JAVA EXCEL API:是一开放源码项目,通过它Java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。因为它是使用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。
下载:
官方网站 http://www.andykhan.com/jexcelapi/ 下载最新版本(本人下的是jexcelapi_2_6_12.tar.gz,解压后将里面的jxl.jar复制到WEB-INF/lib目录下面即可)
Java Excel API的jar包可以通过以下URL获得:
http://sourceforge.net/projects/jexcelapi/files/jexcelapi/2.6.6/jexcelapi_2_6_6.zip/download
(包括所有版本):http://sourceforge.net/projects/jexcelapi/files/
直接下载地址(迅雷上新建任务即可):
http://nchc.dl.sourceforge.net/project/jexcelapi/jexcelapi/2.6.6/jexcelapi_2_6_6.zip
一、JSP生成简单的Excel文件
package beans.excel; import java.io.IOException; import java.io.OutputStream; import jxl.Workbook; import jxl.write.Label; import jxl.write.WritableSheet; import jxl.write.WritableWorkbook; import jxl.write.WriteException; public class SimpleExcelWrite { public void createExcel(OutputStream os) throws WriteException,IOException{ //创建工作薄 WritableWorkbook workbook = Workbook.createWorkbook(os); //创建新的一页 WritableSheet sheet = workbook.createSheet("First Sheet",0); //创建要显示的内容,创建一个单元格,第一个参数为列坐标,第二个参数为行坐标,第三个参数为内容 Label xuexiao = new Label(0,0,"学校"); sheet.addCell(xuexiao); Label zhuanye = new Label(1,0,"专业"); sheet.addCell(zhuanye); Label jingzhengli = new Label(2,0,"专业竞争力"); sheet.addCell(jingzhengli); Label qinghua = new Label(0,1,"清华大学"); sheet.addCell(qinghua); Label jisuanji = new Label(1,1,"计算机专业"); sheet.addCell(jisuanji); Label gao = new Label(2,1,"高"); sheet.addCell(gao); Label beida = new Label(0,2,"北京大学"); sheet.addCell(beida); Label falv = new Label(1,2,"法律专业"); sheet.addCell(falv); Label zhong = new Label(2,2,"中"); sheet.addCell(zhong); Label ligong = new Label(0,3,"北京理工大学"); sheet.addCell(ligong); Label hangkong = new Label(1,3,"航空专业"); sheet.addCell(hangkong); Label di = new Label(2,3,"低"); sheet.addCell(di); //把创建的内容写入到输出流中,并关闭输出流 workbook.write(); workbook.close(); os.close(); } }
SimpleExcelWrite.jsp
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%> <%@ page import="java.io.*" %> <%@ page import="beans.excel.*" %> <% String fname = "学校竞争力情况"; OutputStream os = response.getOutputStream();//取得输出流 response.reset();//清空输出流 //下面是对中文文件名的处理 response.setCharacterEncoding("UTF-8");//设置相应内容的编码格式 fname = java.net.URLEncoder.encode(fname,"UTF-8"); response.setHeader("Content-Disposition","attachment;filename="+new String(fname.getBytes("UTF-8"),"GBK")+".xls"); response.setContentType("application/msexcel");//定义输出类型 SimpleExcelWrite sw = new SimpleExcelWrite(); sw.createExcel(os); %> <html> <head> <title></title> </head> <body> </body> </html>
二、生成复杂数据格式Excel文件
package beans.excel; import java.io.IOException; import java.io.OutputStream; import java.util.Calendar; import java.util.Date; import jxl.Workbook; import jxl.write.Boolean; import jxl.write.DateFormats; import jxl.write.DateTime; import jxl.write.Label; import jxl.write.Number; import jxl.write.WritableCellFormat; import jxl.write.WritableSheet; import jxl.write.WritableWorkbook; import jxl.write.WriteException; public class ComplexDataExcelWrite { public void createExcel(OutputStream os) throws WriteException,IOException { //创建工作薄 WritableWorkbook workbook = Workbook.createWorkbook(os); //创建新的一页 WritableSheet sheet = workbook.createSheet("First Sheet", 0); //创建要显示的具体内容 Label formate = new Label(0,0,"数据格式"); sheet.addCell(formate); Label floats = new Label(1,0,"浮点型"); sheet.addCell(floats); Label integers = new Label(2,0,"整型"); sheet.addCell(integers); Label booleans = new Label(3,0,"布尔型"); sheet.addCell(booleans); Label dates = new Label(4,0,"日期格式"); sheet.addCell(dates); Label example = new Label(0,1,"数据示例"); sheet.addCell(example); //浮点数据 Number number = new Number(1,1,3.1415926535); sheet.addCell(number); //整形数据 Number ints = new Number(2,1,15042699); sheet.addCell(ints); Boolean bools = new Boolean(3,1,true); sheet.addCell(bools); //日期型数据 Calendar c = Calendar.getInstance(); Date date = c.getTime(); WritableCellFormat cf1 = new WritableCellFormat(DateFormats.FORMAT1); DateTime dt = new DateTime(4,1,date,cf1); sheet.addCell(dt); //把创建的内容写入到输出流中,并关闭输出流 workbook.write(); workbook.close(); os.close(); } }
三、生成复杂布局和样式的Excel文件
package beans.excel; import java.io.IOException; import java.io.OutputStream; import java.util.Calendar; import java.util.Date; import jxl.Workbook; import jxl.format.Colour; import jxl.format.UnderlineStyle; import jxl.write.Boolean; import jxl.write.DateFormats; import jxl.write.DateTime; import jxl.write.Label; import jxl.write.Number; import jxl.write.WritableCellFormat; import jxl.write.WritableFont; import jxl.write.WritableSheet; import jxl.write.WritableWorkbook; import jxl.write.WriteException; public class MutiStyleExcelWrite { public void createExcel(OutputStream os) throws WriteException,IOException { //创建工作薄 WritableWorkbook workbook = Workbook.createWorkbook(os); //创建新的一页 WritableSheet sheet = workbook.createSheet("First Sheet", 0); //构造表头 sheet.mergeCells(0, 0, 4, 0);//添加合并单元格,第一个参数是起始列,第二个参数是起始行,第三个参数是终止列,第四个参数是终止行 WritableFont bold = new WritableFont(WritableFont.ARIAL,10,WritableFont.BOLD);//设置字体种类和黑体显示,字体为Arial,字号大小为10,采用黑体显示 WritableCellFormat titleFormate = new WritableCellFormat(bold);//生成一个单元格样式控制对象 titleFormate.setAlignment(jxl.format.Alignment.CENTRE);//单元格中的内容水平方向居中 titleFormate.setVerticalAlignment(jxl.format.VerticalAlignment.CENTRE);//单元格的内容垂直方向居中 Label title = new Label(0,0,"JExcelApi支持数据类型详细说明",titleFormate); sheet.setRowView(0, 600, false);//设置第一行的高度 sheet.addCell(title); //创建要显示的具体内容 WritableFont color = new WritableFont(WritableFont.ARIAL);//选择字体 color.setColour(Colour.GOLD);//设置字体颜色为金黄色 WritableCellFormat colorFormat = new WritableCellFormat(color); Label formate = new Label(0,1,"数据格式",colorFormat); sheet.addCell(formate); Label floats = new Label(1,1,"浮点型"); sheet.addCell(floats); Label integers = new Label(2,1,"整型"); sheet.addCell(integers); Label booleans = new Label(3,1,"布尔型"); sheet.addCell(booleans); Label dates = new Label(4,1,"日期格式"); sheet.addCell(dates); Label example = new Label(0,2,"数据示例",colorFormat); sheet.addCell(example); //浮点数据 //设置下划线 WritableFont underline= new WritableFont(WritableFont.ARIAL,WritableFont.DEFAULT_POINT_SIZE,WritableFont.NO_BOLD,false,UnderlineStyle.SINGLE); WritableCellFormat greyBackground = new