使用POI进行Excel文件下载的示例工程

说明：
1.下载http://www.apache.org/dyn/closer.cgi/poi/release/bin/poi-bin-3.7-20101029.zip后，将poi-3.7目录下的jar包放入lib目录， 再将此工程载入Eclipse/MyEclipse即可。
2.界面中文本框供输出数据量用，在我的T410上测试数据量在3.5W~3.6W之间，再多就报java.lang.OutOfMemoryError错误。
3.主要代码如下：

Sevlet代码：

<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--> package  com.heyang.action;


import  java.io.BufferedOutputStream;

import  javax.servlet.ServletException;
import  javax.servlet.ServletOutputStream;
import  javax.servlet.http.HttpServlet;
import  javax.servlet.http.HttpServletRequest;
import  javax.servlet.http.HttpServletResponse;

import  org.apache.poi.hssf.usermodel.HSSFWorkbook;

import  com.heyang.service.DownloadService;

/**
 * POI下载的Servlet
 *  @author  heyang
 *
  */
public   class  DownloadServlet  extends  HttpServlet {
     private   static   final   long  serialVersionUID  =   56890894234786L ;
    
     public   void  doPost(HttpServletRequest request, HttpServletResponse response)
             throws  ServletException, java.io.IOException {
        String fileName = " download.xls " ;
        response.setHeader( " Content-disposition " ,  " attachment; filename= " + fileName); //  设定输出文件头   
        response.setContentType( " application/msexcel " ); //  定义输出类型 
        
         try {
             int  rowCount = Integer.parseInt(request.getParameter( " rowCount " ));
            
             //  表头行
            String[] headers = new  String[]{ " 更新ID " , " 账期 " , " 基站编号 " , " 基站名称 " , " 站点状态 " , " 部门名称 " , " 站点类型 " , " 占用类型 " , " 预提(元) " , " 未核销金额 " , " 上期未核销 " , " 开始月份 " , " 结束月份 " , " 上期抄表数 " , " 本期抄表数 " , " 电价 " , " 电量 " , " 本期报账(元) " , " 补提(元) " , " 预提汇总(元) " , " 成本中心 " , " 专业 " , " 本期报账单号 " , " 基站类别 " , " 线损 " };
            DownloadService service = new  DownloadService();

            HSSFWorkbook workbook = service.generateWorkbook(rowCount, headers.length);

            ServletOutputStream out  =  response.getOutputStream();
            BufferedOutputStream bos  =   new  BufferedOutputStream(out);        
            workbook.write(bos);
            bos.flush();
            bos.close();
            
        } catch (Exception ex){
            ex.printStackTrace();
        }
        
         return  ;
    }
        
     public   void  doGet(HttpServletRequest request, HttpServletResponse response)
             throws  ServletException, java.io.IOException {
        doPost(request, response);
    }
}

Service代码：

<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--> package  com.heyang.service;

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;


/**
 * 下载服务类
 * 
 *  @author  heyang
 *
  */
public   class  DownloadService{
     /**
     * 生成工作簿对象
     *  @param  rowCount
     *  @param  columnCount
     *  @return
      */
     public  HSSFWorkbook generateWorkbook( int  rowCount, int  columnCount)  throws  Exception{
        HSSFWorkbook workbook  =   new  HSSFWorkbook();  // 产生工作簿对象
        HSSFSheet sheet  =  workbook.createSheet();  // 产生工作表对象
        String value = null ;
        
        HSSFRow row  =   null ;
        HSSFCell cell  =   null ;
        
         for ( int  i = 0 ;i < rowCount;i ++ ){
            row  =  sheet.createRow(i); // 创建一行
            
             for ( int  j = 0 ;j < columnCount;j ++ ){
                value = "" + i + " , " + j;
                
                cell  =  row.createCell(j);
                cell.setCellValue(value);
                
                cell  =   null ;
            }
            
            row  =   null ;
        }
        
        row  =   null ;
        cell  =   null ;
        
         return  workbook;
    }
}