实现文件的下载

1.创建·download.jsp
<%@page import=“java.net.URLEncoder”%>
<%@ page language=“java” contentType=“text/html; charset=UTF-8”
pageEncoding=“UTF-8”%>

文件下载

文本下载

2.创建DownloadServlet package com.bookstore.servlet;

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

  /**

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

  /**

  • @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse

  •  response)
    

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

   // 响应的字符编码,对中文乱码进行处理
   response.setContentType("text/html;charset=utf-8");
  
   response.setCharacterEncoding("utf-8");
   request.setCharacterEncoding("utf-8");
  
   // 获取下载文件名称
   String filename = request.getParameter("filename");
   System.out.println("filename=" + filename);
  
   // 下载文件所在的位置
   String folder = "/bookcover/";
   // 通知浏览器以下载的方式打开
   response.addHeader("Content-Type", "application/octet-stream");
  
   response.addHeader("Content-Disposition", "attachment;filename="
   		+ URLEncoder.encode(filename, "utf-8"));
   // 通过文件流读取文件
   InputStream in = getServletContext().getResourceAsStream(
   		folder + filename);
   // 获取response对象的输出流
   OutputStream out = response.getOutputStream();
   byte[] buffer = new byte[1024];
   int len;
   // 循环取出流中的数据,从0开始，读到它的实际字节流
   while ((len = in.read(buffer)) != -1) {
   	out.write(buffer, 0, len);
  
   }
  

  }

  protected void doPost(HttpServletRequest request,
  HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub

   doGet(request, response);
  

  }

}