Response实现文件下载的java代码
//这是实现下载类（servlet），具体思路代码如下：//也可连接数据库package com.message;import javax.servlet.*;import javax.servlet.http.*;import java.io.*;import java.util.*;public class FileDownServlet extends HttpServlet { private static final String CONTENT_TYPE = "text/html; charset=GBK"; //Initialize global variables public void init() throws ServletException { } //Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType(CONTENT_TYPE); //得到下载文件的名字 //String filename=request.getParameter("filename"); //解决中文乱码问题 String filename=new String(request.getParameter("filename").getBytes("iso-8859-1"),"gbk"); //创建file对象 File file=new File("F:\\book\\WebRoot\\"+filename); //设置response的编码方式 response.setContentType("application/x-msdownload"); //写明要下载的文件的大小 response.setContentLength((int)file.length()); //设置附加文件名 // response.setHeader("Content-Disposition","attachment;filename="+filename); //解决中文乱码 response.setHeader("Content-Disposition","attachment;filename="+new String(filename.getBytes("gbk"),"iso-8859-1")); //读出文件到i/o流 FileInputStream fis=new FileInputStream(file); BufferedInputStream buff=new BufferedInputStream(fis); byte [] b=new byte;//相当于我们的缓存 long k=0;//该值用于计算当前实际下载了多少字节 //从response对象中得到输出流,准备下载 OutputStream myout=response.getOutputStream(); //开始循环下载 while(k<file.length()){ int j=buff.read(b,0,1024); k+=j; //将b中的数据写到客户端的内存 myout.write(b,0,j); } //将写入到客户端的内存的数据,刷新到磁盘 myout.flush(); } //Process the HTTP Post request public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } //Clean up resources public void destroy() { }}
//这是javabean写法 ，主要是实现和数据库连接的，如果没有连接数据库，就可直接不要这package com;public class MessageBean { private String Message; public String getMessage() {return Message; } public void setMessage(String message) {Message = message; }}
//HTML页面载入写发，也可连接数据库（案例代码也在）<%@ page language="java" import="java.util.*,com.message.*" pageEncoding="gbk"%><jsp:directive.page import="com.MessageBean;"/><%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>My JSP 'book.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --></head> <body> <!--<a href="java.rar">5.1下载书--java</a> <br>--> <%//Vector vv=(Vector)session.getAttribute("message");//for(int i=0;i<vv.size();i++){ // MessagesBean mb=(MessagesBean)vv.get(i); // out.println("<tr>"); // out.println("<td>"+mb.getSender()+"</td>"); // out.println("<td>"+mb.getMess_time()+"</td>"); // out.println("<td>"+mb.getGeter()+"</td>"); // out.println("<td>"+mb.getMess_content()+"</td>");String filename=null;session.setAttribute("java.rar",filename); //取得文件名 // filename=getFilepath().substring(mb.getFilepath().lastIndexOf("\")+1); out.println("<td><a href=FileDownServlet?filename=java.rar>5.1下载书--java</a></td>");//java.rar这个可以改成变量 out.println("<td><a href=FileDownServlet?filename=dos.rar>dos视频教程</a></td>"); out.println("<td><a href=FileDownServlet?filename=常用DOS命令.rar>常用DOS命令</a></td>"); out.println("</tr>"); // }%></body></html>
//这是web.xml配置文件，这很重要，不然，很难实现哦<?xml version="1.0" encoding="UTF-8"?><web-app version="2.4"xmlns="http://java.sun.com/xml/ns/j2ee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/j2eehttp://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"><servlet> <description>This is the description of my J2EE component</description> <display-name>This is the display name of my J2EE component</display-name> <servlet-name>FileDownServlet</servlet-name> <servlet-class>com.message.FileDownServlet</servlet-class></servlet><servlet-mapping> <servlet-name>FileDownServlet</servlet-name> <url-pattern>/FileDownServlet</url-pattern></servlet-mapping></web-app>
本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/zhuseahui/archive/2008/11/26/3381704.aspx
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