Servlet实现简单的下载图片

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.OutputStream;

public class DownLoadServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取文件下载路径
        String realPath = "C:\\Users\\37407\\Desktop\\beauty.jpg";
        System.out.println(realPath);//检查路径是否正确

        //2.设置文件名称
        String fileName = realPath.substring(realPath.lastIndexOf("\\") + 1);
        System.out.println(fileName);

        //3.设置响应头浏览器支持我们进行下载（不需要记，百度即可）,注意最后文件名字的修改
        resp.setHeader("Content-Disposition","attachment;filename=" + fileName);

        //4.获取输入流
        FileInputStream fileInputStream = new FileInputStream(realPath);

        //5.创建缓冲区
        int len = 0;
        byte[] buffer = new byte[1024];

        //6.创建输出流，这里用到了response响应
        ServletOutputStream outputStream = resp.getOutputStream();

        //7.将输入流读入缓存区，并输出
        while((len = fileInputStream.read(buffer)) != -1){
            //将缓冲区中的流读出来
            outputStream.write(buffer,0,len);
        }
    }
}