没使用UploadFile实现文件下载Demo源码
1.首先本小姐很久没写代码，很多东西其实都忘的差不多，特别是Html的一些标签和js更是忘得一塌糊涂，由于这次我们公司要做个上传下载的web服务器，改服务器是跟android客户端提供数据的，也就是说这个ftpweb下载服务器主要是android端提供文件下载等服务的，但是我用jsp页面做了个demo，原理差不多，只是跟android端传递的不是下载文件数据，而是包含下载路径的下载文件信息，以下是我写的小demo；
2.下面是Jsp页面代码：
<script type="text/javascript">
function xiaozhukuaipaoOnclick(){
var filename = "小猪快跑13.01.apk";
document.getElementById("form").action="xiazai?fileName="+encodeURI(encodeURI(filename));
document.getElementById("form").submit();
}
function xiaoyazhiOnclick(){
var filename = "小鸭子.APK" ;
document.getElementById("form").action="xiazai?fileName="+encodeURI(encodeURI(filename));
document.getElementById("form").submit();
// document.forms[0].action + =("&fileName="+filename) ;
// document.forms[0].submit();
}
function GoLiveOnclick(){
var filename ="GoLive TV.11.02.apk";
// alert(document.forms[0].action);
// document.forms[0].action+("&fileName="+filename) ;
//document.forms[0].action="xiazai?fileName="+filename" ;
// document.forms[0].submit();
document.getElementById("form").action="xiazai?fileName="+encodeURI(encodeURI(filename));
document.getElementById("form").submit();
}
</script>
<form id="form" enctype="multipart/form-data" method="post">
<li><span>小猪快跑游戏.APK </span>
<input type="button" value="下载" name="xiaozhukuaipao" id="xiaozhukuaipao" onclick="xiaozhukuaipaoOnclick()"> </li>
<li><span>小鸭子.APK </span>
<input type="button" value="下载" name="xiaoyazhi" id="xiaoyazhi" onclick="xiaoyazhiOnclick()"> </li>
<li><span> GoLive TV.11.02.apk </span>
<input type="button" value="下载" name="GoLive" id="GoLive" onclick="GoLiveOnclick()"> </li>
</form>
3.下面是我的servlet类：
package download.control;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class DownLoadControlServlet extends HttpServlet {
private static final long serialVersionUID = 1l;
private DownLoadControlServlet downLoadControlServlet ;
public void init() throws ServletException{
System.out.println("DownLoadControlServlet init()?????..");
}
public void init(ServletConfig config) throws ServletException{
super.init(config);
System.out.println("DownLoadControlServlet Config()");
}
public void doGet(HttpServletRequest req,HttpServletResponse resp) throws IOException,ServletException{
System.out.println(req+"---"+resp);
this.doPost(req, resp) ;
System.out.println("DownLoadControlServlet doGet()");
}
public void doPost(HttpServletRequest req,HttpServletResponse resp) throws IOException,ServletException{
System.out.println(req+"---"+resp);
HttpServletResponse response = resp;
HttpServletRequest request = req;
System.out.println("DownLoadControlServlet doGet()");
// String fileName = req.getParameter("fileName");
// PrintWriter printWriter = new PrintWriter() ;
/*if(fileName == null || fileName == ""){
System.out.print("用户请求下载的文件不存在");
}
*/
//将文件流写入浏览器
OutputStream outputStream = resp.getOutputStream();
ServletContext servletContext=req.getSession().getServletContext();
String fileName =req.getParameter("fileName") ;
File file = new File(servletContext.getRealPath("/WEB-INF/downLoad/"), fileName);
// File file =new File("D:/download/res/" , "fileName");
System.out.println(file.getPath()+"-------");
resp.setHeader("Content-disposition","attachment; filename="+fileName);
resp.setContentType("application/vnd.ms-excel;charset=GBK");
resp.setBufferSize(1024);
resp.setHeader("Cache-Control","no-cache"); //HTTP 1.1
resp.setHeader("Pragma","no-cache"); //HTTP 1.0
resp.setDateHeader ("Expires", 0); //prevents caching at the proxy server
if (file.exists()) {
FileInputStream fileInputStream = new FileInputStream(file);
byte[] b = new byte[1024];
int length;
while ((length = fileInputStream.read(b)) != -1) {
outputStream.write(b, 0, length);
outputStream.flush();
}
}
else {
System.out.println("下载的文件不存在");
}
}
public void destroy(){
System.out.println("Servlet destroy()....");
}
}
4.从代码中可以看出我的下载文件是放在webInfo下面的downLoad文件下面，
5.在web.xml配置servlet应该都会，但是还是写上吧
<servlet>
<servlet-name>DownLoadControlServlet</servlet-name>
<servlet-class>download.control.DownLoadControlServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>DownLoadControlServlet</servlet-name>
<url-pattern>/xiazai</url-pattern>
</servlet-mapping>
