resp下载文件

package com.gao;

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;

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="D:\\毕设\\javaweb_study\\response\\src\\main\\resources\\IMG_20171023_045812.jpg";  //this.getServletContext().getRealPath("/1.jpg");
        System.out.println("下载的路径为："+realPath);
        //下载的文件名是啥
        String fileName = realPath.substring(realPath.lastIndexOf("\\") + 1);
        //设置浏览器支持的
        resp.setHeader("Content-Disposition","attachment;filename"+fileName);
        //获取下载的输入流
        FileInputStream in = new FileInputStream(realPath);
        //创建缓冲区
        int len=0;
        byte[] buffer = new byte[1024];
        //获取OutputStream对象
        ServletOutputStream out = resp.getOutputStream();
        //将FileOutputStream流写入buffer，用OutputStream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);
    }
}