导出Excel通用工具类

导出Excel的两种方法：

一，POI

导入poi包

poi-3.11-beta3-20141111.jar

 1 /**

 2 * 

 3 */

 4 package com.car.ots.mpckp.utils;

 5 

 6 import java.io.OutputStream;

 7 import java.net.URLEncoder;

 8 import java.util.List;

 9 

10 import javax.servlet.http.HttpServletRequest;

11 import javax.servlet.http.HttpServletResponse;

12 

13 import org.apache.commons.beanutils.BeanUtils;

14 import org.apache.poi.hssf.usermodel.HSSFCell;

15 import org.apache.poi.hssf.usermodel.HSSFCellStyle;

16 import org.apache.poi.hssf.usermodel.HSSFRow;

17 import org.apache.poi.hssf.usermodel.HSSFSheet;

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

19 

20 /**

21 * @author cora.guo

22 * 

23 */

24 public class ExportUtils {

25 

26 public static void createExcel(HttpServletRequest req,

27 HttpServletResponse resp, List<Object> datas, String sheetName,

28 List<String> headers, List<String> colunmValueNames)

29 throws Exception {

30 OutputStream out = null;

31 try {

32 // 第一步，创建一个webbook，对应一个Excel文件

33 resp.setContentType("application/vnd.ms-excel");

34 resp.setCharacterEncoding("UTF-8");

35 if (req.getHeader("User-Agent").toLowerCase().indexOf("msie") != -1) {

36 resp.setHeader("Content-Disposition", "attachment;filename="

37 + URLEncoder.encode(sheetName, "utf-8") + ".xls");

38 } else {

39 resp.setHeader("Content-Disposition", "attachment;filename="

40 + new String(sheetName.getBytes("utf-8"), "ISO-8859-1")

41 + ".xls");

42 }

43 resp.setHeader("Cache-Control", "max-age=0");

44 HSSFWorkbook wb = new HSSFWorkbook();

45 

46 // 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet

47 HSSFSheet sheet = wb.createSheet(sheetName);

48 // 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

49 HSSFRow row = sheet.createRow(0);

50 // 第四步，创建单元格，并设置值表头 设置表头居中

51 HSSFCellStyle style = wb.createCellStyle();

52 // 创建居中样式

53 style.setAlignment(HSSFCellStyle.ALIGN_CENTER);

54 HSSFCell cell = null;

55 if (headers != null && headers.size() > 0) {

56 for (int i = 0; i < headers.size(); i++) {

57 cell = row.createCell(i);

58 cell.setCellValue(headers.get(i));

59 cell.setCellStyle(style);

60 }

61 }

62 // 第五步，写入实体数据 实际应用中这些数据从数据库得到，

63 if (datas != null && datas.size() != 0) {

64 for (int r = 0; r < datas.size(); r++) {

65 Object obj = datas.get(r);

66 row = sheet.createRow(r+1);

67 if (colunmValueNames != null

68 && colunmValueNames.size() != 0) {

69 for (int j = 0; j < colunmValueNames.size(); j++) {

70 String name = colunmValueNames.get(j);

71 String value = BeanUtils.getProperty(obj, name);

72 // 创建单元格,设置值

73 cell = row.createCell(j);

74 cell.setCellStyle(style);

75 cell.setCellValue(value);

76 }

77 }

78 }

79 }

80 out = resp.getOutputStream();

81 wb.write(out);

82 } catch (Exception e) {

83 // TODO Auto-generated catch block

84 throw new Exception(e);

85 } finally {

86 out.close();

87 }

88 }

89 }

View Code

 

二，JXl

导入包

 1 package com.car.ots.uis.utils;

 2 

 3 import java.net.URLEncoder;

 4 import java.util.List;

 5 

 6 import javax.servlet.http.HttpServletRequest;

 7 import javax.servlet.http.HttpServletResponse;

 8 

 9 import jxl.Workbook;

10 import jxl.format.Alignment;

11 import jxl.format.VerticalAlignment;

12 import jxl.write.Label;

13 import jxl.write.WritableCellFormat;

14 import jxl.write.WritableFont;

