java将List中的数据导入到excel表中

/*package com.dqd.shop.user.action;import java.util.List;import com.dqd.shop.user.vo.User;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class GetDataAction extends ActionSupport{	public String getData(){		List<User> list =(List<User>) ActionContext.getContext().getsession().get("data");		for(User u:list){			System.out.PRintln(u+"---");		}		return NONE;	}}*/package com.dqd.shop.user.action;import java.io.File;import java.io.IOException;import java.util.ArrayList;import java.util.List;import jxl.Cell;import jxl.Sheet;import jxl.Workbook;import jxl.write.Label;import jxl.write.Number;import jxl.write.WritableImage;import jxl.write.WritableSheet;import jxl.write.WritableWorkbook;import jxl.write.WriteException;import org.apache.commons.lang3.math.NumberUtils;import com.dqd.shop.user.vo.User;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;/** * Excel导入导出 *  * @author dqd * @version 1.0 Feb 7, 2014 4:14:51 PM */public class GetDataAction extends ActionSupport{    /**     * 导出(导出到磁盘)     */      public void exportExcel() {        WritableWorkbook book = null;        try {            // 打开文件            book = Workbook.createWorkbook(new File("D:/test/测试.xls"));            // 生成名为"学生"的工作表，参数0表示这是第一页            WritableSheet sheet = book.createSheet("学生", 0);            // 指定单元格位置是第一列第一行(0, 0)以及单元格内容为张三            Label label = new Label(0, 0, "张三");            // 将定义好的单元格添加到工作表中            sheet.addCell(label);            // 保存数字的单元格必须使用Number的完整包路径            jxl.write.Number number = new jxl.write.Number(1, 0, 30);            sheet.addCell(number);            // 写入数据并关闭文件            book.write();        } catch (Exception e) {            System.out.println(e);        }finally{            if(book!=null){                try {                    book.close();                } catch (Exception e) {                    e.printStackTrace();                }             }        }    }        /**     * 对象数据写入到Excel     */        public String  getData() {        WritableWorkbook book = null;        try {            // 打开文件            book = Workbook.createWorkbook(new File("D:/text/stu.xls"));            // 生成名为"学生"的工作表，参数0表示这是第一页            WritableSheet sheet = book.createSheet("证券数据", 0);                        List<User> list =(List<User>) ActionContext.getContext().getSession().get("data");            if(list!=null && !list.isEmpty()){                for(int i=0; i<list.size(); i++){                   // sheet.addCell(new Label(0, i, String.valueOf(list.get(i).getUid())));                    sheet.addCell(new Number(0, i, list.get(i).getUnumber()));                    sheet.addCell(new Label(1, i, String.valueOf(list.get(i).getUtime())));                    sheet.addCell(new Label(2, i, String.valueOf(list.get(i).getUcount())));                }            }                        // 写入数据并关闭文件            book.write();        } catch (Exception e) {            System.out.println(e);        }finally{            if(book!=null){                try {                    book.close();                } catch (Exception e) {                    e.printStackTrace();                }             }        }		return NONE;        }   }