一. struts2读取进度原理分析(作为草稿存了好久,刚刚发布出来......)
1. 在strut2中控制文件上传信息的类是实现MultiPartRequest接口的JakartaMultiPartRequest
其实第一次看到源文件时我打了个退堂鼓,因为觉得内容太长了,不想看。冷静下来将思路理顺,将分开的各个方法还原到一个方方中中,发现还是很好理解的:
@Override public void parse(HttpServletRequest request, String saveDir) throws IOException { setLocale(request);
//规定了File文件的格式(如文件名必须是xxFileName,文件类型xxContentType),并定义了File的保存路径 DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);//处理文件上传的servlet upload.setProgressListener(new FileUploadProgressListener(request)); //为文件上传添加监听 factory.setSizeThreshold(0); //if (saveDir != null factory.setRepository(new File(saveDir));//临时路径 } try { upload.setSizeMax(maxSize); List items = upload.parseRequest(createRequestContext(request)); //获取所有请求 for (Object obItem : items) { FileItem item = (FileItem) obItem; //获取每个请求的文件 if (LOG.isDebugEnabled()) { LOG.debug("Found item" + item.getFieldName()); } if (item.isFormField()) { //普通表单提交 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 { //文件上传请求 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("错误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("错误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. 文件上传监听文件FileUploadProgressListener.java
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. 添加状态文件:FileUploadStatus.java
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" 错误 "0" 正常 "1" 完成 private String error = "0"; ... setter getter方法 ... }
4. Action类(如果是多文件上传,则将File FileName ContentType定义成数组形式即可)
/** * 利用io流上传文件 */ public class FileStreamUploadAction extends ActionSupport { /** * serialVersionUID作用: ---相当于类的身份证。 序列化时为了保持版本的兼容性,即在版本升级时反序列化仍保持对象的唯一性。 * 有两种生成方式: 一个是默认的1L,比如:private static final long serialVersionUID = 1L; * 一个是根据类名、接口名、成员方法及属性等来生成一个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()) { // 如果保存的路径不存在则创建 filePath.mkdir(); } if (image == null) { message = "上传文件为空"; 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 = "上传成功"; System.out.println(message); } catch (FileNotFoundException e) { message = "找不到文件!"; e.printStackTrace(); } catch (IOException e) { message = "文件读取失败!"; 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() ... }
获取进度的Action
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
<struts> <constant name="struts.multipart.maxSize" value="2147483648"/><!-- 默认值为2M,设置为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"/><!-- 临时路径 --> <!-- 加载自定义的文件读取配置文件 --> <bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="Refactor" class="com.nova.core.RefactorMultiPartRequest" scope="default" /> <constant name="struts.multipart.handler" value="Refactor" /> <!-- 这里配置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. 进度条显示
View页面设置,利用ajaxfileupload.js来获取文件并进行异步上传,bootstrap中的进度条效果显示进度(利用setInterval间断的获取进度信息来形式一种进度的前进显示)
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <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"> <link rel="stylesheet" type="text/css" href="bootstrap/css/bootstrap-responsive.css"> <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" ,"文件上传中..."); uploadFile(); setinterval = setInterval(uploadProgress,200); }); }); //文件上传 function uploadFile(){ $.ajaxFileUpload({ url:'ajaxUploadFile_uploadFile.action', secureuri:false, //是否采用安全协议,默认为false fileElementId:'image', dataType: 'json', success: function (data){ $("#showImage").attr("src","/FileUpLoadTest/file/"+data); } }); } //上传进度 function uploadProgress(){ $.get("uploadPercent_uploadPercent.action","",function(data){ $("#ProgressRate").html("上传速度:" + data.uploadRate + "%"); $("#readBytes").html("以读取:" + data.readedBytes + " KB"); $("#totalBytes").html("总大小:" + data.totalBytes + " KB"); $("#progress").attr("style","" + data.uploadRate + "%;"); $("#progress").html(data.uploadRate + "%"); if(data.uploadRate == 100){ clearInterval(setinterval); $("#progress").html("上传成功"); $("#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="#">文件异步上传+进度条</a> </div> </div> </div> <br><br><br> <div class="container"> <input type="file" name="image" id="image"/><br/> //file的name属性必须设置的与后台Action中file的名称是相同的,否则ajaxFileUpload获取不到文件信息 <input type="button" id="upload" value="上传" 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、总结
用这种方法获取上传进度有一个缺点:读取进度阶段是文件从指定目录开始在临时文件中存储的过程,而文件上传则是重临时路径下将文件转移到目标路径下,这样就造成了一个时间差,就是读取进度总会比上传文件快,上传的文件越大这个缺点越是明显。