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;
????}
}