如果用servlet返回文件流，用的是机房宽带

 

ServletOutputStream out = response.getOutputStream();

String filepath = request.getRealPath("/")+"uploadfiles/";

if(null == request.getParameter("sonFilePath")){

System.out.println("无参数");

return;

}

if(null == request.getParameter("fileName")){

System.out.println("无参数");

return;

}

String sonFilePath = new String(request.getParameter("sonFilePath").getBytes("ISO8859_1"),"GB2312").toString();

String filename = new String(request.getParameter("fileName").getBytes("ISO8859_1"),"GB2312").toString();

System.out.println("DownloadFile filepath:" + filepath+sonFilePath);

System.out.println("DownloadFile filename:" + filename);

File file = new File(filepath +sonFilePath+"/"+ filename);

if(!file.exists()){

System.out.println(file.getAbsolutePath()+"文件不存在");

return;

}

//读取文件流

FileInputStream fileInputStream = new FileInputStream(file);

//下载文件

//设置响应头和下载保存的文件名

if(filename != null && filename.length() >0){

// response.setContentType("application/x-msdownload");

response.setContentType("application/zip");

response.addHeader("Content-Disposition", "attachment; filename=" + new String(filename.getBytes("gb2312"),"iso8859-1") + "");

response.addHeader("Content-Length", "" + file.length());

if(null != fileInputStream){

int filelen = fileInputStream.available();//filelen/1000k

//文件太大时内存不能一次读出，要循环

byte a[] = new byte[filelen];

fileInputStream.read(a);

out.write(a);

}

fileInputStream.close();

out.close();

}

 

 

如果用servlet 统计并跳转到资源地址 可以使用cdn设置好的宽带。减少机房压力。

 

response.sendRedirect(filePath);