SpringMVC ModelAndView的用法使用详解

public class ModelAndView { 
 
  /** View instance or view name String */ 
  private Object view //该属性用来存储返回的视图信息
/** Model Map */ 
private ModelMap model;//<span style="color: rgb(0, 130, 0); font-family: Consolas, 'Courier New', Courier, mono, serif; line-height: 18px;">该属性用来存储处理后的结果数据</span> 
 
/** 
 * Indicates whether or not this instance has been cleared with a call to {@link #clear()}. 
 */ 
private boolean cleared = false; 
 
 
/** 
 * 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 <code>addObject</code>. 
 * @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 <code>addObject</code>. 
 * @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 <code>null</code>, but the 
 * model Map may be <code>null</code> if there is no model data. 
 */ 
public ModelAndView(String viewName, Map<String, ?> model) { 
  this.view = viewName; 
  if (model != null) { 
    getModelMap().addAllAttributes(model); 
  } 
} 
 
/** 
 * Creates new ModelAndView given a View object and a model. 
 * <emphasis>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</emphasis> 
 * @param view View object to render 
 * @param model Map of model names (Strings) to model objects 
 * (Objects). Model entries may not be <code>null</code>, but the 
 * model Map may be <code>null</code> if there is no model data. 
 */ 
public ModelAndView(View view, Map<String, ?> 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 <code>null</code> 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 <code>null</code> 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 <code>ModelAndView</code> 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. <code>true</code> 
 * 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 <code>null</code>. 
 * Called by DispatcherServlet for evaluation of the model. 
 */ 
protected Map<String, Object> getModelInternal() { 
  return this.model; 
} 
 
/** 
 * Return the underlying <code>ModelMap</code> instance (never <code>null</code>). 
 */ 
public ModelMap getModelMap() { 
  if (this.model == null) { 
    this.model = new ModelMap(); 
  } 
  return this.model; 
} 
 
/** 
 * Return the model map. Never returns <code>null</code>. 
 * To be called by application code for modifying the model. 
 */ 
public Map<String, Object> 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 <code>null</code>) 
 * @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 <code>null</code>) 
 * @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<String, ?> modelMap) { 
  getModelMap().addAllAttributes(modelMap); 
  return this; 
} 
 
 
/** 
 * Clear the state of this ModelAndView object. 
 * The object will be empty afterwards. 
 * <p>Can be used to suppress rendering of a given ModelAndView object 
 * in the <code>postHandle</code> 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 && CollectionUtils.isEmpty(this.model)); 
} 
 
/** 
 * 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. 
 * <p>Returns <code>false</code> if any additional state was added to the instance 
 * <strong>after</strong> the call to {@link #clear}. 
 * @see #clear() 
 */ 
public boolean wasCleared() { 
  return (this.cleared && isEmpty()); 
} 
 
 
/** 
 * Return diagnostic information about this model and view. 
 */ 
@Override 
public String toString() { 
  StringBuilder sb = new StringBuilder("ModelAndView: "); 
  if (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(); 
} 

package com.apress.springrecipes.court.web; 
... 
import org.springframework.web.servlet.ModelAndView; 
import org.springframework.web.servlet.mvc.AbstractController; 
public class WelcomeController extends AbstractController{ 
  public ModelAndView handleRequestInternal(HttpServletRequest request, 
    HttpServletResponse response)throws Exception{ 
    Date today = new Date(); 
    return new ModelAndView("welcome","today",today); 
  } 
}

package com.apress.springrecipes.court.web; 
... 
import org.springframework.web.servlet.ModelAndView; 
import org. springframework.web.servlet.mvc.AbstractController; 
public class ReservationQueryController extends AbstractController{ 
  ... 
  public ModelAndView handleRequestInternal(HttpServletRequest request, 
    HttpServletResponse response)throws Exception{ 
    ... 
    Map<String,Object> model = new HashMap<String,Object>(); 
    if(courtName != null){ 
      model.put("courtName",courtName); 
      model.put("reservations",reservationService.query(courtName)); 
    } 
    return new ModelAndView("reservationQuery",model); 
  } 
} 

package com.apress.springrecipes.court.web; 
... 
import org.springframework.ui.ModelMap; 
import org.springframework.web.servlet.ModelAndView; 
import org.springframework.web.servlet.mvc.AbstractController; 
public class ReservationQueryController extends AbstractController{ 
  ... 
  public ModelAndView handleRequestInternal(HttpServletRequest request, 
    HttpServletResponse response)throws Exception{ 
    ... 
    ModelMap model = new ModelMap(); 
    if(courtName != null){ 
      model.addAttribute("courtName",courtName); 
      model.addAttribute("reservations",reservationService.query(courtName)); 
    } 
    return new ModelAndView("reservationQuery",model); 
  } 
} 

addAttribute(String key,Object value); //modelMap的方法

public String xxxxmethod(String someparam,ModelMap model) 
{ 
   //省略方法处理逻辑若干 
   //将数据放置到ModelMap对象model中,第二个参数可以是任何java类型 
   model.addAttribute("key",someparam); 
   ...... 
   //返回跳转地址 
   return "path:handleok"; 
} 

ModelAndView(View view)

ModelAndView(View view, Map model)

ModelAndView(View view, String modelName, Object modelObject)

addObject(Object modelObject);
addObject(String modelName, Object modelObject);
addAllObjects(Map modelMap);

ModelAndView view = new ModelAndView("path:ok"); 

addObject(String key,Object value);