如果它是一个简单的文件，只是放在公共web内容（在那里你放置你的静态和JSF文件），并创建一个链接。

If it's a simple file, just place in public webcontent (there where you put your static and JSF files) and create a link.

<h:outputLink value="/files/file.ext">link</h:outputLink>

servletcontainer将担心应用正确的标题。

The servletcontainer will worry about applying the correct headers.

如果由于某些特定原因（例如在服务器机器或数据库中的固定路径），它位于公共Web内容之外，则创建一个获取 InputStream ，并将其写入 OutputStream $ c至少$ code> Content-Type ， Content-Disposition 和 Content-Length 标题。您可以在此这里找到一个简单的开球示例。还可以在servlet的 url-pattern 上简单地链接。

If it's located outside the public webcontent for some specific reasons (e.g. in a fixed path at server machine, or in a database), then create a servlet which gets an InputStream of it and writes it to the OutputStream of the response along at least the Content-Type, Content-Disposition and Content-Length headers. You can find here a simple kickoff example. Also that can simply be linked on the servlet's url-pattern.

如果要动态生成，并且取决于JSF具体的请求参数，那么你也可以在受到管理的bean操作中执行，该操作由 h：commandLink 或 h：commandButton ，但您只需要确保您调用 FacesContext＃responseComplete（） 在bean的动作方法的结尾，以防止JSF在手中进行导航。可以重复使用相同类型的servlet代码来流式传输文件。您可以在这个答案。

If it's to be dynamically generated and depending on the JSF specific request parameters, then you can also do so in a managed bean action which is bound by h:commandLink or h:commandButton, but you only need to ensure that you call FacesContext#responseComplete() at end of bean's action method to prevent JSF from taking the navigation in hands. The same kind of servlet code can be reused to stream the file. You can find a kickoff example in this answer.