视频和图片下载不成报告500错误

问题遇到的现象和发生背景

视频和图片下载出现问题

问题相关代码，请勿粘贴截图


package cn.itcast.web.download;

import javax.servlet.ServletContext;
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.FileOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
@WebServlet("/downloadServlet")
public class DownloadServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    this.doPost(req,resp);
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//    1获取请求参数，文件名称
        String filename = req.getParameter("filename");
//    2使用字节输入流将文件加载到内存
//        2.1找到文件服务器路径
        ServletContext servletContext = this.getServletContext();

        String realPath = servletContext.getRealPath("/img/" + filename);
//  2.2用字节输入流
        FileInputStream fis=new FileInputStream(realPath);
//        3设置response的响应头操作 content-type
        String mimeType = servletContext.getMimeType(filename);//获取mime的类型
        resp.setHeader("content-type",mimeType);
//        设置另一个响应头 context-disposition
        resp.setHeader("Content-Disposition","attachment;filename="+filename);
//        4将输入流数据写到输出流数据
        ServletOutputStream sos=resp.getOutputStream();
        byte[] buff=new byte[1024 * 8];
        int len=0;
        while ((len=fis.read(buff))!=-1){
            sos.write(buff,0,len);
        }
        fis.close();


    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<a href="/day14/img/1.jpg" download>图片</a>
<a href="/day14/img/Eclipse.mp4" download>图片</a>
<hr>
<a href="/day14/downloadServlet?filename=1.jpg" download>图片</a>
<a href="/day14/downloadServlet?filename=Eclipse.mp4" download>视频</a>

</body>
</html>

运行结果及报错内容

不能够下载以及报错500

我的解答思路和尝试过的方法

修改路径和debug

我想要达到的结果

能够下载视频和图片

远程解决了望采纳谢谢