15 import jxl.write.WritableSheet;

16 import jxl.write.WritableWorkbook;

17 

18 import org.apache.commons.beanutils.BeanUtils;

19 

20 public class ExportUtil {

21   public static void export(HttpServletRequest req, HttpServletResponse resp, List<Object> datas,

22       String sheetName, List<String> headers, List<String> colunmValueNames) throws Exception {

23     // 写入excel

24     WritableWorkbook wb = null;

25     WritableSheet ws = null;

26     Label label = null;

27 

28     try {

29       resp.setContentType("application/vnd.ms-excel");

30       resp.setCharacterEncoding("UTF-8");

31       if (req.getHeader("User-Agent").toLowerCase().indexOf("msie") != -1) {

32         resp.setHeader("Content-Disposition",

33             "attachment;filename=" + URLEncoder.encode(sheetName, "utf-8") + ".xls");

34       } else {

35         resp.setHeader("Content-Disposition",

36             "attachment;filename=" + new String(sheetName.getBytes("utf-8"), "ISO-8859-1") + ".xls");

37       }

38       resp.setHeader("Cache-Control", "max-age=0");

39       wb = Workbook.createWorkbook(resp.getOutputStream());

40 

41       ws = wb.createSheet(sheetName, 0);

42 

43       WritableFont bold_font = new WritableFont(WritableFont.ARIAL, 10, WritableFont.BOLD);

44       WritableCellFormat f = new WritableCellFormat(bold_font);

45       f.setVerticalAlignment(VerticalAlignment.CENTRE);

46       f.setAlignment(Alignment.CENTRE);

47       if(headers!=null&headers.size()!=0){

48           for (int i = 0; i < headers.size(); i++) {

49               ws.setColumnView(i, 25);

50               label = new Label(i, 0, headers.get(i), f);

51               ws.addCell(label);

52           }

53       }

54 

55       WritableFont nobold_font = new WritableFont(WritableFont.ARIAL, 10, WritableFont.NO_BOLD);

56       f = new WritableCellFormat(nobold_font);

57       f.setVerticalAlignment(VerticalAlignment.CENTRE);

58       f.setAlignment(Alignment.CENTRE);

59       if(datas!=null&&datas.size()!=0){

60           for (int r = 0; r < datas.size(); r++) {

61               Object obj = datas.get(r);

62               if (colunmValueNames!=null&&colunmValueNames.size()!=0) {

63                   for (int j = 0; j < colunmValueNames.size(); j++) {

64                       String name = colunmValueNames.get(j);

65                       String value = BeanUtils.getProperty(obj, name);

66                       label = new Label(j, r + 1, value, f);

67                       ws.addCell(label);

68                   }

69             }

70           }

71       }

72       wb.write();

73     } catch (Exception e) {

74       throw new Exception(e);

75     } finally {

76       wb.write();

77       wb.close();

78 

79     }

80   }

81 

82 }

View Code

两者区别：

POI为apache公司的一个子项目,主要是提供一组操作windows文档的Java API
JavaExcel俗称jxl是一开放源码项目，通过它开发人员可以读取Excel文件的内容、创建新的Excel文件、更新已经存在的Excel文件。使用该API非Windows操作系统也可以通过纯Java应用来处理Excel数据表。因为是使用Java编写的，所以我们在Web应用中可以通过JSP、Servlet来调用API实现对Excel数据表的访问。

JVM虚拟机内存消耗的情况：

数据量3000条数据,每条60列.JVM虚拟机内存大小64M.
使用POI:运行到2800条左右就报内存溢出.
使用JXL:3000条全部出来,并且内存还有21M的空间.
可想而知,在对内存的消耗方面差距还是挺大的.
也许是由于JXL在对资源回收利用方面做的不错.

效率方面：

也是基于大数据量而言的,数据量小的话基本上差别不大,也不难被发觉.但是大的数据量,POI消耗的JVM内存远比JXL消耗的多.但相比提供的功能的话,JXL又相对弱了点.所以如果要实现的功能比较复杂的情况下可以考虑使用POI,但如果只想生成一些大数据量可以考虑使用JXL