在java中向servlet发送图像如何在servlet中获取图像

Question

我正在将图像从 android 手机发送到服务器，这是一个 servlet，我为此使用 HttpClient 和 HttpPost，并在发送前使用 ByteArrayBody 存储图像。

如何从 Servlet 中的 post 请求中提取图像。

这是我发送帖子请求的代码

String postURL = //server url;

HttpClient httpClient = new DefaultHttpClient();
HttpPost postRequest = new HttpPost(postURL);

ByteArrayBody bab = new ByteArrayBody(imageBytes,"file_name_ignored");
MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
reqEntity.addPart("source", bab);
postRequest.setEntity(reqEntity);

HttpResponse response = httpClient.execute(postRequest);

Answer 1

使用commons fileupload 之类的东西。

在 Apache 文档以及整个网络中都有示例。

Answer 2

Servlet 3.0 支持读取多部分数据。 MutlipartConfig support in Servlet 3.0 如果使用 @MutlipartConfig 注释对 servelt 进行注释，则容器负责通过

使 Multipart 部分可用

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

Answer 3

使用http://commons.apache.org/fileupload/using.html

private DiskFileItemFactory fif = new DiskFileItemFactory(); 

protected void doPost(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException {
    boolean isMultipart = ServletFileUpload.isMultipartContent(req);

    if(!isMultipart)
        throw new ServletException("upload using multipart");

    ServletFileUpload upload = new ServletFileUpload(fif);
    upload.setSizeMax(1024 * 1024 * 10 /* 10 mb */);
    List<FileItem> items;
    try {
        items = upload.parseRequest(req);
    } catch (FileUploadException e) {
        throw new ServletException(e);
    }

    if(items == null || items.size() == 0)
        throw new ServletException("No items uploaded");

    FileItem item = items.get(0);
    // do something with file item...
}