Java实现文件下载

JavaWeb实现文件的下载

代码编写：

package com.rong.servlet;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
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.io.InputStream;
import java.net.URLEncoder;

//文件下载
public class FileDown extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.要获取下载文件的路径
        String path = "D://Projects//IdeaProjects//javaweb-01-servlet//response//target//classes//Sea.jpg";
        //2.获取下载的文件名
        String filename = path.substring(path.lastIndexOf("//") + 1);
        //3.让浏览器能够支持下载文件，中文名有可能出现乱码(所以要将文件名转为UTF-8格式)
        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(path);
        //5.创建buffer缓冲区
        int len =0;
        byte[] buffer = new byte[1024];
        //6.获取OutputStream对象
        ServletOutputStream out = resp.getOutputStream();
        //7.将FileOutputStream写入缓冲区，使用OutputStream将缓冲区的内容写到客户端！
        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 {
        doGet(req, resp);
    }
}