package org.hqu.production_ms.util;

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

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;

import org.hqu.production_ms.exception.CustomException;

public class DownloadUtil {
	
	/**
	 * @param filePath 要下载的文件路径
	 * @param returnName 返回的文件名
	 * @param response HttpServletResponse
	 * @param delFlag 是否删除文件
	 */
	public void download(String filePath,String returnName,HttpServletResponse response,boolean delFlag) throws Exception{
		this.prototypeDownload(new File(filePath), returnName, response, delFlag);
	}

	/**
	 * @param file 要下载的文件
	 * @param returnName 返回的文件名
	 * @param response HttpServletResponse
	 * @param delFlag 是否删除文件
	 */
	protected void download(File file,String returnName,HttpServletResponse response,boolean delFlag) throws Exception{
		this.prototypeDownload(file, returnName, response, delFlag);
	}
	
	/**
	 * @param file 要下载的文件
	 * @param returnName 返回的文件名
	 * @param response HttpServletResponse
	 * @param delFlag 是否删除文件
	 */
	public void prototypeDownload(File file,String returnName,HttpServletResponse response,boolean delFlag) throws Exception{
		// 下载文件
		FileInputStream inputStream = null;
		ServletOutputStream outputStream = null;
		if(!file.exists()){
			throw new CustomException("文件不存在！");
		}
		try {
			response.reset();
			//设置响应类型	PDF文件为"application/pdf"，WORD文件为："application/msword"， EXCEL文件为："application/vnd.ms-excel"。  
			response.setContentType("application/octet-stream;charset=utf-8");

			//设置响应的文件名称,并转换成中文编码
			//returnName = URLEncoder.encode(returnName,"UTF-8");
			returnName = response.encodeURL(new String(returnName.getBytes(),"iso8859-1"));	//保存的文件名,必须和页面编码一致,否则乱码
			
			//attachment作为附件下载；inline客户端机器有安装匹配程序，则直接打开；注意改变配置，清除缓存，否则可能不能看到效果
			response.addHeader("Content-Disposition",   "attachment;filename="+returnName);  
			
			//将文件读入响应流
			inputStream = new FileInputStream(file);
			outputStream = response.getOutputStream();
			int length = 1024;
			int readLength=0;
			byte buf[] = new byte[1024];
			readLength = inputStream.read(buf, 0, length);
			while (readLength != -1) {
				outputStream.write(buf, 0, readLength);
				readLength = inputStream.read(buf, 0, length);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				outputStream.flush();
			} catch (IOException e) {
				e.printStackTrace();
			}
			try {
				outputStream.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			try {
				inputStream.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			//删除原文件
			
			if(delFlag) {				
				file.delete();
			}
		}
	}

	/**
	 * by tony 2013-10-17
	 * @param byteArrayOutputStream 将文件内容写入ByteArrayOutputStream
	 * @param response HttpServletResponse	写入response
	 * @param returnName 返回的文件名
	 */
	public void download(ByteArrayOutputStream byteArrayOutputStream, HttpServletResponse response, String returnName) throws IOException{
		response.setContentType("application/octet-stream;charset=utf-8");
		returnName = response.encodeURL(new String(returnName.getBytes(),"iso8859-1"));			//保存的文件名,必须和页面编码一致,否则乱码
		response.addHeader("Content-Disposition",   "attachment;filename=" + returnName);  
		response.setContentLength(byteArrayOutputStream.size());
		
		ServletOutputStream outputstream = response.getOutputStream();	//取得输出流
		byteArrayOutputStream.writeTo(outputstream);					//写到输出流
		byteArrayOutputStream.close();									//关闭
		outputstream.flush();											//刷数据
	}
}
