无法使用 JSF 下载 excel 文件 [重复]

Question

您好，我一直在尝试编写代码，以便我可以生成一个 excel 表，并在用户单击下载按钮时下载它....我已经成功生成了 excel 表，但我尝试下载相同的表但我没有成功。

我使用的方法是：

public void download() throws IOException {
    File file = new File("D:\\pdf\\carrierReport7.xls");

    FacesContext facesContext = FacesContext.getCurrentInstance();

    HttpServletResponse response = (HttpServletResponse) facesContext.getExternalContext().getResponse();

    response.setHeader("Content-Disposition", "attachment;filename=" + file.getName());
    response.setHeader("Content-Type", "application/vnd.ms-excel");

    OutputStream outputStream = response.getOutputStream();

    FileInputStream fileInputStream = new FileInputStream(file);

    byte[] bytesBuffer = new byte[2048];

    int bytesRead = 0;

    while ((bytesRead = fileInputStream.read(bytesBuffer)) > 0) {
        outputStream.write(bytesBuffer, 0, bytesRead);
    }

    outputStream.flush();

    fileInputStream.close();
    outputStream.close();

    facesContext.responseComplete();
}

jsf 命令：

Answer 1

不知道你有没有勾选这个，但是必须在commandButton中声明ajax="false"...

<p:commandButton ajax="false" 
                 ..........
</p:commandButton>

Answer 2

这就是我在 JSF 2 中做类似事情的方式，不确定您使用的是哪个版本。

public void downloadAttachment(Attachment attachment) throws IOException {
    FacesContext fc = FacesContext.getCurrentInstance();
    ExternalContext ec = fc.getExternalContext();

    ec.responseReset(); // 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.
    ec.setResponseContentType(ec.getMimeType(attachment.getFilename()));        
    ec.setResponseContentLength(attachment.getFilesizeBytes().intValue()); // Set it with the file size. This header is optional. It will work if it's omitted, but the download progress will be unknown.
    ec.setResponseHeader("Content-Disposition", "attachment; filename=\"" + attachment.getFilename() + "\""); // The Save As popup magic is done here. You can give it any file name you want, this only won't work in MSIE, it will use current request URL as file name instead.

    OutputStream output = ec.getResponseOutputStream();
    output.write(attachment.getFileData());

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

}