ModelAndView中的源码

以下是Spring Framework中ModelAndView类的源代码：

public class ModelAndView {

    @Nullable
    private Object view;

    private final Map<String, Object> model;

    public ModelAndView() {
        this.model = new LinkedHashMap<>();
    }

    public ModelAndView(@Nullable View view) {
        this.view = view;
        this.model = new LinkedHashMap<>();
    }

    public ModelAndView(@Nullable String viewName) {
        this.view = viewName;
        this.model = new LinkedHashMap<>();
    }

    public ModelAndView(@Nullable View view, @Nullable Map<String, ?> model) {
        this.view = view;
        this.model = (model != null ? new LinkedHashMap<>(model) : new LinkedHashMap<>());
    }

    public ModelAndView(@Nullable String viewName, @Nullable Map<String, ?> model) {
        this.view = viewName;
        this.model = (model != null ? new LinkedHashMap<>(model) : new LinkedHashMap<>());
    }

    public ModelAndView(@Nullable Object view, @Nullable String modelName, @Nullable Object modelObject) {
        this.view = view;
        this.model = new LinkedHashMap<>();
        addObject(modelName, modelObject);
    }

    public ModelAndView(@Nullable String viewName, @Nullable String modelName, @Nullable Object modelObject) {
        this.view = viewName;
        this.model = new LinkedHashMap<>();
        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 void setModel(Map<String, ?> model) {
        if (model != null) {
            this.model.putAll(model);
        }
    }

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

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

    public ModelAndView addObject(Object attributeValue) {
        Assert.notNull(attributeValue, "Model object must not be null");
        return addObject(BindingResult.MODEL_KEY_PREFIX + this.model.size(), attributeValue);
    }

    public ModelAndView addAllObjects(@Nullable Map<String, ?> modelMap) {
        if (modelMap != null) {
            modelMap.forEach(this::addObject);
        }
        return this;
    }

    public boolean isEmpty() {
        return this.model.isEmpty();
    }

    public int size() {
        return this.model.size();
    }

    @Nullable
    public Object get(String key) {
        return this.model.get(key);
    }

    public boolean containsKey(String key) {
        return this.model.containsKey(key);
    }

    public Set<String> keySet() {
        return this.model.keySet();
    }

    public ModelAndView clear() {
        this.view = null;
        this.model.clear();
        return this;
    }

    @Override
    public String toString() {
        return "ModelAndView [view=" + this.view + ", model=" + this.model + "]";
    }

}

该类主要用于封装视图和模型，其中视图可以是View类型的对象或视图的名称，模型则是一个Map类型的对象，用于存储视图所需的数据。除此之外，该类还提供了一些方法来设置和获取视图和模型，以及添加、删除、清空模型数据等。