JavaWeb Request下载文件实例

package com.zrc.response;

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;

@WebServlet("/fs")
public class FileServlet 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 = "E:\\Program\\Java Project\\javaweb-02-servlet\\response-01\\target\\classes\\哈哈哈.png";
        System.out.println(realPath);
        //2.获取要下载文件的文件名
        String fileName = realPath.substring(realPath.lastIndexOf("\\") + 1);
        //3.设置想让浏览器能够支持下载我们需要的东西
        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 {
    
    
        doGet(req, resp);
    }
}