String root= ServletActionContext.getServletContext().getRealPath(File.separator).replace("\\", File.separator);

String fileName = "download.text";

File file = new File(root + fileName);

in = new FileInputStream(file);

// 设置响应正文的MIME类型

response.setContentType("Content-Disposition;charset=utf-8");

response.setHeader("Content-Disposition", "attachment;" + " filename=\""+ URLEncoder.encode(fileName, "UTF-8") + "\"");

// 把本地文件发送给客户端

out = response.getOutputStream();

int byteRead = 0;

byte[] buffer = new byte[512];

while ((byteRead = in.read(buffer)) != -1)

{

　　out.write(buffer, 0, byteRead);

}

in.close();

out.close();