struts2上傳文件添加進度條

　　給文件上傳添加進度條，整了兩天終於成功了。

　　想要添加一個上傳的進度條，經過分析，應該是須要不斷的去訪問服務器，詢問上傳文件的大小。經過已上傳文件的大小，

和上傳文件的總長度來評估上傳的進度。

　　實現監聽器ProgressListener接口，能夠實時獲取上傳文件的長度。

public class FileUploadListener implements ProgressListener{
     private HttpSession session;  
               
    public FileUploadListener(HttpServletRequest request) {  
           session = request.getSession();  
           FileState state = new FileState();  // 自定義FileState POJO類，儲存狀態信息
           session.setAttribute("state", state);  
             }  
    @Override
    public void update(long readedBytes, long totalBytes, int currentItem) {
        // TODO Auto-generated method stub
         //System.out.println("update:"+readedBytes+";"+totalBytes+";"+currentItem);  
                          
                 FileState state = (FileState) session.getAttribute("state");  
                state.setReadedBytes(readedBytes);  // 已讀數據的長度
                state.setTotalBytes(totalBytes);  // 文件總長度
                state.setCurrentItem(currentItem);  // 正在保存第幾個文件
    }

}

FileState類

public class FileState {
    private long readedBytes = 0L; // 已經上傳的字節數，單位：字節
    private long totalBytes = 0L; // 全部文件的總長度，單位：字節
    private int currentItem = 0; // 正在上傳第幾個文件
    private long startTime=System.currentTimeMillis(); //開始上傳的時間，用於計算上傳的速度
    
    public long getStartTime() {
        return startTime;
    }
    public void setStartTime(long startTime) {
        this.startTime = startTime;
    }
    public long getReadedBytes() {
        return readedBytes;
    }
    public void setReadedBytes(long readedBytes) {
        this.readedBytes = readedBytes;
    }
    public long getTotalBytes() {
        return totalBytes;
    }
    public void setTotalBytes(long totalBytes) {
        this.totalBytes = totalBytes;
    }
    public int getCurrentItem() {
        return currentItem;
    }
    public void setCurrentItem(int currentItem) {
        this.currentItem = currentItem;
    }
    
}

 把監聽器FileUploadListener 添加到MyJakartaMultiPartRequest類中。MyJakartaMultiPartRequest類是Struts2源碼中的JakartaMultiPartRequest類。

在此類中添加進度監聽器，並覆蓋此類。

  private List<FileItem> parseRequest(HttpServletRequest servletRequest, String saveDir) throws FileUploadException {
        /* FileState fileState=new FileState();
         servletRequest.getSession().setAttribute("state", fileState);*/
        DiskFileItemFactory fac = createDiskFileItemFactory(saveDir);
        ServletFileUpload upload = new ServletFileUpload(fac);
        upload.setSizeMax(maxSize);
        // add  設置進度監聽器
       
        upload.setProgressListener(new FileUploadListener(servletRequest));
        
        // end 
        return upload.parseRequest(createRequestContext(servletRequest));
    }

在xml中配置

 <!-- 配置自定義文件類myrefactor，繼承MultiPartRequest重寫 -->
<bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="myrefactor" 
         class="com.service.MyJakartaMultiPartRequest" scope="default" optional="true" />

action

public class FileProgressAction {
    /**
           * 顯示文件上傳的進度
           */
          public String execute(){
             HttpServletResponse response= ServletActionContext.getResponse();
              response.setHeader("Cache-Control", "no-store"); //禁止瀏覽器緩存
              response.setHeader("Pragrma", "no-cache"); //禁止瀏覽器緩存
              response.setDateHeader("Expires", 0); //禁止瀏覽器緩存
              Map session=ActionContext.getContext().getSession();
              PrintWriter out = null;
            try {
                out = response.getWriter();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
              FileState status = (FileState)session.get("state");
              if(status == null){
                 //renderText("error");
                 return null;
             }
             
             long startTime = status.getStartTime(); //上傳開始時間
             long currentTime = System.currentTimeMillis(); //如今時間
             long time = (currentTime - startTime)/ 1000 + 1; //已傳輸的時間 單位:s
             
             //傳輸速度單位:byte/s
             double velocity = ((double)status.getReadedBytes()) / (double)time;
             //估計總時間
             double totalTime = status.getTotalBytes();
             //估計剩餘時間
             double timeLeft = totalTime - time;
             //已經完成的百分比
             int percent = (int)(100 * (double)status.getReadedBytes() / (double)status.getTotalBytes());
             //已經完成數單位:m
             double length = ((double) status.getReadedBytes())/1024/1024;
             //總長度 單位:m
             double totalLength = ((double) status.getTotalBytes())/1024/1024; 
             
             JSONObject json = new JSONObject();
             json.put("percent", percent);
             json.put("length", length);
             json.put("totalLength", totalLength);
             json.put("velocity", velocity);
             json.put("time", time);
             json.put("totalTime", totalTime);
             json.put("timeLeft", timeLeft);
             json.put("fileNumber", status.getCurrentItem());
            
            // System.out.println(json.toString());
             out.print(json.toString());
             return null;
             
         }
}

js

 var finished = true; //上傳是否結束
               function showStatus(){
                   finished = false;
                  /*$('#progressBarItem').attr('width','1%');*/
                   
                  setTimeout('callback()',100);
             }
              
              function callback(){
                  if(finished) return;
                  var url = 'fileProgressAction';
                   $.get(url,function(dataSrc){
                       var dataS=eval("("+dataSrc+")");
                       $('#progressBarItem').html("("+dataS.percent+"%"+")");
                       //alert(dataS.percent);
                   });
                  
                  setTimeout('callback()',100);
              }

jsp

<div style="width: 86px;float: left;margin-top: 15px;margin-left: 5px;">        
     
     <form action="filesUpload" method="post" enctype="multipart/form-data" style="margin-top: 16px;" onsubmit="return subClick()" >      
        <a href="javascript:;" class="file">
             <img alt="tip" src="images/upload.png" style="width: 55px;">
             <input type="file" name="myFile" multiple="multiple" id="myFile" value="0" onchange="uplaodfileOnChange(this)">
       </a>
  
            <input type="submit" value="上傳文件" style="margin-top: 3px;display: none;"  id="sub" class="a-upload" onclick="wait()" /> 

        <div id="fileDiv"></div>
        <div style="margin-left: 7px;margin-top: 3px;width: 300px;" id="messageDiv" class="tip">${message} </div>                    
        <%-- <span class="tip" id="perMessage"> ${request.perMessage} </span>       --%> 
 </form>
    <div id="error" class="tip" style="width: 1024px;"> <s:fielderror> </s:fielderror></div>
</div>