代码:

@WebServlet("/UploadServlet")

@MultipartConfig//表示文件上传注解

public class UploadServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		// 接收普通数据:

		request.setCharacterEncoding("UTF-8");

		String filedesc = request.getParameter("filedesc");

		System.out.println("文件描述"+filedesc);

		// 接收文件:

		Part part = request.getPart("upload");

		long size = part.getSize();// 获得文件大小:

		System.out.println("文件大小:"+size);

		String name = part.getName();

		System.out.println("文件表单中的name属性的名称"+name);

		// 获得文件名:

		String header = part.getHeader("Content-Disposition");

		int idx = header.lastIndexOf("filename=\"");

		String fileName = header.substring(idx+10, header.length()-1);

		System.out.println("文件名:"+fileName);

		// 获得文件内容:

		InputStream is = part.getInputStream();

		// 获得upload的路径:

		String path = this.getServletContext().getRealPath("/upload");

		OutputStream os = new FileOutputStream(path+"/"+fileName);

		byte[] b = new byte[1024];

		int len = 0;

		while((len = is.read(b))!=-1){

			os.write(b, 0, len);

		}

		is.close();

		os.close();

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doGet(request, response);

	}

}

/**

 * 异步请求的Servlet

 */

@WebServlet(urlPatterns="/AsyncServlet",asyncSupported=true)

public class AsyncServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		AsyncContext context = request.startAsync(request, response);

		context.start(new MyRunnable(context));

		for(int i = 1;i<=10;i++){

			System.out.println(i);

			try {

				Thread.sleep(500);

			} catch (InterruptedException e) {

				e.printStackTrace();

			}

		}

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doGet(request, response);

	}

}

class MyRunnable implements Runnable{

	private AsyncContext context;

	public MyRunnable(AsyncContext context) {

		this.context = context;

	}

	@Override

	public void run() {

		for(char i='a';i<='z';i++){

			try {

				context.getResponse().getWriter().println(i);

				Thread.sleep(100);

			} catch (Exception e) {

				e.printStackTrace();

			}

		}

	}

}