spring MVC通用文件下载

写个通用类

通过response实现下载

这样写有个好处，那就是通用，其他不用spring MVC的也可以用 

/**
 * 
 * @param request
 * @param response
 * @param filePath 文件全路径 
 * @param contentType （mimeType）默认可传application/octet-stream
 * @param realName 下载时显示的文件名
 * @throws Exception
 */
public static void download(HttpServletRequest request, HttpServletResponse response, String filePath, String contentType, String realName) throws Exception {
	// request.setCharacterEncoding("UTF-8");
	// String ctxPath = request.getSession().getServletContext().getRealPath("/") + FileUtil.UPLOADDIR;
	if(filePath.indexOf("..")!=-1){
		throw new IOException("文件名不合规，含有相对定位符！");
	}
	long fileLength = new File(filePath).length();

	response.setContentType(contentType); // "application/octet-stream"
	response.setHeader("Content-disposition", "attachment; filename=" + new String(realName.getBytes("GBK"), "ISO-8859-1"));

	response.setHeader("Content-Length", String.valueOf(fileLength));

	BufferedInputStream bis = new BufferedInputStream(new FileInputStream(filePath));
	BufferedOutputStream bos = new BufferedOutputStream(response.getOutputStream());
	byte[] buff = new byte[2048];
	int bytesRead;
	while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
		bos.write(buff, 0, bytesRead);
	}
	bis.close();
	bos.close();
}