Servlet下载文件

1.创建index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	让tomcat的默认servlet去提供下载：<br>
	<a href="download/aa.jpg">aa.jpg</a><br>
	<a href="download/bb.txt">bb.txt</a><br>
	<a href="download/cc.rar">cc.rar</a><br>

	<br>手动编码提供下载。：<br>
	<a href="DownLoad?filename=aa.jpg">aa.jpg</a><br>
	<a href="DownLoad?filename=bb.txt">bb.txt</a><br>
	<a href="DownLoad?filename=cc.rar">cc.rar</a><br>
	
</body>
</html>

2.创建Servlet DownLoad

package com.hbxy.rick;

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

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

public class DownLoad extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 1. 获取要下载的文件名字 aa.jpg --- inputStream
		String fileName = request.getParameter("filename");
		// 2. 获取这个文件在tomcat里面的绝对路径地址
		String path = getServletContext().getRealPath("download/" + fileName);
		// 让浏览器收到这份资源的时候， 以下载的方式提醒用户，而不是直接展示。
		response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
		
		//response.setStatus(302);
		//response.setHeader(Location, "login_success.html");

		// response.sendRedirect("login_success.html");

		// 3. 转化成输入流
		InputStream is = new FileInputStream(path);
		OutputStream os = response.getOutputStream();

		int len = 0;
		byte[] buffer = new byte[1024];
		while ((len = is.read(buffer)) != -1) {
			os.write(buffer, 0, len);
		}
		os.close();
		is.close();
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

}

测试

Servlet下载文件

下载成功！！！！！