web下载

public class FileServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取写在文件路径
         String realPath="D:\\ideaworkplace\\JAVAWEB01\\response\\src\\main\\resource\\jinghua.mp4";
        System.out.println("下载路径："+realPath);
        //2.下载文件名是什么？
        String fileName=realPath.substring(realPath.lastIndexOf("\\")+1);
        //3.设置浏览器支持(Content-Disposition)我们需要的东西，中文文件URLEncoder.encode编码否则可能乱码
        resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
        //4.获取下载文件流
        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);
    }
}