服务器端实现文件下载功能代码

package com.cn;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Download
 */
@WebServlet("/Download")
public class Download extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Download() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        String name = "aaa.*";// 文件名
        String uploadPath = UploadFileHelper.getRepositoryPath() + "//";// 文件来源

        String filePath = name;
        String fileName = name;
          //处理文件名包含中文，浏览器乱码
        if (request.getHeader("User-Agent").toLowerCase().indexOf("firefox") > 0) {
            fileName = new String(fileName.getBytes("UTF-8"), "ISO8859-1");// firefox浏览器
        } else {
            if (request.getHeader("User-Agent").toUpperCase().indexOf("MSIE") > 0) {
                fileName = URLEncoder.encode(fileName, "UTF-8");// IE浏览器
            }
        }
        response.setContentType("text/plain");
        response.setHeader("Location", fileName);
        response.reset();
        response.setHeader("Cache-Control", "max-age=0");
        response.setHeader("Content-Disposition", "attachment; filename="
                + fileName);
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        OutputStream fos = null;
        InputStream fis = null;
        filePath = uploadPath + filePath;
        fis = new FileInputStream(filePath);
        bis = new BufferedInputStream(fis);
        fos = response.getOutputStream();
        bos = new BufferedOutputStream(fos);

        int bytesRead = 0;
        byte[] buffer = new byte[5 * 1024];
        while ((bytesRead = bis.read(buffer)) != -1) {
            bos.write(buffer, 0, bytesRead);// 将文件发送到客户端
        }
        bos.close();
        bis.close();
        fos.close();
        fis.close();

    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

}