一. struts2讀取進度原理分析(作為草稿存了好久，剛剛發(fā)布出來......)
1. 在strut2中控制文件上傳信息的類是實現(xiàn)MultiPartRequest接口的JakartaMultiPartRequest
其實第一次看到源文件時我打了個退堂鼓，因為覺得內(nèi)容太長了，不想看。冷靜下來將思路理順，將分開的各個方法還原到一個方方中中，發(fā)現(xiàn)還是很好理解的：
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@Override public void parse(HttpServletRequest request, String saveDir) throws IOException { setLocale(request); //規(guī)定了File文件的格式（如文件名必須是xxFileName，文件類型xxContentType），并定義了File的保存路徑 DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory);//處理文件上傳的servlet upload.setProgressListener(new FileUploadProgressListener(request)); //為文件上傳添加監(jiān)聽 factory.setSizeThreshold(0); //if (saveDir != null factory.setRepository(new File(saveDir));//臨時路徑 } try { upload.setSizeMax(maxSize); List items = upload.parseRequest(createRequestContext(request)); //獲取所有請求 for (Object obItem : items) { FileItem item = (FileItem) obItem; //獲取每個請求的文件 if (LOG.isDebugEnabled()) { LOG.debug("Found item" + item.getFieldName()); } if (item.isFormField()) { //普通表單提交 LOG.debug("Item is a normal form field"); List<String> values; if (params.get(item.getFieldName()) != null) { values = params.get(item.getFieldName()); } else { values = new ArrayList<String>(); } String charset = request.getCharacterEncoding(); if (charset != null) { values.add(item.getString(charset)); } else { values.add(item.getString()); } params.put(item.getFieldName(), values); } else { //文件上傳請求 LOG.debug("Item is a file upload"); if (item.getName() == null || item.getName().trim().length() <= 0) { LOG.debug("No file has been uploded for the filed:" + item.getFieldName()); continue; } List<FileItem> values; if (files.get(item.getFieldName()) != null) { values = files.get(item.getFieldName()); } else { values = new ArrayList<FileItem>(); } values.add(item); files.put(item.getFieldName(), values); } } } catch (FileUploadBase.SizeLimitExceededException e) { System.out.println("錯誤1：" + e); if (LOG.isWarnEnabled()) { LOG.warn("Request exceeded size limit!", e); } String errorMessage = buildErrorMessage(e, new Object[]{e.getPermittedSize(), e.getActualSize()}); if (!errors.contains(errorMessage)) { errors.add(errorMessage); } } catch (Exception e) { System.out.println("錯誤1：" + e); if (LOG.isWarnEnabled()) { LOG.warn("Unable to parse request", e); } String errorMessage = buildErrorMessage(e, new Object[]{}); if (!errors.contains(errorMessage)) { errors.add(errorMessage); } } } |
2. 文件上傳監(jiān)聽文件FileUploadProgressListener.java
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public class FileUploadProgressListener implements ProgressListener { private final HttpSession session; private final DecimalFormat format = new DecimalFormat("#00.0"); public FileUploadProgressListener(HttpServletRequest request) { session = request.getSession(); FileUploadStatus status = new FileUploadStatus(); session.setAttribute("uploadStatus", status); } @Override public void update(long pBytesRead, long pContentLength, int pItems) { FileUploadStatus uploadStatus = (FileUploadStatus) session.getAttribute("uploadStatus"); Double uploadRate = (double) (pBytesRead * 100 / pContentLength); uploadStatus.setUploadRate(Double.valueOf(format.format(uploadRate))); uploadStatus.setReadedBytes(pBytesRead / 1024); uploadStatus.setTotalBytes(pContentLength / 1024); uploadStatus.setCurrentItems(pItems); }} |
3. 添加狀態(tài)文件：FileUploadStatus.java
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public class FileUploadStatus { private Double uploadRate = 0.0; private Long readedBytes = 0L; private Long totalBytes = 0L; private int currentItems = 0; private Long uploadSpeed = 0L; private Long startTime = System.currentTimeMillis(); private Long readedTimes = 0L; private Long totalTimes = 0L; // "-1" 錯誤 "0" 正常 "1" 完成 private String error = "0"; ... setter getter方法 ... } |
4. Action類（如果是多文件上傳，則將File FileName ContentType定義成數(shù)組形式即可）
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/** * 利用io流上傳文件 */public class FileStreamUploadAction extends ActionSupport { /** * serialVersionUID作用： ---相當于類的身份證。 序列化時為了保持版本的兼容性，即在版本升級時反序列化仍保持對象的唯一性。 * 有兩種生成方式： 一個是默認的1L，比如：private static final long serialVersionUID = 1L; * 一個是根據(jù)類名、接口名、成員方法及屬性等來生成一個64位的哈希字段，比如： private static final long * serialVersionUID = xxxxL; */ private static final long serialVersionUID = 1L; private File image; private String imageFileName; private String imageContentType; private String message; public String uploadFile() { FileInputStream in = null; FileOutputStream out = null; System.out.println("文件名：" + imageFileName); try { this.setNewFileName(imageFileName); String realPath = ServletActionContext.getServletContext() .getRealPath("/file"); File filePath = new File(realPath); if (!filePath.exists()) { // 如果保存的路徑不存在則創(chuàng)建 filePath.mkdir(); } if (image == null) { message = "上傳文件為空"; System.out.println(message); } else { File saveFile = new File(filePath, this.getNewFileName()); out = new FileOutputStream(saveFile); } in = new FileInputStream(image); byte[] byt = new byte[1024]; int length = 0; while ((length = in.read(byt)) > 0) { out.write(byt, 0, length); out.flush(); } message = "上傳成功"; System.out.println(message); } catch (FileNotFoundException e) { message = "找不到文件！"; e.printStackTrace(); } catch (IOException e) { message = "文件讀取失敗！"; e.printStackTrace(); } finally { closeStream(in, out); } return "uploadSucc"; } public void closeStream(FileInputStream in, FileOutputStream out) { try { if (in != null) { in.close(); } if (out != null) { out.close(); } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } ... setter() getter() ... } |
