ajax servlet上傳檔案
阿新 • • 發佈：2019-02-05
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Java程式碼
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package com.wang; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.util.List; 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.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; /** * Servlet implementation class UploadServlet */ @WebServlet("/UploadServlet") public class UploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; // 上傳檔案儲存目錄 private static final String UPLOAD_DIRECTORY = "upload"; // 上傳配置 private static final int MEMORY_THRESHOLD = 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 /** * 上傳資料及儲存檔案 */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 檢測是否為多媒體上傳 if (!ServletFileUpload.isMultipartContent(request)) { // 如果不是則停止 PrintWriter writer = response.getWriter(); writer.println("Error: 表單必須包含 enctype=multipart/form-data"); writer.flush(); return; } // 配置上傳引數 DiskFileItemFactory factory = new DiskFileItemFactory(); // 設定記憶體臨界值 - 超過後將產生臨時檔案並存儲於臨時目錄中 factory.setSizeThreshold(MEMORY_THRESHOLD); // 設定臨時儲存目錄 factory.setRepository(new File(System.getProperty("java.io.tmpdir"))); ServletFileUpload upload = new ServletFileUpload(factory); // 設定最大檔案上傳值 upload.setFileSizeMax(MAX_FILE_SIZE); // 設定最大請求值 (包含檔案和表單資料) upload.setSizeMax(MAX_REQUEST_SIZE); // 構造臨時路徑來儲存上傳的檔案 // 這個路徑相對當前應用的目錄 String uploadPath = getServletContext().getRealPath("./") + File.separator + UPLOAD_DIRECTORY; // 如果目錄不存在則建立 File uploadDir = new File(uploadPath); if (!uploadDir.exists()) { uploadDir.mkdir(); } try { // 解析請求的內容提取檔案資料 @SuppressWarnings("unchecked") List<FileItem> formItems = upload.parseRequest(request); if (formItems != null && formItems.size() > 0) { // 迭代表單資料 for (FileItem item : formItems) { // 處理不在表單中的欄位 if (!item.isFormField()) { String fileName = new File(item.getName()).getName(); String filePath = uploadPath + File.separator + fileName; File storeFile = new File(filePath); // 在控制檯輸出檔案的上傳路徑 System.out.println(filePath); // 儲存檔案到硬碟 item.write(storeFile); request.setAttribute("message", "檔案上傳成功!"); } } } } catch (Exception ex) { request.setAttribute("message", "錯誤資訊: " + ex.getMessage()); } // 跳轉到 message.jsp PrintWriter out = response.getWriter(); out.print("success"); out.flush(); out.close(); } }
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html程式碼
<!DOCTYPE html> <html> <head> <title>upload.html</title> <meta name="keywords" content="keyword1,keyword2,keyword3"> <meta name="description" content="this is my page"> <meta name="content-type" content="text/html; charset=UTF-8"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body> <form id="uploadForm" enctype="multipart/form-data"> <input id="file" type="file" name="file" /> <button id="upload" type="button">upload</button> </form> </body> <script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script> <script type="text/javascript"> $("#upload").click(function() { $.ajax({ url:'http://127.0.0.1:8080/u/UploadServlet', type:'POST', cache:false, data:new FormData($('#uploadForm')[0]), processData : false, contentType : false }).done(function(res) { alert(res); }).fail(function(res) { alert(res); }); }); </script> </html>
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一：commons-upload在解析request的inputstream會首先獲取boundary，這裡面記錄著檔案流的起始和結束位置。