前段时间事情比较多,导致二月份没有记录自己的学习情况。最近接触了servlet,参考韩老师的教程自己写了一个web站点文件下载的小项目,该项目中还加入了简单的反盗链技术。

  1、首先创建一个SharedFilesServlet用于返回一个文件分享界面

 package com.hyman.view;

 import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; /**
* Servlet implementation class SharedFilesServlet
*/
public class SharedFilesServlet extends HttpServlet {
private static final long serialVersionUID = 1L; /**
* @see HttpServlet#HttpServlet()
*/
public SharedFilesServlet() {
super();
// TODO Auto-generated constructor stub
} /**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html; charset=utf-8");
PrintWriter out = response.getWriter();
out.println("<script type='text/javascript' language='javascript'>"
+ "function fileDown(obj){"
+ "var resourceName = '';"
+ "var buttonId = obj.getAttribute('id');"
+ "var eleName = buttonId.substring(0,3) + 'File';"
+ "resourceName = document.getElementsByName(eleName)[0].value;"
+ "var url = '/SharingSite/DownFileServlet?fileName=' + resourceName;"
+ "window.location.href=url;"
+ "}"
+ "</script>");
out.println("<h1>文件共享网站</h1>");
out.println("mp3资源:<input type='text' name='mp3File' />&nbsp;&nbsp;&nbsp;&nbsp;<input type='submit' value ='点击下载' id='mp3Down' onclick='fileDown(this)' /><br/>");
out.println("avi资源:<input type='text' name='aviFile' />&nbsp;&nbsp;&nbsp;&nbsp;<input type='submit' value ='点击下载' id='aviDown' onclick='fileDown(this)' /><br/>");
out.println("jpg资源:<input type='text' name='jpgFile' />&nbsp;&nbsp;&nbsp;&nbsp;<input type='submit' value ='点击下载' id='jpgDown' onclick='fileDown(this)' /><br/>");
out.println("txt资源:<input type='text' name='txtFile' />&nbsp;&nbsp;&nbsp;&nbsp;<input type='submit' value ='点击下载' id='txtDown' onclick='fileDown(this)' /><br/>");
} /**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(request, response);
} }

  2、然后创建一个控制器,来判断是否盗链,以及处理文件下载逻辑:

 package com.hyman.controller;

 import java.io.File;
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 DownFileServlet
*/
public class DownFileServlet extends HttpServlet {
private static final long serialVersionUID = 1L; /**
* @see HttpServlet#HttpServlet()
*/
public DownFileServlet() {
super();
// TODO Auto-generated constructor stub
} /**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html; charset=utf-8");
String referer = request.getHeader("Referer");
if (referer == null || !referer.startsWith("http://localhost:8080/SharingSite/")) {
response.sendRedirect("/SharingSite/AntiPirateLink");
} else {
String fileName = request.getParameter("fileName");
response.setHeader("Content-Disposition", "attachment; filename="+fileName);
String path = this.getServletContext().getRealPath("/resources/"+fileName);
FileInputStream fis = null;
OutputStream os = null;
try {
fis = new FileInputStream(new File(path));
byte buff[] = new byte[1024];
int len = 0;
os = response.getOutputStream();
while ((len = fis.read(buff)) > 0) {
os.write(buff, 0, len);
}
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException();
} finally {
if (os != null) os.close();
if (fis != null) fis.close();
}
} } /**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(request, response);
} }

  3、创建一个AntiPirateLink返回盗链提醒界面,并在10秒后自动刷新跳转到SharedFilesServlet

 package com.hyman.view;

 import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; /**
* Servlet implementation class AntiPirateLink
*/
public class AntiPirateLink extends HttpServlet {
private static final long serialVersionUID = 1L; /**
* @see HttpServlet#HttpServlet()
*/
public AntiPirateLink() {
super();
// TODO Auto-generated constructor stub
} /**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html; charset=utf-8");
PrintWriter out = response.getWriter();
out.println("<script type='text/javascript' language='javascript'>"
+ "var i = 10;"
+ "function showTime(){"
+ "if(i > 0) {document.getElementById('time').innerHTML = '请不要盗链下载... ' + i +' 秒后自动跳转到下载首页...';"
+ "i--;}"
+ "}"
+ "setInterval('showTime()',1000);"
+ "</script>");
out.println("<span id='time'></span>");
response.setHeader("Refresh", "10; url=/SharingSite/SharedFilesServlet");
} /**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(request, response);
} }

【分析】文件下载部分实现步骤:

1、response.setHeader("Content-Disposition", "attachment; filename="+fileName);在http回复消息头中的Content-Disposition中指明下文件的文件名;
2、调用this.getServletContext().getRealPath("/resources/"+fileName);函数获取到文件的全路径;
3、使用文件流FileInputStream将文件读入到服务器内存,重要要用到缓存处理,然后再调用response的getOutputStream()方法获得向客户端写文件的输出文件流;

Servlet实现web站点文件下载功能示例的更多相关文章

  1. 【Servlet】java web 文件下载功能实现

    需求:实现一个具有文件下载功能的网页,主要下载压缩包和图片 两种实现方法: 一:通过超链接实现下载 在HTML网页中,通过超链接链接到要下载的文件的地址 <!DOCTYPE html> & ...

