spring如何将值从一个页面传递给控制器​​?

时间:2011-06-24 07:49:29

标签: model-view-controller spring

我正在开发一个spring mvc应用程序。我只是想做以下事情,

当用户点击链接时,我只想将该页面中的一些值传递给该链接的目标控制器。

AbstractCommandController对此有用吗?

除了使用会话属性之外还有其他方法吗?

1 个答案:

答案 0 :(得分:0)

您可以通过以下方式之一进行操作:

1)提交表格。

2)将其作为参数发送到您的网址。

3)为您的应用程序创建cusom flash范围: 你可以在这里阅读更多相关信息:http://goo.gl/nQaQh

在Spring MVC中没有Flash Bean范围,因此您可以将其作为Interceptor:

以下是使用

的简单代码
public class FlashScopeInterceptor implements HandlerInterceptor {

    public static final String DEFAULT_ATTRIBUTE_NAME = "flashScope";
    public static final String DEFAULT_SESSION_ATTRIBUTE_NAME = FlashScopeInterceptor.class.getName();
    public static final int DEFAULT_RETENTION_COUNT = 2;

    private String sessionAttributeName = DEFAULT_SESSION_ATTRIBUTE_NAME;
    private String attributeName = DEFAULT_ATTRIBUTE_NAME;
    private int retentionCount = DEFAULT_RETENTION_COUNT;

    /**
     * Unbinds current flashScope from session. Rolls request's flashScope to
     * the next scope. Binds request's flashScope, if not empty, to the session.
     * 
     */

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        if (request.getSession( false ) != null)
        {
            request.getSession().removeAttribute( this.sessionAttributeName );
        }
        Object requestAttribute = request.getAttribute( this.attributeName );
        if (requestAttribute instanceof MultiScopeModelMap)
        {
            MultiScopeModelMap attributes = (MultiScopeModelMap) requestAttribute;
            if (!attributes.isEmpty())
            {
                attributes.next();
                if (!attributes.isEmpty())
                {
                    request.getSession( true ).setAttribute( this.sessionAttributeName, attributes );
                }
            }
        }
    }

    /**
     * merge modelAndView.model['flashScope'] to current flashScope
     */
    @Override
    public void postHandle( HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        if (modelAndView != null)
        {
            Map<String, Object> modelFlashScopeMap = null;
            for (Iterator<Entry<String, Object>> iterator = ((Map<String, Object>) modelAndView.getModel()).entrySet()
                    .iterator(); iterator.hasNext();)
            {
                Entry<String, Object> entry = iterator.next();
                if (this.attributeName.equals( entry.getKey() ) && entry.getValue() instanceof Map)
                {
                    if (modelFlashScopeMap == null)
                    {
                        modelFlashScopeMap = (Map) entry.getValue();
                    }
                    else
                    {
                        modelFlashScopeMap.putAll( (Map) entry.getValue() );
                    }
                    iterator.remove();
                }
                else if (entry.getKey().startsWith( this.attributeName + "." ))
                {
                    String key = entry.getKey().substring( this.attributeName.length() + 1 );
                    if (modelFlashScopeMap == null)
                    {
                        modelFlashScopeMap = new HashMap<String, Object>();
                    }
                    modelFlashScopeMap.put( key, entry.getValue() );
                    iterator.remove();
                }
            }
            if (modelFlashScopeMap != null)
            {
                MultiScopeModelMap flashScopeMap;
                if (request.getAttribute( this.attributeName ) instanceof MultiScopeModelMap)
                {
                    flashScopeMap = (MultiScopeModelMap) request.getAttribute( this.attributeName );
                }
                else
                {
                    flashScopeMap = new MultiScopeModelMap( this.retentionCount );
                }
                flashScopeMap.putAll( modelFlashScopeMap );
                request.setAttribute( this.attributeName, flashScopeMap );
            }
        }
    }

    /**
     * binds session flashScope to current session, if not empty. Otherwise cleans up empty
     * flashScope
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        HttpSession session = request.getSession( false );
        if (session != null)
        {
            Object sessionAttribute = session.getAttribute( this.sessionAttributeName );
            if (sessionAttribute instanceof MultiScopeModelMap)
            {
                MultiScopeModelMap flashScope = (MultiScopeModelMap) sessionAttribute;
                if (flashScope.isEmpty())
                {
                    session.removeAttribute( this.sessionAttributeName );
                }
                else
                {
                    request.setAttribute( this.attributeName, flashScope );
                }
            }
        }
        return true;
    }
}

然后是MultiScopeModelMap

public class MultiScopeModelMap extends CompositeMap implements Serializable, MapMutator
{
    public MultiScopeModelMap(int num)
    {
        super();
        setMutator( this );
        for(int i = 0; i < num; ++i)
        {
            addComposited( new HashMap() );
        }
    }

    /** Shadows composite map. */
    private final LinkedList<Map> maps = new LinkedList<Map>();

    @Override
    public synchronized void addComposited( Map map ) throws IllegalArgumentException
    {
        super.addComposited( map );
        this.maps.addLast( map );
    }

    @Override
    public synchronized Map removeComposited( Map map )
    {
        Map removed = super.removeComposited( map );
        this.maps.remove( map );
        return removed;
    }
    /** 
     * Starts a new scope. 
     * All items added in the session before the previous session are removed.
     * All items added in the previous scope are still retrievable and removable.
     */ 
    public void next()
    {
        removeComposited( this.maps.getFirst() );
        addComposited( new HashMap() );
    }

    public Object put( CompositeMap map, Map[] composited, Object key, Object value )
    {
        if(composited.length < 1)
        {
            throw new UnsupportedOperationException("No composites to add elements to");
        }
        Object result = map.get( key );
        if(result != null)
        {
            map.remove( key );
        }
        composited[composited.length-1].put( key, value );
        return result;
    }

    public void putAll( CompositeMap map, Map[] composited, Map mapToAdd )
    {
        for(Entry entry: (Set<Entry>)mapToAdd.entrySet())
        {
            put(map, composited, entry.getKey(), entry.getValue());
        }
    }

    public void resolveCollision( CompositeMap composite, Map existing, Map added, Collection intersect )
    {
        existing.keySet().removeAll( intersect );       
    }

    @Override
    public String toString()
    {
        return new HashMap(this).toString();
    }   
}

现在在xml:

中配置它
<bean id="flashScopeInterceptor" class="com.vanilla.scopes.FlashScopeInterceptor" />
<bean id="handlerMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
  <property name="interceptors">
    <list><ref bean="flashScopeInterceptor"/></list>
  </property>
</bean>

用法:

@RequestMapping(value="/login.do", method=RequestMethod.POST)
    public ModelAndView login(@Valid User user){
        ModelAndView mv = new ModelAndView("redirect:result.html");
        if (authService.authenticate(user.getUserName(), user.getPassword()))
            mv.addObject("flashScope.message", "Success");
        //else
            mv.addObject("flashScope.message", "Login Failed");
        return mv;
    }

@RequestMapping(value ="/result.html", method=RequestMethod.GET)
    public ModelAndView result(){
        ModelAndView mv = new ModelAndView("login/loginAction");
        return mv;
    }

在JSP中,使用非常简单:

${flashScope.message}