Content-Disposition 属性是作为对下载文件的一个标识字段，在rfc2616 http://www.rfc-editor.org/rfc/rfc2616.pdf 章节19.5 Additional Features中

有介绍，具体介绍请看 http://www.rfc-editor.org/rfc/rfc1806.txt

字段介绍如下：

2. disposition := "Content-Disposition" ":"

3. disposition-type

4. *(";" disposition-parm)

5. disposition-type := "inline"

6. / "attachment"

7. / extension-token

8. ; values are not case-sensitive

9. disposition-parm := filename-parm / parameter

10. filename-parm := "filename" "=" value;

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

inline ：将文件内容直接显示在页面

1. File file = new File("rfc1806.txt");

2. String filename = file.getName();

3. response.setHeader("Content-Type","text/plain");

4. response.addHeader("Content-Disposition","inline;filename=" + new String(filename.getBytes(),"utf-8"));

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

attachment：弹出对话框让用户下载

1. File file = new File("rfc1806.txt");

2. String filename = file.getName();

3. response.setHeader("Content-Type","text/plain");

4. response.addHeader("Content-Disposition","attachment;filename=" + new String(filename.getBytes(),"utf-8"));

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