Spring MVC自定义范围bean

我想创建自己的自定义范围bean，它将使用HTTP会话（一种Flash范围）。

根据Spring Manual我需要实现org.springframework.beans.factory.config.Scope接口

public class CustomScope implements Scope { @Override public Object get(String arg0, ObjectFactory arg1) { // TODO Auto-generated method stub return null; } @Override public String getConversationId() { // TODO Auto-generated method stub return null; } @Override public void registerDestructionCallback(String arg0, Runnable arg1) { // TODO Auto-generated method stub } @Override public Object remove(String arg0) { // TODO Auto-generated method stub return null; } @Override public Object resolveContextualObject(String arg0) { // TODO Auto-generated method stub return null; } } 

我的问题是如何在这个bean里面获得HTTP会话？ 据我所知，如果我在ServletContext范围内创建bean，我会实现ServletContextAware接口。

请帮忙 ：）

Answer 1

我希望它对将来有用，所以我想分享一下。

我对它进行了一些研究并发现遗憾的是，不可能获得Spring MVC的HTTP Session。

我的目的是使用PRG模式为我的Spring MVC控制器实现Flash Scope。

在Spring Forum中进行更多研究我已经找到了使用HandlerInterceptor进行研究的方法。

 import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.util.*; import java.util.Map.Entry; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; 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 modelFlashScopeMap = null; for (Iterator> iterator = ((Map) modelAndView.getModel()).entrySet() .iterator(); iterator.hasNext();) { Entry 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(); } 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; } } 

现在MultiScopeModelMap.java

 import java.io.Serializable; import java.util.Collection; import java.util.HashMap; import java.util.LinkedList; import java.util.Map; import java.util.Set; import org.apache.commons.collections.map.CompositeMap; import org.apache.commons.collections.map.CompositeMap.MapMutator; 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 

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，用法非常简单：

 ${flashScope.message} 

此外，您需要将FlashScopeInterceptor类配置为拦截器。

Answer 2

我建议看一下org.springframework.web.context.request.SessionScope的源代码。 这个范围必须解决同样的问题。

看起来他们使用： RequestContextHolder.currentRequestAttributes().getSessionId()

Answer 3

您可以使用Spring MVC中的作用域类方法中的下一个代码来访问会话属性（在3.2中工作）：

 RequestAttributes attributes = RequestContextHolder.currentRequestAttributes(); attributes.getAttribute("some key", NativeWebRequest.SCOPE_SESSION); attributes.setAttribute("some key", YouObject, NativeWebRequest.SCOPE_SESSION); 

RequestAttributes实现（ServletRequestAttributes）在内部将调用当前会话对象上的set / getAttribute（）方法。