AJAX+JSF组件实现高性能的文件上载(4)

public void decode(FacesContext context， UIComponent component) {　UIFileUpload input = (UIFileUpload) component;　//检查是否这是一个上传进度请求，或是一个实际的上传请求.　ExternalContext extContext = context.getExternalContext();　Map parameterMap = extContext.getRequestParameterMap();　String clientId = input.getClientId(context);　Map requestMap = extContext.getRequestParameterMap();　if(requestMap.get(clientId) == null){return;//什么也不做，返回　}　if(parameterMap.containsKey(PROGRESS_REQUEST_PARAM_NAME)){//这是一个在该文件请求中的得到进度信息的请求.//得到该进度信息并把它生成为XMLHttpServletResponse response = (HttpServletResponse)context.getExternalContext().getResponse();//设置响应的头信息response.setContentType("text/xml");response.setHeader("Cache-Control"， "no-cache");try {　ResponseWriter writer = FacesUtils.setupResponseWriter(context);　writer.startElement("progress"， input);　writer.startElement("percentage"， input);　//从会话中获得当前进度百分数(由过滤器所设置).　Double progressCount = (Double)extContext.getSessionMap().　get("FileUpload.Progress." +input.getClientId(context)); 　if(progressCount != null){writer.writeText(progressCount， null);　}else{writer.writeText("1"， null);//我们还没有收到上传　}　writer.endElement("percentage");　writer.startElement("clientId"， input);　writer.writeText(input.getClientId(context)， null);　writer.endElement("clientId");　writer.endElement("progress");} catch(Exception e){　//做一些错误记录...}}else{　//正常的译码请求....

//正常的译码请求.if(requestMap.get(clientId).toString().equals("file")){try{　HttpServletRequest request = (HttpServletRequest)extContext.getRequest();　FileItem fileData = (FileItem)request.getAttribute(clientId);　if(fileData != null) input.setSubmittedValue(fileData);　//现在我们需要清除与该项相关的任何进度　extContext.getSessionMap().put("FileUpload.Progress." + input.getClientId(context)，new Double(100));}catch(Exception e){　throw new RuntimeException("不能处理文件上传" +" - 请配置过滤器."，e); }}

function refreshProgress(){ 　// 假定我们正在进入到阶段2.　document.getElementById('fileUpload1_stage1').style.display = 'none';　document.getElementById('fileUpload1_stage2').style.display = '';　document.getElementById('fileUpload1_stage3').style.display = 'none';　//创建AJAX寄送　AjaxRequest.post( 　{//指定正确的参数，以便//该组件在服务器端被正确处理 'parameters':{ 'uploadForm':'uploadForm'，'fileUpload1':'fileUpload1'，'jsf.component.UIFileUpload':'1'，'ajax.abortPhase':'4' } //Abort at Phase 4.//指定成功处理相应的回调方法.，'onSuccess':function(req) { var xml = req.responseXML;if( xml.getElementsByTagName('clientId').length == 0) { 　setTimeout('refreshProgress()'，200); return;} var clientId = xml.getElementsByTagName('clientId');clientId = clientId[0].firstChild.nodeValue + '_progressBar';//从XML获取百分比var percentage = xml.getElementsByTagName('percentage')[0].firstChild.nodeValue;var innerSpans =document.getElementById(clientId).getElementsByTagName('span');document.getElementById(clientId + 'label').innerHTML= Math.round(percentage) + '%';//基于当前进度，设置这些span的式样类。for(var i=0;i＜innerSpans.length;i++){　if(i ＜ percentage){innerSpans[i].className = 'active';　}else{innerSpans[i].className = 'passive'; 　}}//如果进度不是100，我们需要继续查询服务器以实现更新.if(percentage != 100){ 　setTimeout('refreshProgress()'，400);} else { 　//文件上传已经完成，我们现在需要把该组件送入到第3个阶段.　document.getElementById('fileUpload1_stage1').style.display = 'none';　document.getElementById('fileUpload1_stage2').style.display = 'none'; 　document.getElementById('fileUpload1_stage3').style.display = '';} 　}});}return builder.toString();