如何检索上传的图像并使用JSP保存到文件？

Question

抱歉,我对jsp完全不熟悉.

如何检索上传的图像并使用jsp保存到文件？

Answer 1

1. 创建一个Web项目.

2. 创建至少包含以下内容的JSP文件:

   <form action="upload" method="post" enctype="multipart/form-data">
       <input type="file" name="file">
       <input type="submit">
   </form>
   

3. 转到Apache Commons FileUpload主页,阅读 " 用户指南"和" 常见问题解答"部分.

4. 下载以下库的二进制文件:

   • 公地文件上传
   • 公地IO

5. 解压缩拉链并将JAR文件放在/WEB-INF/libWeb项目中.

6. 创建一个至少包含以下内容的Servlet类:

   public class UploadServlet extends HttpServlet {
       @Override
       protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
           List<FileItem> items = null;
           try {
               items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);
           } catch (FileUploadException e) {
               throw new ServletException("Cannot parse multipart request.", e);
           }
           for (FileItem item : items) {
               if (item.isFormField()) {
                   // Process regular form fields here the same way as request.getParameter().
                   // You can get parameter name by item.getFieldName();
                   // You can get parameter value by item.getString();
               } else {
                   // Process uploaded fields here.
                   String filename = FilenameUtils.getName(item.getName()); // Get filename.
                   File file = new File("/path/to/uploads", filename); // Define destination file.
                   item.write(file); // Write to destination file.
               }
           }
           // Show result page.
           request.getRequestDispatcher("result.jsp").forward(request, response);
       }
   }
   

7. 在web.xml中映射servlet,如下所示:

   <servlet>
       <servlet-name>upload</servlet-name>
       <servlet-class>mypackage.UploadServlet</servlet-class>
   </servlet>
   <servlet-mapping>
       <servlet-name>upload</servlet-name>
       <url-pattern>/upload</url-pattern>
   </servlet-mapping>
   

那应该是它.当您在JSP中提交表单时,它将调用/upload与<url-pattern>servlet 匹配的操作,然后servlet将在该doPost()方法中执行其任务.最后,这一切都相当简单.希望这可以帮助.