  2. 解决springmvc中文件下载功能中使用javax.servlet.ServletOutputStream out = response.getOutputStream();后运行出异常但结果正确的问题

    问题描述: 在springmvc中实现文件下载功能一般都会使用javax.servlet.ServletOutputStream out = response.getOutputStream();封装 ...

  3. WebLech是一个功能强大的Web站点下载与镜像工具

    WebLech是一个功能强大的Web站点下载与镜像工具.它支持按功能需求来下载web站点并能够尽可能模仿标准Web浏览器的行为.WebLech有一个功能控制台并采用多线程操作. http://sour ...

  4. java web文件下载功能实现 (转)

    http://blog.csdn.net/longshengguoji/article/details/39433307 需求:实现一个具有文件下载功能的网页,主要下载压缩包和图片 两种实现方法: 一 ...

  5. 启动Nginx目录浏览功能及 让用户通过用户名密码认证访问web站点

    一.启动Nginx目录浏览功能  [root@abcdocker extra]# cat w.conf server { listen 80; server_name IP地址; location / ...

  6. 为Windows Azure Web站点添加MIME类型解决文件下载失败的问题

    这几天在倒腾Autodesk 360 Viewer,前面的文章也介绍过了,这将是一个全新的在线模型浏览工具.我做了个实验,把A360Viewer放在一个web 站点,然后发布到Windows Azur ...

  7. Java精选笔记_Tomcat开发Web站点

    Tomcat开发Web站点 Web开发的相关知识 B/S架构和C/S架构 C/S架构是Client/Server的简写,也就是客户机/服务器端的交互.常见应用 : QQ. 迅雷. 360. 旺旺等 B ...

  8. ASP.NET MVC with Entity Framework and CSS一书翻译系列文章之第一章:创建基本的MVC Web站点

    在这一章中,我们将学习如何使用基架快速搭建和运行一个简单的Microsoft ASP.NET MVC Web站点.在我们马上投入学习和编码之前,我们首先了解一些有关ASP.NET MVC和Entity ...

  9. JAVA文件下载功能问题解决日志

    今天给报告系统做了个下载功能,遇到了挺多问题,通过查资料一一解决了. 1.首先遇到的问题是:java后台的输出流输出之后,没有任何报错,浏览器端不弹出保存文件的对话框,原本是ajax请求到后台的con ...

随机推荐

  1. javascript 制作的美化select,利用cookie保存选择

    可以看一下动画 下面是代码 <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> ...

  2. block的简单使用:点击按钮在另一个控制器内调用block内的代码

    1.自定义一个继承于UIButton的按钮 2.声明block: 返回值类型   函数名  参数列表 typedef void (^ButtonBlock)(UIButton *); @interfa ...

  3. XML&nbsp; XmlDocument

    1.SelectSingleNode(xPath)  xPxth:xml/cam/type  一层一层递进

  4. [改善Java代码]用整数类型处理货币

    建议22:用整数类型处理货币. public class Client { public static void main(String[] args) { System.out.println(&q ...

  5. ubuntu qt :-1: error cannot find lgl

    安装package "libgl1-mesa-dev": sudo apt-get install libgl1-mesa-dev 参考文献: Qt: can't find -lG ...

  6. crontab执行java命令失效

    一.我们常常碰到在shell下执行某个命令能够成功,比如执行一个java程序: java -jar /home/opscoder/topo-audit.jar,但是在crontab下执行会失败. co ...

  7. CSS3如何实现2D转换和3D转换,他们有何区别

    CSS3中2D3D技术的发展,带来了更丰富的视觉效果~他们的实现机理是怎样的呢? 1定义 2D: 能够对元素进行移动,缩放,转动,拉长或拉伸. 3D: 允许对元素进行格式化,在三维空间进行操作.元素改 ...

  8. django 学习-10 Django多对多关系模型

    1.vim blog/models.py class   Author(models.Model): name = models.CharField(max_length=30) def unicod ...

  9. beeline连接hive server遭遇MapRedTask (state=08S01,code=1)错误

    采用beeline连接hive server是遭遇到如下错误: 5: jdbc:hive2://bluejoe0/default> select * from hive_triples wher ...

  10. HTML5新特性之WebNotifications

    Web Notifications是HTML5中一个令人欣喜的新特性,它支持开发者配置和显示桌面通知,为用户提供更好的体验,最令人称赞的是,即使用户忙于其他工作时也可以收到来自页面的消息通知,例如一个 ...