response.setCharacterEncoding("UTF-8");
//编码格式为UTF-8
response.setContentType("application/vnd.ms-excel;charset=UTF-8");
//让服务器告诉浏览器它发送的数据属于excel文件类型
其他常用类型：
'doc' => 'application/msword',
'bin' => 'application/octet-stream',
'exe' => 'application/octet-stream',
'so' => 'application/octet-stream',
'dll' => 'application/octet-stream',
'pdf' => 'application/pdf',
'ai' => 'application/postscript',
'xls' => 'application/vnd.ms-excel',
'ppt' => 'application/vnd.ms-powerpoint',
'dir' => 'application/x-director',
'js' => 'application/x-javascript',
'swf' => 'application/x-shockwave-flash',
'xhtml' => 'application/xhtml+xml',
'xht' => 'application/xhtml+xml',
'zip' => 'application/zip',
'mid' => 'audio/midi',
'midi' => 'audio/midi',
'mp3' => 'audio/mpeg',
'rm' => 'audio/x-pn-realaudio',
'rpm' => 'audio/x-pn-realaudio-plugin',
'wav' => 'audio/x-wav',
'bmp' => 'image/bmp',
'gif' => 'image/gif',
'jpeg' => 'image/jpeg',
'jpg' => 'image/jpeg',
'png' => 'image/png',
'css' => 'text/css',
'html' => 'text/html',
'htm' => 'text/html',
'txt' => 'text/plain',
'xsl' => 'text/xml',
'xml' => 'text/xml',
'mpeg' => 'video/mpeg',
'mpg' => 'video/mpeg',
'avi' => 'video/x-msvideo',
'movie' => 'video/x-sgi-movie',
response.setHeader("Content-Transfer-Encoding", "binary");
//描述内容在传输过程中的编码格式，BINARY可能不止包含非ASCII字符，还可能不是一个短行（超过1000字符）。
response.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
//must-revalidate：强制页面不缓存，post-check=0, pre-check=0：0秒后，在显示给用户之前，该对象被选中进行更新过
response.setHeader("Pragma", "public");
//表示响应可能是任何缓存的，即使它只是通常是非缓存或可缓存的仅在非共享缓存中。
response.setHeader("Content-Disposition", "attachment;filename="" + fileName + ".xls"");
//告诉浏览器这个文件的名字和类型，attachment：作为附件下载；inline：直接打开