獲取進度的Action
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public class FileProgressAction extends ActionSupport { private static final long serialVersionUID = 1L; private FileUploadStatus uploadStatus; public String uploadPercent() { HttpSession session = ServletActionContext.getRequest().getSession(); this.uploadStatus = (FileUploadStatus) session.getAttribute("uploadStatus"); if (uploadStatus == null) { System.out.println("action is null"); uploadStatus = new FileUploadStatus(); uploadStatus.setCurrentItems(0); } return "getPercent"; } public FileUploadStatus getUploadStatus() { return uploadStatus; } public void setUploadStatus(FileUploadStatus uploadStatus) { this.uploadStatus = uploadStatus; }} |
5.struts.xml中
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<struts> <constant name="struts.multipart.maxSize" value="2147483648"/><!-- 默認值為2M,設(shè)置為2G --> <constant name="struts.custom.i18n.resources" value="messageResource" /> <constant name="struts.i18n.encoding" value="utf-8" /> <constant name="struts.multipart.saveDir" value="e:/fileUpload"/><!-- 臨時路徑 --> <!-- 加載自定義的文件讀取配置文件 --> <bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="Refactor" class="com.nova.core.RefactorMultiPartRequest" scope="default" /> <constant name="struts.multipart.handler" value="Refactor" /> <!-- 這里配置struts.multipart.handler --> <package name="ajaxUpload" extends="json-default"> <!-- json-default需要struts2-json-plugin-2.3.3.jar --> <action name="ajaxUploadFile_*" class="com.nova.action.FileStreamUploadAction" method="{1}"> <result type="json" name="uploadSucc"> <param name="root">newFileName</param> <param name="contentType"> text/html </param> </result> </action> <action name="uploadPercent_*" class="com.nova.action.FileProgressAction" method="{1}"> <result name="getPercent" type="json"> <param name="root">uploadStatus</param> </result> </action> </package> </struts> |
二. 進度條顯示
View頁面設(shè)置，利用ajaxfileupload.js來獲取文件并進行異步上傳，bootstrap中的進度條效果顯示進度（利用setInterval間斷的獲取進度信息來形式一種進度的前進顯示）
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title><link rel="stylesheet" type="text/css" href="bootstrap/css/bootstrap.css" rel="external nofollow" ><link rel="stylesheet" type="text/css" href="bootstrap/css/bootstrap-responsive.css" rel="external nofollow" ><script type="text/javascript" src="js/jquery.js"></script><script type="text/javascript" src="js/ajaxfileupload.js"></script><script type="text/javascript" src="<%=request.getContextPath() %>/bootstrap/js/bootstrap.js"></script><script type="text/javascript" src="<%=request.getContextPath() %>/bootstrap/js/jquery.showLoading.min.js"></script><script type="text/javascript"> var setinterval; $(document).ready(function(){ $("#upload").click(function(){ $("#upload").addClass("disabled"); $("#upload").attr("disabled" ,true); $("#upload").attr("title" ,"文件上傳中..."); uploadFile(); setinterval = setInterval(uploadProgress,200); }); }); //文件上傳 function uploadFile(){ $.ajaxFileUpload({ url:'ajaxUploadFile_uploadFile.action', secureuri:false, //是否采用安全協(xié)議，默認為false fileElementId:'image', dataType: 'json', success: function (data){ $("#showImage").attr("src","/FileUpLoadTest/file/"+data); } }); } //上傳進度 function uploadProgress(){ $.get("uploadPercent_uploadPercent.action","",function(data){ $("#ProgressRate").html("上傳速度：" + data.uploadRate + "%"); $("#readBytes").html("以讀取：" + data.readedBytes + " KB"); $("#totalBytes").html("總大小：" + data.totalBytes + " KB"); $("#progress").attr("style","width:" + data.uploadRate + "%;"); $("#progress").html(data.uploadRate + "%"); if(data.uploadRate == 100){ clearInterval(setinterval); $("#progress").html("上傳成功"); $("#upload").removeClass("disabled"); $("#upload").attr("disabled" ,false); } }); }</script></head><body> <div class="navbar navbar-inverse navbar-fixed-top"> <div class="navbar-inner"> <div class="container"> <button type="button" class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse"> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button> <a class="brand" href="#" rel="external nofollow" >文件異步上傳+進度條</a> </div> </div> </div> <br><br><br> <div class="container"> <input type="file" name="image" id="image"/><br/> //file的name屬性必須設(shè)置的與后臺Action中file的名稱是相同的，否則ajaxFileUpload獲取不到文件信息 <input type="button" id="upload" value="上傳" class="btn btn-info" title=""/><br/> <img alt="" src="" id="showImage"> <div id="ProgressRate"></div> <div id="readBytes"></div> <div id="totalBytes"></div> <div id="uploadTimes"></div> <div class="progress progress-striped span4"> <div id="progress" class="bar"> </div> </div> </div></body></html> |
三、總結(jié)
用這種方法獲取上傳進度有一個缺點：讀取進度階段是文件從指定目錄開始在臨時文件中存儲的過程，而文件上傳則是重臨時路徑下將文件轉(zhuǎn)移到目標路徑下，這樣就造成了一個時間差，就是讀取進度總會比上傳文件快，上傳的文件越大這個缺點越是明顯。
以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持服務(wù)器之家。