WritableCellFormat(underline); greyBackground.setBackground(Colour.GRAY_25);//设置背景颜色为灰色 Number number = new Number(1,2,3.1415926535,greyBackground); sheet.addCell(number); //整形数据 WritableFont boldNumber = new WritableFont(WritableFont.ARIAL,10,WritableFont.BOLD);//黑体 WritableCellFormat boldNumberFormate = new WritableCellFormat(boldNumber); Number ints = new Number(2,2,15042699,boldNumberFormate); sheet.addCell(ints); //布尔型数据 Boolean bools = new Boolean(3,2,true); sheet.addCell(bools); //日期型数据 //设置黑体和下划线 WritableFont boldDate = new WritableFont(WritableFont.ARIAL,WritableFont.DEFAULT_POINT_SIZE,WritableFont.BOLD,false,UnderlineStyle.SINGLE); WritableCellFormat boldDateFormate = new WritableCellFormat(boldDate,DateFormats.FORMAT1); Calendar c = Calendar.getInstance(); Date date = c.getTime(); DateTime dt = new DateTime(4,2,date,boldDateFormate); sheet.addCell(dt); //把创建的内容写入到输出流中,并关闭输出流 workbook.write(); workbook.close(); os.close(); } }
四、JSP读取Excel报表
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%> <%@ page import="java.io.File" %> <%@ page import="jxl.Cell" %> <%@ page import="jxl.Sheet" %> <%@ page import="jxl.Workbook" %> <html> <head> <title></title> </head> <body> <font size="2"> <% String fileName = "D:/学校竞争力情况.xls"; File file = new File(fileName);//根据文件名创建一个文件对象 Workbook wb = Workbook.getWorkbook(file);//从文件流中取得Excel工作区对象 Sheet sheet = wb.getSheet(0);//从工作区中取得页,取得这个对象的时候既可以用名称来获得,也可以用序号。 String outPut = ""; outPut = outPut + "<b>" + fileName + "</b><br>"; outPut = outPut + "第一个sheet的名称为:" + sheet.getName() + "<br>"; outPut = outPut + "第一个sheet共有:" + sheet.getRows() + "行" + sheet.getColumns() + "列<br>"; outPut = outPut + "具体内容如下:<br>"; for(int i=0; i < sheet.getRows(); i++){ for(int j=0; j < sheet.getColumns(); j++){ Cell cell = sheet.getCell(j,i); outPut = outPut + cell.getContents() + " "; } outPut = outPut + "<br>"; } out.println(outPut); %> </font> </body> </html>
示例1:读取本地Excel文件F:\红楼人物.xls
1. 新建Excel文件F:\红楼人物.xls
内容如下:
2. Java通过jexcelapi包操作excel文件:
- //in ExcelOperater
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.InputStream;
- import jxl.Cell;
- import jxl.CellType;
- import jxl.Sheet;
- import jxl.Workbook;
- import jxl.write.Label;
- public class ExcelOperater
- {
- public static void main(String[] args)
- {
- jxl.Workbook readwb = null;
- try
- {
- //构建Workbook对象, 只读Workbook对象
- //直接从本地文件创建Workbook
- InputStream instream = new FileInputStream("F:/红楼人物.xls");
- readwb = Workbook.getWorkbook(instream);
- //Sheet的下标是从0开始
- //获取第一张Sheet表
- Sheet readsheet = readwb.getSheet(0);
- //获取Sheet表中所包含的总列数
- int rsColumns = readsheet.getColumns();
- //获取Sheet表中所包含的总行数
- int rsRows = readsheet.getRows();
- //获取指定单元格的对象引用
- for (int i = 0; i < rsRows; i++)
- {
- for (int j = 0; j < rsColumns; j++)
- {
- Cell cell = readsheet.getCell(j, i);
- System.out.print(cell.getContents() + " ");
- }
- System.out.println();
- }
- //利用已经创建的Excel工作薄,创建新的可写入的Excel工作薄
- jxl.write.WritableWorkbook wwb = Workbook.createWorkbook(new File(
- "F:/红楼人物1.xls"), readwb);
- //读取第一张工作表
- jxl.write.WritableSheet ws = wwb.getSheet(0);
- //获得第一个单元格对象
- jxl.write.WritableCell wc = ws.getWritableCell(0, 0);
- //判断单元格的类型, 做出相应的转化
