导入包这一些不多说，直接贴出关键代码，JSP只要点一个Action链接就行。
poi包我是用：poi-3.11-20141221.jar
亲测有效：
效果：
Action 类代码：
private InputStream inputStream; //（get,set方法省略）定义一个输入流，用于接住在Service类生成的含有EXCEL的输入流
public String exportNetworkDeviceList() throws Exception {
setInputStream(networkDeviceService.exportNetworkDeviceList(NET_STATUS, NET_MODEL_NUMBER, NET_BUILDING, NET_FLOOR, NET_LOCATION));
return "getNetworkDeviceExportList";
}
Service类代码：（生成EXCEL表格代码在Service类写）
public InputStream exportNetworkDeviceList(String netStatus,
String netModelNumber, String netBuilding, String netFloor,
String netLocation) {
HSSFWorkbook wb = new HSSFWorkbook();
// 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet
HSSFSheet sheet = wb.createSheet("表一");
// 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制short
HSSFRow row = sheet.createRow((int) 0);
// 第四步，创建单元格，并设置值表头 设置表头居中
HSSFCellStyle style = wb.createCellStyle();
style.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 创建一个居中格式
//写列名，视自己的需求而定
HSSFCell cell = row.createCell(0);
cell.setCellValue("设备型号");
cell.setCellStyle(style);
cell = row.createCell(1);
cell.setCellValue("端口数");
cell.setCellStyle(style);
cell = row.createCell(2);
cell.setCellValue("设备名称");
cell.setCellStyle(style);
cell = row.createCell(3);
cell.setCellValue("状态");
cell.setCellStyle(style);
cell = row.createCell(4);
cell.setCellValue("楼宇");
cell.setCellStyle(style);
cell = row.createCell(5);
cell.setCellValue("楼层");
cell.setCellStyle(style);
cell = row.createCell(6);
cell.setCellValue("位置");
cell.setCellStyle(style);
cell = row.createCell(7);
cell.setCellValue("接口");
cell.setCellStyle(style);
cell = row.createCell(8);
cell.setCellValue("IP地址");
cell.setCellStyle(style);
cell = row.createCell(9);
cell.setCellValue("网关");
cell.setCellStyle(style);
cell = row.createCell(10);
cell.setCellValue("备注");
cell.setCellStyle(style);
//构造数据库查询语句，待会我用与从DAO类取数据，视自己的需求而定，个人建议将这一部分写在另一个方法里面
String hql = "from NetworkDevice ";
if (netStatus == null) {
} else {
if (netStatus.equalsIgnoreCase("00")) {
hql += "n where n.NET_STATUS!=null ";
} else {
hql += "n where n.NET_STATUS='" + netStatus + "' ";
}
;
if (!netModelNumber.isEmpty()) {
hql += "AND n.NET_MODEL_NUMBER = '" + netModelNumber + "' ";
}
;
if (!netBuilding.isEmpty()) {
hql += "AND n.NET_BUILDING = '" + netBuilding + "' ";
}
;
if (!netFloor.isEmpty()) {
hql += "AND n.NET_FLOOR = '" + netFloor + "' ";
}
;
if (!netLocation.isEmpty()) {
hql += "AND n.NET_LOCATION = '" + netLocation + "' ";
}
;
}
hql += "order by 1 DESC";
// 第五步，写入实体数据 实际应用中这些数据从数据库得到，
List<NetworkDevice> exportList = networkDeviceDaoImpl.exportNetworkDeviceList(hql);
for (int i = 0; i < exportList.size(); i++) {
row = sheet.createRow((int) i + 1);
NetworkDevice netDevice = exportList.get(i);
// 第四步，创建单元格，并设置值
row.createCell(0).setCellValue(netDevice.getNET_MODEL_NUMBER());
row.createCell(1).setCellValue(netDevice.getNET_DEVICE_PORT());
row.createCell(2).setCellValue(netDevice.getNET_DEVICE_NAME());
row.createCell(3).setCellValue(netDevice.getNET_STATUS());
row.createCell(4).setCellValue(netDevice.getNET_BUILDING());
row.createCell(5).setCellValue(netDevice.getNET_FLOOR());
row.createCell(6).setCellValue(netDevice.getNET_LOCATION());
row.createCell(7).setCellValue(netDevice.getNET_INTERFACE());
row.createCell(8).setCellValue(netDevice.getNET_IP());
row.createCell(9).setCellValue(netDevice.getNET_GATEWAY());
row.createCell(10).setCellValue(netDevice.getNET_REMARK());
}
//自动设置EXCEL的列宽，视自己的需求而定，也可以用sheet.setDefaultColumnWidth(13);为全部列的列宽设置默认值
sheet.autoSizeColumn((short)0);
sheet.autoSizeColumn((short)2);
sheet.autoSizeColumn((short)6);
sheet.autoSizeColumn((short)7);
sheet.autoSizeColumn((short)8);
sheet.autoSizeColumn((short)9);
sheet.autoSizeColumn((short)10);
//设置文件名，用格式化日期来生成一个ID
String filePath="";
Date dt = new Date();
DateFormat df = new SimpleDateFormat("yyyyMMddHHmmss");
String date = df.format(dt).toString();
filePath = "NetDevice" + date + ".xls";
File file=new File(filePath);
try{
OutputStream out=new FileOutputStream(file);
wb.write(out);
out.close();
}catch(Exception e){
e.printStackTrace();
}
InputStream in=null;
try{
in=new FileInputStream(file);
}catch(Exception e)
{
e.printStackTrace();
}
return in;
}
strust2代码：
<action name="ExportNetworkDeviceList" class="com.javaweb.action.NetworkDeviceAction"
method="exportNetworkDeviceList">
<result name="getNetworkDeviceExportList" type="stream">
<param name="inputStream">excelStream</param>
<param name="ContentType">application/vnd.ms-excel</param>
<param name="contentDisposition">filename="NetDevice.xls"</param>
</result>
</action>
PS：据网友@puyans反馈，若strust2的代码写：<param name="inputStream">excelStream</param> 控制台会报：
Cannot create type class java.io.InputStream from value excelStream - [unknown location]
若出现这种情况，请改为：
<param name="inputStream">inputStream</param>