spring mvc为何不推荐使用addObject方法？

Question

我用的spring mvc开发的值钱项目使用的ModelAndView的方式返回的参数，和映射地址！

现在开发使用了spring 2.5用上了批注！返回值的传递用ModelMap。
为何原来的ModelAndView 支持addObject，但是ModelMap的这个方法就花了个横杠？
我知道是过期的意思，但是我想知道处于何目的！

（以后要是遇到同样问题如何去找，答案，希望深入了解下！）
[b]问题补充：[/b]
确实有,希望有人能解答一下！

Answer 1

读了下源代码,确实没有.
不知道你的spring到底是哪个版本.
下面是2.5.6的ModelAndView的代码:
/*

• Copyright 2002-2006 the original author or authors. *
• Licensed under the Apache License, Version 2.0 (the "License");
• you may not use this file except in compliance with the License.
• You may obtain a copy of the License at *
• http://www.apache.org/licenses/LICENSE-2.0 *
• Unless required by applicable law or agreed to in writing, software
• distributed under the License is distributed on an "AS IS" BASIS,
• WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
• See the License for the specific language governing permissions and
• limitations under the License. */

package org.springframework.web.servlet;

import java.util.Map;

import org.springframework.ui.ModelMap;

/**

• Holder for both Model and View in the web MVC framework.
• Note that these are entirely distinct. This class merely holds
• both to make it possible for a controller to return both model
• and view in a single return value. *

• Represents a model and view returned by a handler, to be resolved

• by a DispatcherServlet. The view can take the form of a String
• view name which will need to be resolved by a ViewResolver object;
• alternatively a View object can be specified directly. The model
• is a Map, allowing the use of multiple objects keyed by name. *
• @author Rod Johnson
• @author Juergen Hoeller
• @author Rob Harrop
• @see DispatcherServlet
• @see ViewResolver
• @see HandlerAdapter#handle

• @see org.springframework.web.servlet.mvc.Controller#handleRequest
  */
  public class ModelAndView {

  /** View instance or view name String */
  private Object view;

  /** Model Map */
  private ModelMap model;

  /**

  • Indicates whether or not this instance has been cleared with a call to {@link #clear()}. */ private boolean cleared;

  /**

  • Default constructor for bean-style usage: populating bean
  • properties instead of passing in constructor arguments.
  • @see #setView(View)
  • @see #setViewName(String) */ public ModelAndView() { }

  /**

  • Convenient constructor when there is no model data to expose.
  • Can also be used in conjunction with addObject.
  • @param viewName name of the View to render, to be resolved
  • by the DispatcherServlet's ViewResolver
  • @see #addObject */ public ModelAndView(String viewName) { this.view = viewName; }

  /**

  • Convenient constructor when there is no model data to expose.
  • Can also be used in conjunction with addObject.
  • @param view View object to render
  • @see #addObject */ public ModelAndView(View view) { this.view = view; }

  /**

  • Creates new ModelAndView given a view name and a model.
  • @param viewName name of the View to render, to be resolved
  • by the DispatcherServlet's ViewResolver
  • @param model Map of model names (Strings) to model objects
  • (Objects). Model entries may not be null, but the
  • model Map may be null if there is no model data. */ public ModelAndView(String viewName, Map model) { this.view = viewName; if (model != null) { getModelMap().addAllAttributes(model); } }

  /**

  • Creates new ModelAndView given a View object and a model.
  • Note: the supplied model data is copied into the internal
  • storage of this class. You should not consider to modify the supplied
  • Map after supplying it to this class
  • @param view View object to render
  • @param model Map of model names (Strings) to model objects
  • (Objects). Model entries may not be null, but the
  • model Map may be null if there is no model data. */ public ModelAndView(View view, Map model) { this.view = view; if (model != null) { getModelMap().addAllAttributes(model); } }

  /**

  • Convenient constructor to take a single model object.
  • @param viewName name of the View to render, to be resolved
  • by the DispatcherServlet's ViewResolver
  • @param modelName name of the single entry in the model
  • @param modelObject the single model object */ public ModelAndView(String viewName, String modelName, Object modelObject) { this.view = viewName; addObject(modelName, modelObject); }

