servlet实现文件下载_servlet implementation class download-优快云博客

本文链接：https://blog.youkuaiyun.com/RollingInTheDeepc/article/details/78370606

本文介绍了一个使用Java Servlet实现的文件下载服务。该服务通过HTTP请求接收文件名参数，然后从服务器读取指定文件并将其发送给客户端进行下载。文章详细展示了如何设置响应头来控制文件的下载行为。

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package com.download;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet implementation class RealDownload
*/
public class RealDownload extends HttpServlet {
private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public RealDownload() {
        super();
        // TODO Auto-generated constructor stub
    }

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  //文件内容的下载
  //1.获取文件的地址
  String file=request.getParameter("name");
  //获取文件的地址
  String path=this.getServletContext().getRealPath(file);
  //设置写入到客户端的MIME类型
  response.setContentType(this.getServletContext().getMimeType(file));
//设置文件以插件的形式打开
  response.setHeader("Content-disposition", "attachment,filename="+file);
//文件以字节流的形式写入到客户端
  FileInputStream in=new FileInputStream(path);
//文件的内容写入到客户端
  int len=0;
  byte[] by=new byte[1024];
  OutputStream out=response.getOutputStream();
  while((len=in.read(by))>0){
   out.write(by,0,len);
   out.flush();
  }
  in.close();
  out.close();
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}

}