从JSF应用程序的任何Web浏览器中强制进行另存为对话框

Question

我已经创建了一个JSF应用程序，我想在页面中嵌入一个链接，单击该链接会导致支持bean编排一些xml，并强制打开“另存为下载”对话框，以便用户可以选择要保存的位置。保存文件。我已经编写了JAXB代码。

怎么做？

谢谢

Answer 1

将HTTP Content-Disposition标头设置为attachment。这将弹出一个 另存为
对话框。您可以使用进行操作HttpServletResponse#setHeader()。您可以通过JSF幕后获得HTTP
servlet响应ExternalContext#getResponse()。

在JSF上下文中，只需要确保FacesContext#responseComplete()稍后再调用即可避免IllegalStateExceptions飞散。

开球示例：

public void download() throws IOException {
    FacesContext facesContext = FacesContext.getCurrentInstance();
    ExternalContext externalContext = facesContext.getExternalContext();
    HttpServletResponse response = (HttpServletResponse) externalContext.getResponse();

    response.reset(); // Some JSF component library or some Filter might have set some headers in the buffer beforehand. We want to get rid of them, else it may collide.
    response.setContentType("application/xml"); // Check http://www.iana.org/assignments/media-types for all types. Use if necessary ServletContext#getMimeType() for auto-detection based on filename.
    response.setHeader("Content-disposition", "attachment; filename=\"name.xml\""); // The Save As popup magic is done here. You can give it any filename you want, this only won't work in MSIE, it will use current request URL as filename instead.

    BufferedInputStream input = null;
    BufferedOutputStream output = null;

    try {
        input = new BufferedInputStream(getYourXmlAsInputStream());
        output = new BufferedOutputStream(response.getOutputStream());

        byte[] buffer = new byte[10240];
        for (int length; (length = input.read(buffer)) > 0;) {
            output.write(buffer, 0, length);
        }
    } finally {
        close(output);
        close(input);
    }

    facesContext.responseComplete(); // Important! Else JSF will attempt to render the response which obviously will fail since it's already written with a file and closed.
}