jsp中生成txt文件

import jxl.Workbook;
import jxl.write.Label;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;  

public class TxtDownLoad extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {  

        // 生成txt
        try {
            Date d = new Date();
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_kkmmss ");
            String random = sdf.format(d);
            String targetFile = random + ".csv";
            response.setContentType("application/x-msdownload");
            response.addHeader("Content-Disposition",
                    "attachment;   filename=\"" + targetFile + "\"");
            OutputStream os = response.getOutputStream();
            String temp = "你好啊！";
            os.write(temp.getBytes());
            os.close();
            response.flushBuffer();  

        } catch (Exception e) {
            System.out.println("生成txt文件时出错：");
            e.printStackTrace();
        }  

    }
}