AJAX和JSP实现的基于WEB的文件上传的进度控制代码第2/2页

 更新时间:2007年05月19日 00:00:00   作者:  

  2.1.3. 后台服务类(BackGroundService)

   BackGroundService这个Servlet类负责接收Form Post数据、回应状态轮询请求、处理取消文件上传的请求。 尽管可以把这些功能相互分离开来,但为了简单明了,还是将它们放到Servlet中,只是由不同的方法进行分割。 源代码如下:

/**
 * 本例程演示了通过Web上传文件过程中的进度显示。您可以对本例程进行任何修改和使用。
 * 如果需要转载本例程,请您注明作者。
 *
 * 作者: 刘作晨
 * EMail:liuzuochen@gmail.com
 */
package liuzuochen.sample.upload;

/** * Title: 后台服务 * * Description: 为客户端提供上传及文件传输状态查询服务 * */ import java.io.File; import java.io.IOException; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.*; public class BackGroundService extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet { public static final String UPLOAD_DIR = "/upload"; public static final String DEFAULT_UPLOAD_FAILURE_URL = "./result.jsp"; public BackGroundService() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } /** * 从文件路径中取出文件名 */ private String takeOutFileName(String filePath) { int pos = filePath.lastIndexOf(File.separator); if (pos > 0) { return filePath.substring(pos + 1); } else { return filePath; } } /** * 从request中取出FileUploadStatus Bean */ public static FileUploadStatus getStatusBean( HttpServletRequest request) { BeanControler beanCtrl = BeanControler.getInstance(); return beanCtrl.getUploadStatus(request.getRemoteAddr()); } /** * 把FileUploadStatus Bean保存到类控制器BeanControler */ public static void saveStatusBean( HttpServletRequest request, FileUploadStatus statusBean) { statusBean.setUploadAddr(request.getRemoteAddr()); BeanControler beanCtrl = BeanControler.getInstance(); beanCtrl.setUploadStatus(statusBean); } /** * 删除已经上传的文件 */ private void deleteUploadedFile(HttpServletRequest request) { FileUploadStatus satusBean = getStatusBean(request); for (int i = 0; i < satusBean.getUploadFileUrlList().size(); i++) { File uploadedFile = new File(request.getRealPath(UPLOAD_DIR) + File.separator + satusBean.getUploadFileUrlList(). get(i)); uploadedFile.delete(); } satusBean.getUploadFileUrlList().clear(); satusBean.setStatus("删除已上传的文件"); saveStatusBean(request, satusBean); } /** * 上传过程中出错处理 */ private void uploadExceptionHandle( HttpServletRequest request, String errMsg) throws ServletException, IOException { //首先删除已经上传的文件 deleteUploadedFile(request); FileUploadStatus satusBean = getStatusBean(request); satusBean.setStatus(errMsg); saveStatusBean(request, satusBean); } /** * 初始化文件上传状态Bean */ private FileUploadStatus initStatusBean(HttpServletRequest request) { FileUploadStatus satusBean = new FileUploadStatus(); satusBean.setStatus("正在准备处理"); satusBean.setUploadTotalSize(request.getContentLength()); satusBean.setProcessStartTime(System.currentTimeMillis()); satusBean.setBaseDir(request.getContextPath() + UPLOAD_DIR); return satusBean; } /** * 处理文件上传 */ private void processFileUpload(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { DiskFileItemFactory factory = new DiskFileItemFactory(); //设置内存缓冲区,超过后写入临时文件 factory.setSizeThreshold(10240000); //设置临时文件存储位置 factory.setRepository(new File(request.getRealPath("/upload/temp"))); ServletFileUpload upload = new ServletFileUpload(factory); //设置单个文件的最大上传值 upload.setFileSizeMax(102400000); //设置整个request的最大值 upload.setSizeMax(102400000); upload.setProgressListener(new FileUploadListener(request)); //保存初始化后的FileUploadStatus Bean saveStatusBean(request, initStatusBean(request)); String forwardURL = ""; try { List items = upload.parseRequest(request); //获得返回url for (int i = 0; i < items.size(); i++) { FileItem item = (FileItem) items.get(i); if (item.isFormField()) { forwardURL = item.getString(); break; } } //处理文件上传 for (int i = 0; i < items.size(); i++) { FileItem item = (FileItem) items.get(i); //取消上传 if (getStatusBean(request).getCancel()) { deleteUploadedFile(request); break; } //保存文件 else if (!item.isFormField() && item.getName().length() > 0) { String fileName = takeOutFileName(item.getName()); File uploadedFile = new File(request.getRealPath(UPLOAD_DIR) + File.separator + fileName); item.write(uploadedFile); //更新上传文件列表 FileUploadStatus satusBean = getStatusBean(request); satusBean.getUploadFileUrlList().add(fileName); saveStatusBean(request, satusBean); Thread.sleep(500); } } } catch (FileUploadException e) { uploadExceptionHandle(request, "上传文件时发生错误:" + e.getMessage()); } catch (Exception e) { uploadExceptionHandle(request, "保存上传文件时发生错误:" + e.getMessage()); } if (forwardURL.length() == 0) { forwardURL = DEFAULT_UPLOAD_FAILURE_URL; } request.getRequestDispatcher(forwardURL).forward(request, response); } /** * 回应上传状态查询 */ private void responseStatusQuery(HttpServletRequest request, HttpServletResponse response) throws IOException { response.setContentType("text/xml"); response.setHeader("Cache-Control", "no-cache"); FileUploadStatus satusBean = getStatusBean(request); response.getWriter().write(satusBean.toJSon()); } /** * 处理取消文件上传 */ private void processCancelFileUpload(HttpServletRequest request, HttpServletResponse response) throws IOException { FileUploadStatus satusBean = getStatusBean(request); satusBean.setCancel(true); saveStatusBean(request, satusBean); responseStatusQuery(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { boolean isMultipart = ServletFileUpload.isMultipartContent(request); if (isMultipart) { processFileUpload(request, response); } else { request.setCharacterEncoding("UTF-8"); if (request.getParameter("uploadStatus") != null) { responseStatusQuery(request, response); } if (request.getParameter("cancelUpload") != null) { processCancelFileUpload(request, response); } } } }

