ajax上传带进度条案例

package com.bjinfotech.practice.ajax; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.log4j.Logger; /** * 上传文件命令服务 */ public class FileUploadCommandService extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet { private static final long serialVersionUID = -3946579508549209629L; //Join命令字 public static final String PROTOCOL_COMMAND_JOIN_KEY="join"; //轮询命令字 public static final String PROTOCOL_COMMAND_POLL_KEY="uploadStatus"; //取消上传命令字 public static final String PROTOCOL_COMMAND_CANCELUPLOAD_KEY="cancelUpload"; //下载文件命令字 public static final String PROTOCOL_COMMAND_DOWNFILE_KEY="downFile"; //文件id public static final String PROTOCOL_COMMAND_FILEID_KEY="fileId"; //删除文件命令字 public static final String PROTOCOL_COMMAND_DELFILE_KEY="deleteFile"; Logger logger=Logger.getLogger(FileUploadCommandService.class); public FileUploadCommandService() { super(); } public void init(){ UploadSessionManager.getInstance().start(); } public void destroy(){ UploadSessionManager.getInstance().stop(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request,response); } /** * 设置Ajax回应的header * @param response */ private void setAjaxResponseHeader(HttpServletResponse response){ response.setContentType("text/xml"); response.setCharacterEncoding("UTF-8"); response.setHeader("Cache-Control", "no-cache"); } /** * 设置文件下载的header * @param response * @param fileName * @throws UnsupportedEncodingException */ private void setFileDownloadResponseHeader(HttpServletResponse response,String fileName) throws UnsupportedEncodingException{ response.setHeader("Cache-Control", "no-cache"); response.setContentType("application/octet-stream; CHARSET=utf8"); response.setHeader("Content-Disposition","attachment; filename="+ java.net.URLEncoder.encode(fileName,"UTF-8")); } /** * 发送序列化的Bean * @param response * @param beanObj * @throws IOException */ private void sendSerializedBean(HttpServletResponse response,Object beanObj) throws IOException{ setAjaxResponseHeader(response); response.getWriter().write(XmlUnSerializer.serializeBean(beanObj)); } /** * 回应join请求，将生成的uploadSession id、forwardURL保存到session中，并将其作为response内容发送 * @param request * @param response * @throws ServletException * @throws IOException */ private void responseJoinRequest(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{ logger.debug("发送Join回应"); UploadSessionImpl uSession=new UploadSessionImpl(UploadSessionManager.getInstance().createSessionId()); uSession.setFUploadStatusBean(FileUploadStatusBeanManager.initFileUploadStatusBean()); FileUploadStatusBeanManager.setFileUploadStatusBeanIntoUploadSession(uSession); InteractionMessage im=new InteractionMessage(); im.setMsg(uSession.getId()); request.getSession().setAttribute(Constant.SESSION_KEY,uSession.getId()); request.getSession().setAttribute(Constant.FORWARDURL_KEY,Utils.getForwardURLFromHttpRequest(request)); logger.debug("将会话Id["+uSession.getId()+"]保存在session["+request.getSession().getId()+"]中"); sendSerializedBean(response,im); } /** * 回应上传状态查询 * @param request * @param response * @throws IOException */ private void responseFileUploadStatusPoll(HttpServletRequest request,HttpServletResponse response) throws IOException{ logger.debug("发送上传状态回应"); sendSerializedBean( response, FileUploadStatusBeanManager.getFileUploadStatusBeanFromUploadSession(Utils.getSessionIdFromHttpRequest(request)).getFUploadStatusBean() ); } /** * 处理取消文件上传,注意这并不能终止form的提交过程 * @param request * @param response * @throws IOException */ private void processCancelFileUpload(HttpServletRequest request,HttpServletResponse response) throws IOException{ UploadSessionImpl uSession=FileUploadStatusBeanManager.getFileUploadStatusBeanFromUploadSession(Utils.getSessionIdFromHttpRequest(request)); uSession.getFUploadStatusBean().setCancel(true); FileUploadStatusBeanManager.setFileUploadStatusBeanIntoUploadSession(uSession); responseFileUploadStatusPoll(request,response); } /** * 在上传文件列表中查找与文件id相关的文件名 * @param request * @param fileId 文件id * @return　找到返回文件名,否则返回null */ private String findFileNameInFileUploadedList(HttpServletRequest request,int fileId){ UploadSessionImpl uSession=FileUploadStatusBeanManager.getFileUploadStatusBeanFromUploadSession(Utils.getSessionIdFromHttpRequest(request)); if (uSession.getFUploadStatusBean().getUploadFileUrlList().size()>fileId){ return (String)uSession.getFUploadStatusBean().getUploadFileUrlList().get(fileId); } else{ return null; } } /** * 下载文件 * @param request 其中downFile参数值为下载文件名 * @param response * @throws IOException */ private void downloadFile(HttpServletRequest request,HttpServletResponse response) throws IOException{ int fileId=Integer.parseInt(request.getParameter(PROTOCOL_COMMAND_FILEID_KEY)); String fileName=findFileNameInFileUploadedList(request,fileId); if (fileName!=null){ setFileDownloadResponseHeader(response,fileName); File uploadedFile = new File(request.getSession().getServletContext().getRealPath(Constant.UPLOAD_DIR)+File.separator+fileName); DataInputStream is=new DataInputStream(new FileInputStream(uploadedFile)); DataOutputStream os=new DataOutputStream(response.getOutputStream()); byte[] readBytes=new byte[128]; while(is.read(readBytes)!=-1){ os.write(readBytes); } os.close(); is.close(); } else{ InteractionMessage im=new InteractionMessage(); im.setMsg("下载文件失败：没有找到文件"); sendSerializedBean( response,im); } } /** * 删除文件 * @param request 其中deletedFile参数值为删除文件名 * @param response * @throws IOException * @throws ServletException * @throws IOException */ private void deleteFile(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{ logger.debug("发送删除文件回应"); InteractionMessage im=new InteractionMessage(); int fileId=Integer.parseInt(request.getParameter(PROTOCOL_COMMAND_FILEID_KEY)); String fileName=findFileNameInFileUploadedList(request,fileId); if (fileName!=null){ File deletedFile = new File(request.getSession().getServletContext().getRealPath(Constant.UPLOAD_DIR)+File.separator+fileName); if (deletedFile.delete()){ UploadSessionImpl uSession=FileUploadStatusBeanManager.getFileUploadStatusBeanFromUploadSession(Utils.getSessionIdFromHttpRequest(request)); uSession.getFUploadStatusBean().getUploadFileUrlList().remove(fileId); FileUploadStatusBeanManager.setFileUploadStatusBeanIntoUploadSession(uSession); im.setMsg("删除文件["+fileName+"]成功!"); } else{ im.setMsg("删除文件["+fileName+"]失败!"); } } else{ im.setMsg("删除文件失败：没有找到文件"); } sendSerializedBean( response,im); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); logger.debug("session id="+request.getSession().getId()); //首先处理join if (request.getParameter(PROTOCOL_COMMAND_JOIN_KEY)!=null){ logger.debug("收