我正在尝试下载一个excel文件。
在我的动作课上

public class ActivityTrackerExlReportAction extends BaseAction 
{
private  InputStream excelStream;
private UserMasterDTO userMasterDTO;

public InputStream getExcelStream() 
{
 return excelStream;
}

public void setExcelStream(InputStream excelStream) {
this.excelStream = excelStream;
}

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
WorkbookSettings wbSettings = new WorkbookSettings();

try
{
  response.setHeader("Content-Disposition", "attachment; filename=/timesheet.xls");
  wbSettings.setLocale(new Locale("en", "EN"));
  WritableWorkbook workbook = Workbook.createWorkbook(outputStream, wbSettings);
  workbook.createSheet("Report", 0);
  WritableSheet excelSheet = workbook.getSheet(0);
  service.createLabel(excelSheet);
  service.createContent(excelSheet);  

  workbook.write();

  ByteArrayInputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());

  setExcelStream(inputStream);

  workbook.close();

  outStream.flush();

  outStream.close();
}
catch(Exception e)
{
}
finally
{
// outStream.close();
 }
 return "generateReport
}

我的struts.xml包含：

<result type="stream" name="generateReport">
 <param name="contentType">"application/vnd.ms-excel"</param>
 <param name="inputName">excelStream</param>
 <param name="bufferSize">1024</param>
</result>

我正在使用JXL创建和编写Excel工作表。为什么我会得到错误，如何摆脱它？在调用堆栈中找不到名为[excelStream]的java.io.InputStream
我是Stacktrace：
java.lang.IllegalArgumentException：在调用堆栈中找不到名为[excelStream]的java.io.InputStream。检查为此操作指定的标记。
org.apache.struts2.dispatcher.StreamResult.doExecute（StreamResult.java：237）
org.apache.struts2.dispatcher.StrutsResultSupport.execute（StrutsResultSupport.java：186）.......