  2.1.4. 文件上传状态控制类(BeanControler)

   这是一个单例类,它的功能是为客户端保存文件上传状态,这里我没有使用Session来存储文件上传状态,因为对于AJAX这种异步调用,服务器会开启不同的Session,所以无法通过Session保存文件上传状态。 我并不认为这种方法最好,如果有更好的方法,欢迎大家一起讨论。 源代码如下:

/**
 * 本例程演示了通过Web上传文件过程中的进度显示。您可以对本例程进行任何修改和使用。
 * 如果需要转载本例程,请您注明作者。
 *
 * 作者: 刘作晨
 * EMail:liuzuochen@gmail.com
 */
package liuzuochen.sample.upload; /** * Title: 类控制器 * * Description: 主要作用是对FileUploadStatus进行管理,为客户端提供相应的 * FileUploadStatus类对象。这是一个单例类。 * */ import java.util.Vector; public class BeanControler { private static BeanControler beanControler = new BeanControler(); private Vector vector = new Vector(); private BeanControler() { } public static BeanControler getInstance() { return beanControler; } /** * 取得相应FileUploadStatus类对象的存储位置 */ private int indexOf(String strID) { int nReturn = -1; for (int i = 0; i < vector.size(); i++) { FileUploadStatus status = (FileUploadStatus) vector.elementAt(i); if (status.getUploadAddr().equals(strID)) { nReturn = i; break; } } return nReturn; } /** * 取得相应FileUploadStatus类对象 */ public FileUploadStatus getUploadStatus(String strID) { return (FileUploadStatus) vector.elementAt(indexOf(strID)); } /** * 存储FileUploadStatus类对象 */ public void setUploadStatus(FileUploadStatus status) { int nIndex = indexOf(status.getUploadAddr()); if ( -1 == nIndex) { vector.add(status); } else { vector.insertElementAt(status, nIndex); vector.removeElementAt(nIndex + 1); } } /** * 删除FileUploadStatus类对象 */ public void removeUploadStatus(String strID){ int nIndex = indexOf(strID); if(-1!=nIndex) vector.removeElementAt(nIndex); } }

 2.2. 客户端代码

   客户端我们采用Prototype框架。请下载。

  2.2.1. AjaxWrapper.js

   AjaxWrapper.js对Prototype进行了封装。请下载分析

  2.2.2. fileUpload.html

   fileUpload.html是文件上传界面。 请下载。

  2.2.3. result.jsp

   result.jsp是文件上传结果显示界面。 请下载

  2.2.4. fileUpload.css

   fileUpload.css是样式文件。 源代码如下:

body {
  color:#000;
  background-color:white;
  font:15px Georgia, "Lucida Grande", Arial, sans-serif;
  letter-spacing:0.01em;
  margin:15px;
}
#controlPanel,#resultPanel{
  width:700px;
  margin:20px auto;
  padding:25px;
  border:3px solid gray;
  -moz-border-radius:10px;
  background:#f8f8f8;
}
#errorArea{
   width:400px;
  margin:20px auto;
  padding:25px;
  border:3px solid gray;
  -moz-border-radius:10px;
  background:red;
}
#normalMessageArea{
  width:400px;
  margin:20px auto;
  padding:25px;
  border:3px solid gray;
  -moz-border-radius:10px;
  background:yellow;
}
#progressBar { padding-top: 5px; }
  #totalProgressBarBox {
   width: 350px;
   height: 20px;
   border: 1px inset;
   background: #eee;
}
#totalProgressBarBoxContent {
  width: 0;
  height: 20px;
  border-right: 1px solid #444;
  background: #9ACB34;
}

 2.3. 配置文件

   web.xml中完成Servlet的配置。

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>AjaxPractice</display-name>
<servlet>
  <description></description>
  <display-name>BackGroundService</display-name>
  <servlet-name>BackGroundService</servlet-name>
  <servlet-class>liuzuochen.sample.upload.BackGroundService</servlet-class>
</servlet>

<servlet-mapping>
  <servlet-name>BackGroundService</servlet-name>
  <url-pattern>*.action</url-pattern>
</servlet-mapping>
<welcome-file-list>
  <welcome-file>index.html</welcome-file>
   <welcome-file>index.htm</welcome-file>
  <welcome-file>index.jsp</welcome-file>
  <welcome-file>default.html</welcome-file>
  <welcome-file>default.htm</welcome-file>
  <welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>

 3. 结语

   整个程序到这里就介绍完了,希望它多少能为您的工作或学习带来点儿帮助。

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