从POST请求中检索图像

Question

我正在尝试将图片发送到我的java servlet（托管在amazon ec2上）以便稍后将其传输到amazon s3，并想知道如何从post请求中检索图像。

上传代码

请求通过iOS RestKit API发送（pic.imageData是NSData类型）：

RKParams* params = [RKParams params];

[params setValue:pic.dateTaken forParam:@"dateTaken"];
[params setValue:pic.dateUploaded forParam:@"dateUploaded"];

[params setData:pic.imageData MIMEType:@"image/jpeg" forParam:@"image"];

[RKClient sharedClient].username = deviceID;
[RKClient sharedClient].password = sessionKey;

[RKClient sharedClient].authenticationType = RKRequestAuthenticationTypeHTTPBasic;

uploadPictureRequest = [[RKClient sharedClient] post:kUploadPictureServlet params:params delegate:self];

解析代码存根

这就是我解析Java servlet上其他2个参数的方法：

double dateTaken = Double.parseDouble(req.getParameter("dateTaken"));
double dateUploaded = Double.parseDouble(req.getParameter("dateUploaded"));

问题

问题是：如何在服务器上检索和解析图像？

Answer 1

Servlet 3.0支持阅读多部分数据。 Servlet 3.0中的MutlipartConfig支持如果使用@MutlipartConfig注释对servelt进行注释，则容器负责通过

使Multipart部件可用

HttpServletRequest.getParts()
HttpServletRequest.getPart("name");

<强>参考文献：

• Servlet 3.0 File Upload handing files and params
• Servlet 3.0 File upload Example

Answer 2

根据这一点，使用Apache Commons FileUpload：

 // or @SuppressWarnings("unchecked")
 @SuppressWarnings("rawtypes")
 public void doPost(HttpServletRequest request, HttpServletResponse response) 
         throws ServletException, IOException {
     if (ServletFileUpload.isMultipartContent(request)) {
         final FileItemFactory   factory = new DiskFileItemFactory();
         final ServletFileUpload upload  = new ServletFileUpload(factory);

         try {
             final List items = upload.parseRequest(request);

             for (Iterator itr = items.iterator(); itr.hasNext();) {
                 final FileItem item = (FileItem) itr.next();

                 if (!item.isFormField()) {
                    /*
                     * TODO: (for you)
                     *  1. Verify that file item is an image type.
                     *  2. And do whatever you want with it.
                     */
                 }
             }
         } catch (FileUploadException e) {
             e.printStackTrace();
         }
     }
 }

请参阅FileItem API参考文档以确定下一步操作。