- if (wc.getType() == CellType.LABEL)
- {
- Label l = (Label) wc;
- l.setString("新姓名");
- }
- //写入Excel对象
- wwb.write();
- wwb.close();
- } catch (Exception e) {
- e.printStackTrace();
- } finally {
- readwb.close();
- }
- }
- }
3. 结果:
① 控制台输出:
人物 等级 大观园位置 金陵十二钗
林黛玉 小姐 潇湘馆 正册
妙玉 世外 栊翠庵 正册
晴雯 丫鬟 怡红院 副册
香菱 妾 蘅芜苑 又副册
② 创建文件F:\红楼人物1.xls
4. 程序解析:
所引用的包:
① Workbook对象,需要jxl.Workbook包;
② InputStream、FileInputStream对象:需要java.io.FileInputStream和java.io.InputStream包。
③ Sheet对象:jxl.Sheet包;注意excel中sheet表单的行列从0开始计数。
④ Cell对象:jxl.Cell包;对单元进行处理
⑤ Label:选择jxl.write.label包
⑥ WritableWorkbook、WritableSheet、WritableCelll对象
实例二:3个功能-----从excel文件F:\红楼人物.xls读取数据;生成新的excel文件F:\红楼人物2.xls;修改原excel一个单元并输出为F:\红楼人物3.xls。
原始文件:F:\红楼人物.xls
运行结果:
① 控制台输出:
人物 等级 大观园位置 金陵十二钗
林黛玉 小姐 潇湘馆 正册
妙玉 世外 栊翠庵 正册
晴雯 丫鬟 怡红院 副册
香菱 妾 蘅芜苑 又副册
② 写入输出Excel文件:F:\红楼人物2.xls
③ 修改输出文件 F:\红楼人物3.xls (加修饰后输出)
示例程序:
- //in ExcelHandle
- import jxl.*;
- import jxl.format.UnderlineStyle;
- import jxl.write.*;
- import jxl.write.Number;
- import jxl.write.Boolean;
- import jxl.Cell;
- import java.io.*;
- public class ExcelHandle
- {
- public ExcelHandle()
- {
- }
- /***读取Excel*/
- public static void readExcel(String filePath)
- {
- try
- {
- InputStream is = new FileInputStream(filePath);
- Workbook rwb = Workbook.getWorkbook(is);
- //这里有两种方法获取sheet表:名字和下标(从0开始)
- //Sheet st = rwb.getSheet("original");
- Sheet st = rwb.getSheet(0);
- /**
- //获得第一行第一列单元的值
- Cell c00 = st.getCell(0,0);
- //通用的获取cell值的方式,返回字符串
- String strc00 = c00.getContents();
- //获得cell具体类型值的方式
- if(c00.getType() == CellType.LABEL)
- {
- LabelCell labelc00 = (LabelCell)c00;
- strc00 = labelc00.getString();
- }
- //输出
- System.out.println(strc00);*/
- //Sheet的下标是从0开始
- //获取第一张Sheet表
- Sheet rst = rwb.getSheet(0);
- //获取Sheet表中所包含的总列数
- int rsColumns = rst.getColumns();
- //获取Sheet表中所包含的总行数
- int rsRows = rst.getRows();
- //获取指定单元格的对象引用
- for (int i = 0; i < rsRows; i++)
- {
- for (int j = 0; j < rsColumns; j++)
- {
- Cell cell = rst.getCell(j, i);
- System.out.print(cell.getContents() + " ");
- }
- System.out.println();
- }
- //关闭
- rwb.close();
- }
- catch(Exception e)
- {
- e.printStackTrace();
- }
- }
- /**输出Excel*/
- public static void writeExcel(OutputStream os)
- {
- try
- {
- /** 只能通过API提供的 工厂方法来创建Workbook,而不能使用WritableWorkbook的构造函数,因为类WritableWorkbook的构造函数为 protected类型:方法一:直接从目标文件中读取 WritableWorkbook wwb = Workbook.createWorkbook(new File(targetfile));方法 二:如下实例所示 将WritableWorkbook直接写入到输出流*/
- WritableWorkbook wwb = Workbook.createWorkbook(os);
- //创建Excel工作表 指定名称和位置
- WritableSheet ws = wwb.createSheet("Test Sheet 1",0);
- /**************往工作表中添加数据*****************/
- //1.添加Label对象
- Label label = new Label(0,0,"测试");
- ws.addCell(label);
- //添加带有字型Formatting对象
- WritableFont wf = new WritableFont(WritableFont.TIMES,18,WritableFont.BOLD,true);
- WritableCellFormat wcf = new WritableCellFormat(wf);
- Label labelcf = new Label(1,0,"this is a label test",wcf);
- ws.addCell(labelcf);
- //添加带有字体颜色的Formatting对象
- WritableFont wfc = new WritableFont(WritableFont.ARIAL,10,WritableFont.NO_BOLD,false,
- UnderlineStyle.NO_UNDERLINE,jxl.format.Colour.DARK_YELLOW);
