将Excel上传到Java Servlet，并在数据上传时获得结果

我有一个应用程序，我试图从浏览器上传一个Excel文件（约21,000行） – 应用程序是用JSP，Servlet，Apache POI和JDBC编写的。 现在使用Servlet从浏览器（jsp文件）上传文件，然后使用Apache POI读取excel文件的logging，然后将行写入到MySQL数据库。 上传成功运行并能够将logging插入到Mysql数据库中。 然而，jsp页面只停留在那里，只有几分钟后才会通知用户成功上传。

任何人都可以帮助我如何向用户显示浏览器上的消息，该文件已成功上传，但正在处理？ 任何更好的代码执行也请让我知道。 我的Servlet代码如下

import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Iterator; import java.util.List; import java.util.logging.Logger; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; 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.ServletFileUpload; import org.apache.commons.io.FilenameUtils; import org.json.simple.JSONObject; import src.com.pion.web.config.business.UploadFileProcessor; /** * Servlet implementation class UploadServlet */ @WebServlet(name = "UploadServlet", description = "Manages the uploaded servlet file and sends it to processing", urlPatterns = { "/upload.do" } ) public class UploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; private static final Logger LOGGER = Logger.getLogger(UploadServlet.class.getName()); private static final String UPLOAD_DIRECTORY = "upload"; private static final int THRESHOLD_SIZE = 1024 * 1024 * 3; // 3MB private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB public UploadServlet() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { throw new ServletException("GET method used with " + getClass( ).getName( )+": POST method required."); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //PrintWriter to send the JSON response back // checks if the request actually contains upload file if (!ServletFileUpload.isMultipartContent(request)) { PrintWriter writer = response.getWriter(); writer.println("Request does not contain upload data"); writer.flush(); return; } PrintWriter out = response.getWriter(); //set content type and header attributes response.setContentType("text/html"); response.setHeader("Cache-control", "no-cache, no-store"); response.setHeader("Pragma", "no-cache"); response.setHeader("Expires", "-1"); // configures upload settings DiskFileItemFactory factory = new DiskFileItemFactory(); factory.setSizeThreshold(THRESHOLD_SIZE); factory.setRepository(new File(System.getProperty("java.io.tmpdir"))); ServletFileUpload upload = new ServletFileUpload(factory); upload.setFileSizeMax(MAX_FILE_SIZE); upload.setSizeMax(MAX_REQUEST_SIZE); // constructs the directory path to store upload file String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY; // creates the directory if it does not exist File uploadDir = new File(uploadPath); if (!uploadDir.exists()) { uploadDir.mkdir(); } JSONObject myObj = new JSONObject(); String fileName = null; String fullName = null; File file = null; try { // parses the request's content to extract file data List formItems = upload.parseRequest(request); Iterator iter = formItems.iterator(); // iterates over form's fields while (iter.hasNext()) { FileItem item = (FileItem) iter.next(); // processes only fields that are not form fields if (!item.isFormField()) { fileName = new File(item.getName()).getName(); String filePath = uploadPath + File.separator + fileName; file = new File(filePath); fullName = item.getName().trim(); // saves the file on disk item.write(file); } } String message = null; UploadFileProcessor uploadProcessor = new UploadFileProcessor(); String extension = FilenameUtils.getExtension(fullName); if(extenter code hereension.trim().equalsIgnoreCase("xlsx")){ // Send the code for processing and later insert into database message = uploadProces`enter code `enter code here`here`sor.processExcelFile(file); } myObj.put("success", true); myObj.put("message", message + " item(s) were processed for file " + fileName); LOGGER.info(myObj.toString()); } catch(FileUploadException ex) { log("Error encountered while parsing the request",ex); myObj.put("success", false); LOGGER.info(myObj.toString()); } catch(Exception ex) { log("Error encountered while uploading file",ex); myObj.put("success", false); LOGGER.info(myObj.toString()); } out.close(); } } 

Answer 1

你可以做的是，把你的操作分成两种方法。

1. 上传文件
2. 读取文件并插入数据库

并从客户端，使用Ajax调用您的servlet的file upload方法。 并作为结果打印响应代码（成功= 200 /错误= 401等）作为输出到您的打印stream。

如果成功（responseCode = 200），在ajax成功块中，显示提示信息“上传成功，请等待……处理数据”，否则显示“错误”。 如果成功，则调用另一个JavaScript函数，类似上面的ajax到您的servlet的数据插入方法。

然后在那里设置响应代码，并根据您在servlet中设置的响应代码显示警报消息。

我会给一个样本片段。 （没有编译或testing，只是想引导你）你的客户端代码应该是这样的：

 function uploadFile(){ $.ajax({ url:"YourServlet", type: "POST", crossDomain: true, dataType:"json", data:"type=upload&other_related_data_you_require_to_process", success: function(data) { if(data.responseCode === 200){ alert("file is successfully updated!! Please wait till processing the data..."); processData(); } }, error: function(data){ alert("error in file Upload") } }); } function processData(){ $.ajax({ url:"YourServlet", type: "POST", crossDomain: true, dataType:"json", data:"type=processData&other_related_data_you_require_to_process", success: function(data) { if(data.responseCode === 200){ alert("data successfully processed!! records are inserted !!"); processData(); } }, error: function(data){ alert("error in file Upload") } }); } And your servlet code should look like: doPost(req, res){ String type = request.getParameter("type"); // your "other_related_data_you_require_to_process" comes here... int reponseCode = 404; boolean uploadSuccess = false; boolean dbInsertSucess = false; if("upload").equals(type){ // your code to upload the file: //if upload process is success: uploadSuccess = true; ... if(uploadSuccess){ reponseCode = 200; } }else if("processData").equals(type){ // your code to call database inserting process: //if insert process is success: dbInsertSucess = true; ... if(dbInsertSucess){ reponseCode = 200; } }else{ // any other type goes here. } // writing the output responseCode to json / printStream: PrintWriter out = null; try{ out = res.getWriter(); out.println("{responseCode: "+ responseCode + "}"); out.flush(); out.close(); }catch(Exception e){ e.printStackTrace(); } } 

一篇好文章可以在这里find