Servlet实现文件下载

文件下载

package com.ding.servlet;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;

/**
 * @Description 下载
 * @Author 丁帅帅
 * @Date 21/08/11 19:53
 * @Version 1.0
 */
@WebServlet("/down")
public class FileDown extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取下载文件的路径
        String realPath="D:\\IdeaProjects\\javaweb-upload\\src\\main\\webapp\\111.png";
        System.out.println("下载文件的路径:"+realPath);
        //2.下载文件名
        String fileName = realPath.substring(realPath.lastIndexOf("\\")+1);
        // 3. 设置想办法让浏览器能够支持(Content-Disposition)下载我们需要的东西,中文文件名URLEncoder.encode编码，否则有可能乱码
        resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
        //4.获取下载文件的输入流
        FileInputStream in = new FileInputStream(realPath);
        //5.创建缓冲区
        int len=0;
        byte [] buffer = new byte[1024];
        // 6. 获取OutputStream对象
        ServletOutputStream out = resp.getOutputStream();
        // 7. 将FileOutputStream流写入到buffer缓冲区,使用OutputStream将缓冲区中的数据输出到客户端！
        while ((len=in.read(buffer))>0){
            out.write(buffer,0,len);
        }

        in.close();
        out.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        super.doGet(req, resp);
    }
}


<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>下载页面</title>
</head>
<body>
<form action="/down">
    <input type="submit" value="下载">
</form>

</body>
</html>
posted @ 2021-08-11 21:29  丁帅帅dss  阅读(160)  评论(0)    收藏  举报