struts2上传文件添加进度条

　　给文件上传添加进度条，整了两天终于成功了。

　　想要添加一个上传的进度条，通过分析，应该是需要不断的去访问服务器，询问上传文件的大小。通过已上传文件的大小，

和上传文件的总长度来评估上传的进度。

　　实现监听器ProgressListener接口，可以实时获取上传文件的长度。

public class FileUploadListener implements ProgressListener{
     private HttpSession session;  
               
    public FileUploadListener(HttpServletRequest request) {  
           session = request.getSession();  
           FileState state = new FileState();  // 自定义FileState POJO类，储存状态信息
           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);  // 已读数据的长度
                state.setTotalBytes(totalBytes);  // 文件总长度
                state.setCurrentItem(currentItem);  // 正在保存第几个文件
    }

}

FileState类

public class FileState {
    private long readedBytes = 0L; // 已经上传的字节数，单位：字节
    private long totalBytes = 0L; // 所有文件的总长度，单位：字节
    private int currentItem = 0; // 正在上传第几个文件
    private long startTime=System.currentTimeMillis(); //开始上传的时间，用于计算上传的速度
    
    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;
    }
    
}

 把监听器FileUploadListener 添加到MyJakartaMultiPartRequest类中。MyJakartaMultiPartRequest类是Struts2源码中的JakartaMultiPartRequest类。

在此类中添加进度监听器，并覆盖此类。

  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  设置进度监听器
       
        upload.setProgressListener(new FileUploadListener(servletRequest));
        
        // end 
        return upload.parseRequest(createRequestContext(servletRequest));
    }

在xml中配置

 <!-- 配置自定义文件类myrefactor，继承MultiPartRequest重写 -->
<bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="myrefactor" 
         class="com.service.MyJakartaMultiPartRequest" scope="default" optional="true" />

action

public class FileProgressAction {
    /**
           * 显示文件上传的进度
           */
          public String execute(){
             HttpServletResponse response= ServletActionContext.getResponse();
              response.setHeader("Cache-Control", "no-store"); //禁止浏览器缓存
              response.setHeader("Pragrma", "no-cache"); //禁止浏览器缓存
              response.setDateHeader("Expires", 0); //禁止浏览器缓存
              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(); //上传开始时间
             long currentTime = System.currentTimeMillis(); //现在时间
             long time = (currentTime - startTime)/ 1000 + 1; //已传输的时间 单位:s
             
             //传输速度单位:byte/s
             double velocity = ((double)status.getReadedBytes()) / (double)time;
             //估计总时间
             double totalTime = status.getTotalBytes();
             //估计剩余时间
             double timeLeft = totalTime - time;
             //已经完成的百分比
             int percent = (int)(100 * (double)status.getReadedBytes() / (double)status.getTotalBytes());
             //已经完成数单位:m
             double length = ((double) status.getReadedBytes())/1024/1024;
             //总长度 单位: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; //上传是否结束
               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=" 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=" 55px;">
             <input type="file" name="myFile" multiple="multiple" id="myFile" value="0" onchange="uplaodfileOnChange(this)">
       </a>
  
            <input type="submit" value="上传文件" 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; 300px;" id="messageDiv" class="tip">${message} </div>                    
        <%-- <span class="tip" id="perMessage"> ${request.perMessage} </span>       --%> 
 </form>
    <div id="error" class="tip" style=" 1024px;"> <s:fielderror> </s:fielderror></div>
</div>