servlet 实现下载文件

时间:2024-10-21 12:36:50

servlet:

public class UpAndDownServlet extends HttpServlet {

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

String type = request.getParameter("type");

if("down".equals(type)){

File file = new File("D:\\test\\44444.png");

FileInputStream is = new FileInputStream(file);

BufferedInputStream bs = new BufferedInputStream(is);

ServletOutputStream os = response.getOutputStream();

BufferedOutputStream bos = new BufferedOutputStream(os);

String date = new SimpleDateFormat("yyyy-HH-dd").format(new Date());

String fileName = date + ".jpg";

response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");

byte[] len = new byte[1024*2];

int read = 0;

while((read=is.read(len)) != -1){

bos.write(len, 0, read);

System.out.println("read---"+read);

}

bos.flush();

bos.close();

is.close();

}

}

}

怎样实现文件下载

要实现文件下载,我们仅仅须要设置两个特殊的对应头,它们是什么头?假设文件名称带中文,该怎样解决?

两个特殊的对应头:

----Content-Type:       application/octet-stream

----Content-Disposition: attachment;filename=aaa.zip

比如:

response.setContentType("image/jpeg");response.setHeader("Content- Disposition","attachment;filename=Bluehills.jpg");

页面:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>



<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

    <base href="<%=basePath%>">

    <title>down</title>

  </head>

  <body>

    <form action="servlet/UpAndDownServlet?type=down" method="post">

    <input type="submit" value="下载">

    </form>

  </body>

</html>