servlet中实现最基本的上传文件

在servlet当中，经常用到文件上传，目前倒是有不少上传的组件，但我觉得还是自己动手试一下自己写一个比较好。于是就写了下面这些代码。

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		DataInputStream in = null;
		FileOutputStream out = null;
		String contentType = null;
		contentType = request.getContentType();

		if (contentType != null
				&& contentType.indexOf("multipart/form-data") != -1) {
			String FileName = "C:\\myfile";
			File file = new File(FileName);
			out = new FileOutputStream(file);

			in = new DataInputStream(request.getInputStream());

			byte[] dataBytes = new byte[1024 * 2];
			int byteRead = 0;
			while ((byteRead = in.read(dataBytes)) != -1) {
				out.write(dataBytes, 0, byteRead);
			}
			out.flush();
			out.close();
		}
	}

<form id="form1" enctype="multipart/form-data" name="form1" method="post" action="servlet/FindSina">
  <label>File
  <input type="file" name="textfield"/>
  </label>
  <p>
    <label>
    <input type="submit" name="Submit" value="submit" />
    </label>
  </p>
</form>