最近在时使POI导出excel表格的时候，遇到了ServletOutputStream和PrintWriter冲突问题，我的代码是这样写的:
/*
 * Generated by MyEclipse Struts
 * Template path: templates/java/JavaClass.vtl
 */
package BlueToothSystem.action;

import java.io.FileOutputStream;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class DownLoadAction extends Action {
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) {
        try{
            response.reset();
            response.setContentType("application/vnd.ms-excel;charset=utf-8");
            response.addHeader("Content-Disposition", "attachment;Filename=Report.xls");
            response.setCharacterEncoding("utf-8");
            
            ServletOutputStream so = response.getOutputStream();
            HSSFWorkbook hwb = new HSSFWorkbook();    //create the excel work book
            HSSFSheet sheet = hwb.createSheet();    //create the excel table
            HSSFRow row = sheet.createRow(0);
            HSSFCell cell = row.createCell(0);
            cell.setCellType(HSSFCell.CELL_TYPE_STRING);
            cell.setCellValue("ProductName");
            hwb.write(so);
            so.flush();
            so.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }
}
不知道如何处理？还请各位大哥，帮帮忙！非常感谢!