Struts 2 - HTTP 状态 500 - 找不到名称为 java.io.InputStream

Question

这与以下问题类似：

Question A

Question B

但我无法在我的情况下应用解决方案。也许有人可以在我的代码中发现错误。

我想在我的 Struts2 应用程序中生成 Excel 文件并让用户下载它，但出现错误：

“HTTP 状态 500 - 找不到具有该名称的 java.io.InputStream”

通过调试器，我已经确认创建了带有文件内容的正确输入流，并且方法返回“成功”，因此 Struts 似乎没有拾取此流。

在struts.xml 我有：

    <action name="exportReferences" class="manageRefAction" method="exportReferences">
        <result name="success" type="stream">
            <param name="contentType">application/vnd.ms-excel;charset=utf-8</param>
            <param name="contentDisposition">contentDisposition</param>
            <param name="inputName">excelStream</param>
            <param name="bufferSize">1024</param>
        </result>
            (...)
    </action>   

然后在ManageRefAction 班级我有：

private InputStream excelStream;

  public InputStream getExcelStream() {
        return this.excelStream;
    }

 public String exportReferences() {

        List<ReferenceData> referenceXLSList = null;
        String exportFilename = null;
        String filename = "";
        String retrunStr = process();

        Map session = (Map) ActionContext.getContext().get("session");

        if (retrunStr.equalsIgnoreCase(ActionSupport.LOGIN)) {
            setLog("2");

            return LOGIN;
        } else {
            //Export only data with user's locale
            ArrayList userLocale = (ArrayList) session.get("userLocale");
            List<ArrayList> list = Arrays.asList(userLocale);
            try {
                referenceXLSList = referenceDataService.fetchReferenceDataXls();
                // Data filtering
                for (Iterator<ReferenceData> iterator = referenceXLSList.iterator(); iterator.hasNext(); ) {
                    ReferenceData ref = iterator.next();
                    String l = ref.getLocal().toLowerCase();
                    if (!userLocale.contains(l)) {
                        iterator.remove();
                    }
                }
                if (referenceXLSList.isEmpty()) {
                    return INPUT;
                }
                ServletContext servletContext = ServletActionContext.getServletContext();
                String exportFolderPath = servletContext.getRealPath("/files" + "/xls");

                File folder = new File(exportFolderPath);
                // Creation of the folder if it is not existing
                if (!folder.exists())
                    folder.mkdirs();

                exportFilename = PLConstants.REF_SHEET_NAME + PLConstants.XLS_FILE_EXTENSION;
                filename = exportFolderPath + "/" + exportFilename;
                File file = new File(filename);
                file.createNewFile();
                ExcelWriter writer = new ExcelWriter();
                Workbook wb = writer.writeRefData(filename, exportFilename, referenceXLSList);
                setContentDisposition("attachment; filename=" + exportFilename);
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                wb.write(baos);
                this.excelStream = new ByteArrayInputStream(baos.toByteArray());
                return SUCCESS;
            } catch (Throwable e) {
                e.printStackTrace();
                logger.info("Exception while exporting partner references", e);
                return INPUT;
            }
        }

    }

Answer 1

试试这个，contentDisposition 是字符串值没有进入 struts.xml。 所以，它抛出了一个异常。在参数中使用这个语法${contentDisposition}

    <action name="exportReferences" class="manageRefAction" method="exportReferences">
    <result name="success" type="stream">
        <param name="contentType">application/vnd.ms-excel;charset=utf-8</param>
        <param name="contentDisposition">${contentDisposition}</param>
        <param name="inputName">excelStream</param>
        <param name="bufferSize">1024</param>
    </result>
        (...)
  </action>