jsp使用servlet實現文件上傳
阿新 • • 發佈：2017-09-14
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1.在index.jsp中寫入以下代碼
<form method="post" action="demo3" enctype="multipart/form-data"> 選擇一個文件: <input type="file" name="uploadFile"/> <br/><br/> <input type="submit" value="上傳"/> </form>
2.在src中創建ServletDemo3類
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;//此三個包為 正常包以外 額外需要下載導入
public class ServletDemo3 extends HttpServlet { private static final long serialVersionUID = 1L; // 上傳文件存儲目錄 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 /** * 上傳數據及保存文件 */ 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; } // 配置上傳參數 DiskFileItemFactory factory = new DiskFileItemFactory(); // 設置內存臨界值 - 超過後將產生臨時文件並存儲於臨時目錄中 factory.setSizeThreshold(MEMORY_THRESHOLD); // 設置臨時存儲目錄 factory.setRepository(new File(System.getProperty("java.io.tmpdir"))); ServletFileUpload upload = new ServletFileUpload(factory); // 設置最大文件上傳值 upload.setFileSizeMax(MAX_FILE_SIZE); // 設置最大請求值 (包含文件和表單數據) upload.setSizeMax(MAX_REQUEST_SIZE); // 中文處理 upload.setHeaderEncoding("UTF-8"); // 構造臨時路徑來存儲上傳的文件 // 這個路徑相對當前應用的目錄 String uploadPath = request.getServletContext().getRealPath("./") + File.separator + UPLOAD_DIRECTORY; // 如果目錄不存在則創建 File uploadDir = new File(uploadPath); if (!uploadDir.exists()) { uploadDir.mkdir(); } try { // 解析請求的內容提取文件數據 @SuppressWarnings("unchecked") List<FileItem> formItems = upload.parseRequest(request); if (formItems != null && formItems.size() > 0) { // 叠代表單數據 for (FileItem item : formItems) { // 處理不在表單中的字段 if (!item.isFormField()) { String fileName = new File(item.getName()).getName(); String filePath = uploadPath + File.separator + fileName; File storeFile = new File(filePath); // 在控制臺輸出文件的上傳路徑 System.out.println(filePath); // 保存文件到硬盤 item.write(storeFile); request.setAttribute("message", "文件上傳成功!"); } } } } catch (Exception ex) { request.setAttribute("message", "錯誤信息: " + ex.getMessage()); } // 跳轉到 message.jsp request.getServletContext().getRequestDispatcher("/message.jsp").forward( request, response); } }
3.在WEB-INF進行配置文件
<servlet>
<servlet-name>servletDemo3</servlet-name>
<servlet-class>com.neunb.servlet.ServletDemo3</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>servletDemo3</servlet-name>
<url-pattern>/demo3</url-pattern>
</servlet-mapping>
4.創建message.jsp 顯示上傳結果
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>文件上傳結果</title>
</head>
<body>
<h2>${message}</h2>
</body>
</html>
5.上傳文件運行結果
jsp使用servlet實現文件上傳