package com.shengke.servlet;

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

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

/**
 * Servlet implementation class DownloadServlet
 */
public class DownloadServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       


	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//获取文件下载路径,自己可是根据需求修改，一般是你的资源服务的目录
//		String path = getServletContext().getRealPath("/") + "images/";
		String path = "/home/shengke/workspace/fileSCXZ/WebContent/images/";
		String filename = request.getParameter("filename");
		File file = new File(path + filename);
		//判断文件是否存在
		if(file.exists()){
			//设置相应类型application/octet-stream（文件下载类型）
			response.setContentType("application/x-msdownload");
			//设置头信息（以附件形式，打开下载文件）
			response.setHeader("Content-Disposition", "attachment;filename=\"" + filename + "\"");
			//获取输入流输出流
			InputStream inputStream = new FileInputStream(file);
			ServletOutputStream ouputStream = response.getOutputStream();
			//循环把输入流写入输出流
			byte b[] = new byte[1024];
			int n ;
			while((n = inputStream.read(b)) != -1){
				ouputStream.write(b,0,n);
			}
			//关闭流、释放资源
			ouputStream.close();
			inputStream.close();
			
			
		}else{
			request.setAttribute("errorResult", "文件不存在下载失败！");
			RequestDispatcher dispatcher = request.getRequestDispatcher("jsp/index.jsp");
			dispatcher.forward(request, response);
		}
		
		
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request,response);
	}

}