使用JSF下载CSV文件 [英] Downloading a CSV file using JSF

问题描述

我不知道如何下载CSV文件。 CSV将在运行时生成。首先需要将文件保存在tomcat WEB-INF目录中吗？我正在使用JSF 1.2。

I don't know how to download a CSV file. The CSV will be generated at runtime. Do I need to save the file in the tomcat WEB-INF directory first? I'm using JSF 1.2.

顺便说一下，这种任务的最受欢迎的JSF组件是什么？

By the way, what's the favored JSF component for this kind of task?

编辑（05.05.2012 - 15:53）

Edit (05.05.2012 - 15:53)

我尝试了解决方案 BalusC 在他的第一个链接，但如果我点击我的命令按钮，该文件的内容将显示在网页上。可能是 mimetype 有问题？

I tried the solution BalusC stated in his first link, but if I click on my commandButton the content of the file is displayed on the webpage. Maybe there's a problem with the mimetype?

xhtml文件：

<a4j:form>
    <a4j:commandButton action="#{surveyEvaluationBean.doDataExport}" value="#{msg.srvExportButton}" />
</a4j:form>

main bean：

main bean:

    public String doDataExport() {

    try {
        export.downloadFile();  
    } catch (SurveyException e) {
        hasErrors = true;
    }
    return "";
}

export-bean：

export-bean:

public void downloadFile() throws SurveyException {

    try {

        String filename = "analysis.csv";

        FacesContext fc = FacesContext.getCurrentInstance();
        HttpServletResponse response = (HttpServletResponse) fc.getExternalContext().getResponse();

        response.reset();
        response.setContentType("text/comma-separated-values");
        response.setHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");

        OutputStream output = response.getOutputStream();

        // writing just sample data
        List<String> strings = new ArrayList<String>();

        strings.add("filename" + ";" + "description" + "\n");
        strings.add(filename + ";" + "this is just a test" + "\n");

        for (String s : strings) {
            output.write(s.getBytes());
        }

        output.flush();
        output.close();

        fc.responseComplete();

    } catch (IOException e) {
        throw new SurveyException("an error occurred");
    }
}

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编辑（05.05.2012 - 16:27）

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Edit (05.05.2012 - 16:27)

我解决了我的问题。我必须使用< h：commandButton> 而不是< a4j：commandButton> ，现在它可以工作！ / p>

I solved my problem. I have to use <h:commandButton> instead of <a4j:commandButton> and now it works!

推荐答案

我需要先将文件保存在tomcat WEB-INF目录中吗？

不，只要直接写入HTTP响应正文，就可以通过 ExternalContext＃ getResponseOutputStream（）在设置了正确的响应头后，告知浏览器将要检索的内容。

No, just write it straight to the HTTP response body as you obtain by ExternalContext#getResponseOutputStream() after having set the proper response headers which tells the browser what it's going to retrieve.

根据具体示例进行数学在以下答案中找到：

Do the math based on the concrete examples found in the following answers:

• 如何从JSF备份bean提供文件下载


• < a href =https://stackoverflow.com/questions/477886/jsp-generating-excel-spreadsheet-xls-to-download/2154226#2154226> JSP生成Excel电子表格（XL S）下载

• How to provide a file download from a JSF backing bean?
• JSP generating Excel spreadsheet (XLS) to download

基本上：

List<List<Object>> csv = createItSomehow();
writeCsv(csv, ';', ec.getResponseOutputStream());

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顺便说一下，这种任务最喜欢的jsf组件是什么？

这是主观的。但无论如何，我们正在使用 < p：dataExporter> 完全满意。

This is subjective. But anyway, we're using <p:dataExporter> to full satisfaction.

这篇关于使用JSF下载CSV文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！