Ext+servlet上传

import javax.servlet.Servlet;

import javax.servlet.ServletInputStream;

import javax.servlet.http.*;



import java.io.*;



public class UploadFile extends HttpServlet implements Servlet {

	public ServletInputStream sis = null;// 输入流

	private byte[] b = new byte[4096];// 字节流存放数组

	private byte[] buff = new byte[1024];



	public void doPost(HttpServletRequest request, HttpServletResponse response) {

		try {

			PrintWriter out = response.getWriter();

			String systemPath = request.getRealPath("/");// 当前项目路径

			sis = request.getInputStream();

			int a = 0;

			int k = 0;

			String path = "";

			while ((a = sis.readLine(b, 0, b.length)) != -1) {

				path = new String(b, 0, a);

				if ((k = path.indexOf("filename=")) != -1) {

					path = path.substring(k + 10);

					k = path.indexOf("/"");

					path = path.substring(0, k);

					int c = path.lastIndexOf("//");

					String fileName = path.substring(c + 1);// 文件名

					int f = fileName.lastIndexOf(".");

					String dat = fileName.substring(f + 1);// 扩展名

					if (!dat.equals("raq") && dat != "raq") {// 如果扩展名字不是raq.不允许上传

						out.print("{failure:true,info:'5'}");// 5表示扩展名不对

						return;

					}

					File fileReadin = new File(path);// 上传过来的文件

					if (!fileReadin.exists()) {// 判断文件是否存在

						out.print("{failure:true,info:'0'}");// 0表示文件不存在

						return;

					} else {

						File fileOutput = new File(systemPath + "reportFiles//"

								+ fileName);// 输出的文件

						UploadFile.copyFile(path, systemPath + "reportFiles//"

								+ fileName, response);// 把上传的文件copy给新建的文件

						out.print("{success:true,info:'1'}");// 1表示上传成功

						return;

					}



				}



			}

		} catch (Exception e) {

			e.printStackTrace();

		}

	}



	public void doGet(HttpServletRequest request, HttpServletResponse response) {

		doPost(request, response);

	}



	public static boolean copyFile(File filefrom, File fileto, boolean rewrite,

			HttpServletResponse response) {

		try {

			PrintWriter out = response.getWriter();

			if (!filefrom.canRead()) {

				out.print("{success:true,info:'4'}");// 4表示无法读取上传文件

				return false;

			}

			FileInputStream fosfrom = new FileInputStream(filefrom);

			FileOutputStream fosto = new FileOutputStream(fileto);

			byte bt[] = new byte[1024];

			int c;

			while ((c = fosfrom.read(bt)) > 0) {

				fosto.write(bt, 0, c);

			}

			fosfrom.close();

			fosto.close();

			return true;

		} catch (Exception ex) {

			ex.printStackTrace();

			return false;

		}



	}



	public static boolean copyFile(String from, String to,

			HttpServletResponse response) {

		File filefrom = new File(from);

		File fileto = new File(to);

		return copyFile(filefrom, fileto, true, response);

	}

}
     不知道杂说.自己看代码吧.