package?com.upload.servlet;

import?java.io.File;
import?java.io.IOException;

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;
import?javax.servlet.http.HttpSession;

public?class?DownloadServlet?extends?HttpServlet?{
	static?final?private?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（“text/html;?charset=UTF-8“）;
		HttpSession?session?=?request.getSession（）;
		//?要下載的文件??
		//?之所以這樣處理，主要是因為文件名的中文化問題，這樣處理的話，中文文件名也會正常顯??
		String?downloadfile?=?new?String（（request.getParameter（“downFile“））.getBytes（“iso8859-1“）?“UTF-8“）;
		//String?downloadfileName?=??new?String（（request.getParameter（“downName“））.getBytes（“iso8859-1“）?“UTF-8“）;//request.getParameter（“downName“）;
		String?app=request.getParameter（“app“）;
		String?downloadfileName=““;
		if（“app“.equals（app））{
			downloadfileName?=?“改薄App“;
		}else{
			downloadfileName?=?request.getParameter（“downName“）;
		}
		
		ServletContext?context?=?getServletContext（）;
		ServletConfig?config?=?getServletConfig（）;
?
		//?獲取要下載文件所在的目錄，這里是對應于服務器上的物理路徑
		//?目錄的格式是這樣??
		//?根目錄（WEB主目錄所對應的實際物理目錄）
		//?+虛擬目錄（下載文件存放的子目錄）
		//String?downloadpath?=?context.getRealPath（File.separator）+?config.getInitParameter（“downloadPath“）?+?File.separator;
		String?downloadpath?=?context.getRealPath（File.separator）;
		//?構建下載文件的對??
		java.io.File?file?=?new?java.io.File（downloadpath?+?downloadfile）;
		
		if（!file.exists（））{
			response.sendRedirect（“no_file.jsp“）;
		}else{
			//?獲得文件的長??
			long?filesize?=?file.length（）;
			//?設置輸出格式
			String?fileType=“.“+getFiletype（downloadfile）;
			String?type=?““;
			
			if（downloadfileName.lastIndexOf（“.“）?!=?-1）{
				type?=?downloadfileName.substring（downloadfileName.lastIndexOf（“.“）?downloadfileName.length（））;
			}
			
			response.addHeader（“content-type“?“application/x-msdownload;“）;
			String?title=downloadfileName+fileType;
			String?finalFileName=““;
			if（type!=null&&fileType.equals（type））{
				response.addHeader（“Content-Disposition“?“attachment;?filename=“?+?new?String（downloadfileName.getBytes（“gb2312“）?“iso8859-1“））;
			}else{
				String?agent?=?request.getHeader（“User-Agent“）;
				boolean?isMSIE?=?（agent?!=?null?&&?agent.indexOf（“MSIE“）?!=?-1）;
				if（?isMSIE?）{
					finalFileName?=?java.net.URLEncoder.encode（title“UTF8“）;
				}else{
					finalFileName?=?new?String（title.getBytes（“UTF-8“）?“ISO-8859-1“）;
				}
				response.addHeader（“Content-Disposition“?“attachment;filename=“+finalFileName）;
				//response.addHeader（“Content-Disposition“?“attachment;?file

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2016-09-08?17:06??掃描二維碼下載app\
?????文件???????98185??2016-09-08?17:06??掃描二維碼下載app\掃碼下載代碼說明.pdf
?????目錄???????????0??2016-09-08?16:56??掃描二維碼下載app\源代碼\
?????文件????????4496??2016-09-08?13:55??掃描二維碼下載app\源代碼\DownloadServlet.java
?????文件????????2845??2016-09-08?16:45??掃描二維碼下載app\源代碼\download_apk.jsp
?????文件??????????80??2016-09-08?16:56??掃描二維碼下載app\說明.txt