  /**

  • Convenient constructor to take a single model object.
  • @param view View object to render
  • @param modelName name of the single entry in the model
  • @param modelObject the single model object */ public ModelAndView(View view, String modelName, Object modelObject) { this.view = view; addObject(modelName, modelObject); }

  /**

  • Set a view name for this ModelAndView, to be resolved by the
  • DispatcherServlet via a ViewResolver. Will override any
  • pre-existing view name or View. */ public void setViewName(String viewName) { this.view = viewName; }

  /**

  • Return the view name to be resolved by the DispatcherServlet
  • via a ViewResolver, or null if we are using a View object. */ public String getViewName() { return (this.view instanceof String ? (String) this.view : null); }

  /**

  • Set a View object for this ModelAndView. Will override any
  • pre-existing view name or View. */ public void setView(View view) { this.view = view; }

  /**

  • Return the View object, or null if we are using a view name
  • to be resolved by the DispatcherServlet via a ViewResolver. */ public View getView() { return (this.view instanceof View ? (View) this.view : null); }

  /**

  • Indicate whether or not this ModelAndView has a view, either
  • as a view name or as a direct {@link View} instance. */ public boolean hasView() { return (this.view != null); }

  /**

  • Return whether we use a view reference, i.e. true
  • if the view has been specified via a name to be resolved by the
  • DispatcherServlet via a ViewResolver. */ public boolean isReference() { return (this.view instanceof String); }

  /**

  • Return the model map. May return null.
  • Called by DispatcherServlet for evaluation of the model. */ protected Map getModelInternal() { return this.model; }

  /**

  • Return the underlying ModelMap instance (never null). */ public ModelMap getModelMap() { if (this.model == null) { this.model = new ModelMap(); } return this.model; }

  /**

  • Return the model map. Never returns null.
  • To be called by application code for modifying the model. */ public Map getModel() { return getModelMap(); }

  /**

  • Add an attribute to the model.
  • @param attributeName name of the object to add to the model
  • @param attributeValue object to add to the model (never null)
  • @see ModelMap#addAttribute(String, Object)
  • @see #getModelMap() */ public ModelAndView addObject(String attributeName, Object attributeValue) { getModelMap().addAttribute(attributeName, attributeValue); return this; }

  /**

  • Add an attribute to the model using parameter name generation.
  • @param attributeValue the object to add to the model (never null)
  • @see ModelMap#addAttribute(Object)
  • @see #getModelMap() */ public ModelAndView addObject(Object attributeValue) { getModelMap().addAttribute(attributeValue); return this; }

  /**

  • Add all attributes contained in the provided Map to the model.
  • @param modelMap a Map of attributeName -> attributeValue pairs
  • @see ModelMap#addAllAttributes(Map)
  • @see #getModelMap() */ public ModelAndView addAllObjects(Map modelMap) { getModelMap().addAllAttributes(modelMap); return this; }

  /**

  • Clear the state of this ModelAndView object.
  • The object will be empty afterwards.

  • Can be used to suppress rendering of a given ModelAndView object

  • in the postHandle method of a HandlerInterceptor.
  • @see #isEmpty()
  • @see HandlerInterceptor#postHandle */ public void clear() { this.view = null; this.model = null; this.cleared = true; }

  /**

  • Return whether this ModelAndView object is empty
  • i.e. whether it does not hold any view and does not contain a model. */ public boolean isEmpty() { return (this.view == null && this.model == null); }

  /**

  • Return whether this ModelAndView object is empty as a result of a call to {@link #clear}
  • i.e. whether it does not hold any view and does not contain a model.
  • Returns false if any additional state was added to the instance
  • after the call to {@link #clear}.
  • @see #clear() */ public boolean wasCleared() { return (this.cleared && isEmpty()); }

  /**

  • Return diagnostic information about this model and view. */ public String toString() { StringBuffer buf = new StringBuffer("ModelAndView: "); if (isReference()) { buf.append("reference to view with name '").append(this.view).append("'"); } else { buf.append("materialized View is [").append(this.view).append(']'); } buf.append("; model is ").append(this.model); return buf.toString(); } }