[webwork] 重定向

相比我们大家对重定向不是很陌生，在sevlet中可以使用如下两种方法重定向：

 产生一个新的HTTP请求的的重定向：

response.sendRedirect(url);

 

带着前一个HTTP请求参数的forward：

　RequestDispatcher rd = null;　rd = sc.getRequestDispatcher(url);　rd.forward(request, response);

那么如何在webwork框架中进行上述两种重定向呢？

 

首先我们来看下第一种重定向：

在webwork 中有两种result 用于第一种的重定向，分别是：

com.opensymphony.webwork.dispatcher.ServletActionRedirectResultcom.opensymphony.webwork.dispatcher.ServletRedirectResult

（下面我们把上述 ServletRedirectResult 简称为 redirect ,ServletActionRedirectResult 简称为 redirectAction）

 

那么这两个有什么区别呢？

首先看下 redirect 的源代码（这里只展现执行跳转的代码）

ActionContext ctx = invocation.getInvocationContext(); HttpServletRequest request = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST); HttpServletResponse response = (HttpServletResponse) ctx.get(ServletActionContext.HTTP_RESPONSE); if (isPathUrl(finalLocation)) { if (!finalLocation.startsWith("/")) { String namespace = ActionMapperFactory.getMapper().getMapping(request).getNamespace(); if ((namespace != null) && (namespace.length() > 0) && (!"/".equals(namespace))) { finalLocation = namespace + "/" + finalLocation; } else { finalLocation = "/" + finalLocation; } } // if the URL's are relative to the servlet context, append the servlet context path if (prependServletContext && (request.getContextPath() != null) && (request.getContextPath().length() > 0)) { finalLocation = request.getContextPath() + finalLocation; } finalLocation = response.encodeRedirectURL(finalLocation); } if (log.isDebugEnabled()) { log.debug("Redirecting to finalLocation " + finalLocation); } response.sendRedirect(finalLocation);

 

这段代码先根据参数拼装URL，然后在sendRedirect 到新的url。

 

首先一点 从类的关系上来看 redirectAction 是继承自 redirect的

接着我们来看下 redirectAction 的源代码，（同样也是展现跳转的源代码）

actionName = conditionalParse(actionName, invocation); if (namespace == null) { namespace = invocation.getProxy().getNamespace(); } else { namespace = conditionalParse(namespace, invocation); } if (method == null) { method = ""; } else { method = conditionalParse(method, invocation); } Map requestParameters = new HashMap(); ResultConfig resultConfig = (ResultConfig) invocation.getProxy().getConfig().getResults().get( invocation.getResultCode()); Map resultConfigParams = resultConfig.getParams(); for (Iterator i = resultConfigParams.entrySet().iterator(); i.hasNext(); ) { Map.Entry e = (Map.Entry) i.next(); if (! prohibitedResultParam.contains(e.getKey())) { requestParameters.put(e.getKey().toString(), e.getValue() == null ? "": conditionalParse(e.getValue().toString(), invocation)); } } ActionMapper mapper = ActionMapperFactory.getMapper(); StringBuffer tmpLocation = new StringBuffer(mapper.getUriFromActionMapping(new ActionMapping(actionName, namespace, method, null))); UrlHelper.buildParametersString(requestParameters, tmpLocation, "&"); location = tmpLocation.toString(); super.execute(invocation);

很明显的可以看出这段代码并没有使用任何servlet的重定向，而是简单的把上个请求的参数通过配置

的取舍加到下个invocation中，去请求了另外一个action

 

所以webwork 官方也建议使用redirectAction ,见 （It is strongly recommended that if you are redirecting to another action, you use this result rather than thestandard redirect result.）

webwork 官方关于redirectAction

 

 

关于第二种重定向，webwork中用下面这个类来实现:

com.opensymphony.webwork.dispatcher.ServletDispatcherResult

 

来看下执行跳转的代码：

if (log.isDebugEnabled()) { log.debug("Forwarding to location " + finalLocation); } PageContext pageContext = ServletActionContext.getPageContext(); if (pageContext != null) { pageContext.include(finalLocation); } else { HttpServletRequest request = ServletActionContext.getRequest(); HttpServletResponse response = ServletActionContext.getResponse(); RequestDispatcher dispatcher = request.getRequestDispatcher(finalLocation); // if the view doesn't exist, let's do a 404 if (dispatcher == null) { response.sendError(404, "result '" + finalLocation + "' not found"); return; } // If we're included, then include the view // Otherwise do forward // This allow the page to, for example, set content type if (!response.isCommitted() && (request.getAttribute("javax.servlet.include.servlet_path") == null)) { request.setAttribute("webwork.view_uri", finalLocation); request.setAttribute("webwork.request_uri", request.getRequestURI()); dispatcher.forward(request, response); } else { dispatcher.include(request, response); } }