问Java每隔5秒轮询5次

EN

package abc.documentdownload;

import abc.util.Email;

import java.io.BufferedOutputStream;
import java.io.IOException;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;

import javax.servlet.*;
import javax.servlet.http.*;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class DownloadDocServlet extends HttpServlet {
    private static final Log log = LogFactory.getLog(DownloadDocServlet.class);
    private static final String CONTENT_TYPE = "text/html; charset=windows-1252";

    public void init(ServletConfig config) throws ServletException {
        super.init(config);
    }

    public void doGet(HttpServletRequest request,
                      HttpServletResponse response) throws ServletException,
                                                           IOException {
        doPost(request, response);
    }

    public void doPost(HttpServletRequest request,
                       HttpServletResponse response) throws ServletException,
                                                            IOException {
        response.setContentType(CONTENT_TYPE);
        DownloadDocDAO DownloadInstance = new DownloadDocDAO();
        String downloadType = request.getParameter("downloadType");
        String pNumber = request.getParameter("PNumber");
        BufferedOutputStream output = null;
        String strFileName = pNumber + ".pdf";
        if(downloadType != null && downloadType.equalsIgnoreCase("download")){
            try{
                byte[] content=DownloadInstance.getP(pNumber);                
                log.info("COnverting content into PDF in EmailServlet");
                System.out.println("COnverting content into PDF in EmailServlet");
                response.setContentType("application/pdf");
                response.setHeader("Content-Disposition","attachment; filename=\"" + strFileName + "\"");
                response.setHeader("Cache-Control","no-cache"); 
                response.setHeader("Cache-Control","no-store"); 
                response.setHeader("Pragma","no-cache");
                response.setDateHeader("Expires", 0);
                output = new BufferedOutputStream(response.getOutputStream());
                output.write(content);
                output.flush();                            
                output.close();                

            }
            catch (Exception ex) {
                ex.printStackTrace();
                log.error("Error in DownloadDocServlet ", ex);
                /* Using the below block to trigger the email whenever there is a error*/
                Writer result = new StringWriter();
                PrintWriter printWriter = new PrintWriter(result);
                ex.printStackTrace(printWriter);
                Email emailSend = new Email();                                  
                int strEmailConfirm = emailSend.sendEmail("Exception in DownloadDocServlet of documentdownload package for pno :"+pNumber,"<B>Please find Exception Details for the DownloadDocServlet of documentdownload package</b><br><br>"+result.toString());
                log.info("strEmailConfirm in DownloadDocServlet"+strEmailConfirm); // if value is 1 ,  mail will be trigger is successful 
            } 
        }        
    }


}