
}
方法参数里边Model有spring mvc创建的model，实现的是BindingAwareModelMap 
而BindingAwareModelMap 继承于ExtendedModelMap
public class BindingAwareModelMap extends ExtendedModelMap
BindingAwareModelMap除了继承自ExtendedModelMap父类的方法，还实现了三个方法
public Object put(String key, Object value)
public void putAll(Map<? extends String, ?> map) 
private void removeBindingResultIfNecessary(Object key, Object value) 
put和putAll方法比起父类自带的addAttribute、addAllAttributes好像是多了一个移除重复key的一个功能

spring里new的是BindingAwareModelMap 这个继承与 ExtendedModelMap ExtendedModelMap继承与ModelMap 实现Model ， ModelMap 继承与LinkedHashMap来放数据 实现model接口就是给放数据的这个LinkedHashMap增加了几个放数据的方法

Model是一个接口

源码如下

public interface Model {
    Model addAttribute(String var1, @Nullable Object var2);

    Model addAttribute(Object var1);

    Model addAllAttributes(Collection<?> var1);

    Model addAllAttributes(Map<String, ?> var1);

    Model mergeAttributes(Map<String, ?> var1);

    boolean containsAttribute(String var1);

    Map<String, Object> asMap();
}

ModelMap

public class ModelMap extends LinkedHashMap<String, Object> {
    public ModelMap() { }

    public ModelMap(String attributeName, Object attributeValue) {
        this.addAttribute(attributeName, attributeValue);
    }

    public ModelMap(Object attributeValue) {
        this.addAttribute(attributeValue);
    }

    public ModelMap addAttribute(String attributeName, @Nullable Object attributeValue) {
        Assert.notNull(attributeName, "Model attribute name must not be null");
        this.put(attributeName, attributeValue);
        return this;
    }

    public ModelMap addAttribute(Object attributeValue) {
        Assert.notNull(attributeValue, "Model object must not be null");
        return attributeValue instanceof Collection && ((Collection)attributeValue).isEmpty() ? this : this.addAttribute(Conventions.getVariableName(attributeValue), attributeValue);
    }

    public ModelMap addAllAttributes(@Nullable Collection<?> attributeValues) {
        if (attributeValues != null) {
            Iterator var2 = attributeValues.iterator();

            while(var2.hasNext()) {
                Object attributeValue = var2.next();
                this.addAttribute(attributeValue);
            }
        }

        return this;
    }

    public ModelMap addAllAttributes(@Nullable Map<String, ?> attributes) {
        if (attributes != null) {
            this.putAll(attributes);
        }

        return this;
    }

    public ModelMap mergeAttributes(@Nullable Map<String, ?> attributes) {
        if (attributes != null) {
            attributes.forEach((key, value) -> {
                if (!this.containsKey(key)) {
                    this.put(key, value);
                }

            });
        }

        return this;
    }

    public boolean containsAttribute(String attributeName) {
        return this.containsKey(attributeName);
    }
}

ModelAndView

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

    public ModelAndView(View view, @Nullable 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(@Nullable String viewName, @Nullable Map<String, ?> model, @Nullable 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(@Nullable String viewName) {
        this.view = viewName;
    }

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

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

    @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;
    }

    @Nullable
    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(@Nullable HttpStatus status) {
        this.status = status;
    }

    @Nullable
    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(@Nullable 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();
    }
}