package org.servlet;

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

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

import org.util.UploadUtil;

/**
 * 用于文件下載處理的Servlet
 * @author 沈元杰
 *
 * @date 2008-5-6
 */
public class DownloadFileServlet extends HttpServlet {
	private static final long serialVersionUID = 56890894234786L;

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, java.io.IOException {

		// 要下載的文件名		
		String filename=request.getParameter("file");	

		// 文件真實地址
		String filePathname = UploadUtil.getUploadPath()+filename;		

		// 設置內容格式
		response.setContentType("text/x-msdownload");
		
		// 設置文件頭信息
		response.setHeader("Content-Disposition","attachment; filename=" + filename + "");
		
		OutputStream outputStream = response.getOutputStream();
		InputStream inputStream = new FileInputStream(filePathname);
		byte[] buffer = new byte[1024];
		int i = -1;
		while ((i = inputStream.read(buffer)) != -1) {
			outputStream.write(buffer, 0, i);
		}
		outputStream.flush();
		outputStream.close();
		inputStream.close();
		outputStream = null;
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, java.io.IOException {
		doPost(request, response);
	}
}