Disposition 处置；性情；部署；倾向

Content-disposition 是 MIME 协议的扩展，指示 MIME 用户代理如何显示附加的文件。

设置文件在浏览器打开还是下载

Content-Disposition属性有两种类型：inline 和 attachment 

inline 文件内容直接显示在页面 
attachment 下载

浏览器页面直接打开

response.setHeader("Content-Type","text/plain");  
response.addHeader("Content-Disposition","inline;filename=abc.txt");  
response.addHeader("Content-Length",file.length() + "");

下载 

response.setHeader("Content-Type","text/plain");  
response.addHeader("Content-Disposition","attachment;filename=xyz.txt");  
response.addHeader("Content-Length",file.length() + "" );


 
Content-Disposition=attachment; filename=xxx.csv
Content-Length=9999
Content-Type=application/octet-stream

application/octet-stream 
以流的形式下载文件,可实现任意格式的文件下载