struts2导出Excel poi

package fhhb.action; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.List; import javax.servlet.http.HttpServletResponse; import org.apache.poi.hssf.usermodel.HSSFDataFormat; import org.apache.poi.hssf.usermodel.HSSFWorkbook; import org.apache.poi.ss.usermodel.CellStyle; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.ss.usermodel.Sheet; import org.apache.poi.ss.usermodel.Workbook; import com.opensymphony.xwork2.ActionSupport; import fhhb.bean.Student; import fhhb.service.StudentService; import fhhb.service.StudentServiceImpl; public class ExpotAction extends ActionSupport { private InputStream excelFile; // ++++++++++++++++++++++++++ /* * 数据库只有3列分别是id,name,sex * 查询后绑定到对象后 将对象赋值给list * 然后转成对象进行列操作 * */ public void ExcelFile() { Workbook workbook = null; StudentService studentService = new StudentServiceImpl(); workbook = new HSSFWorkbook(); Sheet sheet = workbook.createSheet("学生信息"); Row row = sheet.createRow(0); row.createCell(0).setCellValue("学号"); row.createCell(1).setCellValue("姓名"); row.createCell(2).setCellValue("性别"); CellStyle cellStyle = workbook.createCellStyle(); cellStyle.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy")); List<Student> list = studentService.findAll(); for (int i = 1; i <= list.size(); i++) { Student stu = list.get(i - 1); row = sheet.createRow(i); row.createCell(0).setCellValue(stu.getId()); row.createCell(1).setCellValue(stu.getName()); row.createCell(2).setCellValue(stu.getSex()); } ByteArrayOutputStream baos = new ByteArrayOutputStream(); try { workbook.write(baos); } catch (IOException e) { e.printStackTrace(); } byte[] aa = baos.toByteArray(); excelFile = new ByteArrayInputStream(aa,0,aa.length); try { baos.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public String execute() throws Exception { //getExcelFile(); //super.execute(); ExcelFile(); return "suc"; } public InputStream getExcelFile() { return excelFile; } }