- WritableCellFormat wcfFC = new WritableCellFormat(wfc);
- Label labelCF = new Label(1,0,"Ok",wcfFC);
- ws.addCell(labelCF);
- //2.添加Number对象
- Number labelN = new Number(0,1,3.1415926);
- ws.addCell(labelN);
- //添加带有formatting的Number对象
- NumberFormat nf = new NumberFormat("#.##");
- WritableCellFormat wcfN = new WritableCellFormat(nf);
- Number labelNF = new jxl.write.Number(1,1,3.1415926,wcfN);
- ws.addCell(labelNF);
- //3.添加Boolean对象
- Boolean labelB = new jxl.write.Boolean(0,2,true);
- ws.addCell(labelB);
- Boolean labelB1 = new jxl.write.Boolean(1,2,false);
- ws.addCell(labelB1);
- //4.添加DateTime对象
- jxl.write.DateTime labelDT = new jxl.write.DateTime(0,3,new java.util.Date());
- ws.addCell(labelDT);
- //5.添加带有formatting的DateFormat对象
- DateFormat df = new DateFormat("dd MM yyyy hh:mm:ss");
- WritableCellFormat wcfDF = new WritableCellFormat(df);
- DateTime labelDTF = new DateTime(1,3,new java.util.Date(),wcfDF);
- ws.addCell(labelDTF);
- //6.添加图片对象,jxl只支持png格式图片
- File image = new File("f:\\1.png");
- WritableImage wimage = new WritableImage(0,4,6,17,image);
- ws.addImage(wimage);
- //7.写入工作表
- wwb.write();
- wwb.close();
- }
- catch(Exception e)
- {
- e.printStackTrace();
- }
- }
- /** 将file1拷贝后,进行修改并创建输出对象file2
- * 单元格原有的格式化修饰不能去掉,但仍可将新的单元格修饰加上去,
- * 以使单元格的内容以不同的形式表现
- */
- public static void modifyExcel(File file1,File file2)
- {
- try
- {
- Workbook rwb = Workbook.getWorkbook(file1);
- WritableWorkbook wwb = Workbook.createWorkbook(file2,rwb);//copy
- WritableFont wfc = new WritableFont(WritableFont.ARIAL,10,WritableFont.NO_BOLD,false,
- UnderlineStyle.NO_UNDERLINE,jxl.format.Colour.BLUE);
- WritableCellFormat wcfFC = new WritableCellFormat(wfc);
- WritableSheet ws = wwb.getSheet(0);
- WritableCell wc = ws.getWritableCell(0,0);
- //判断单元格的类型,做出相应的转换
- if(wc.getType() == CellType.LABEL)
- {
- Label labelCF =new Label(0,0,"人物(新)",wcfFC);
- ws.addCell(labelCF);
- //Label label = (Label)wc;
- //label.setString("被修改");
- }
- wwb.write();
- wwb.close();
- rwb.close();
- }
- catch(Exception e)
- {
- e.printStackTrace();
- }
- }
- //测试
- public static void main(String args[])
- {
- try
- {
- //读EXCEL
- ExcelHandle.readExcel("F:/红楼人物.xls");
- //输出EXCEL
- File filewrite=new File("F:/红楼人物2.xls");
- filewrite.createNewFile();
- OutputStream os=new FileOutputStream(filewrite);
- ExcelHandle.writeExcel(os);
- //修改EXCEL
- ExcelHandle.modifyExcel(new File("F:/红楼人物.xls"), new File("F:/红楼人物3.xls"));
- }
- catch(Exception e)
- {
- e.printStackTrace();
- }
- }
- }
附:
调用流程如下:
1.打开工作文件Workbook,在此之前先用java的io流创建或者读取文件
2.打开工作表Sheet
3.读行,然后读列。注意,行和列是从零开始的
4.取得数据进行操作
来自网络à读取Excel数据表
第一步:创建Workbook(术语:工作薄)
2种方法:Workbook,就可以通过它来访问Excel Sheet(术语:工作表):
- //从输入流创建Workbook读取excel数据表
- InputStream is = new FileInputStream(sourcefile);
- jxl.Workbook workbook = Workbook.getWorkbook(is);
- //直接从本地文件(.xls)创建Workbook
- Workbook workbook = Workbook.getWorkbook(new File(excelfile));
一旦创建了
第二步:访问sheet。
2种方法:通过sheet的名称;或者通过下标,下标从0开始。
- //获取第一张Sheet表
- Sheet rs = workbook.getSheet(0);
- 一旦得到了Sheet,就可以通过它来访问Excel Cell(术语:单元格)。
- 第三步:访问单元格cell
- //获取第一行,第一列的值
- Cell c00 = rs.getCell(0, 0);
- String strc00 = c00.getContents();
- //获取第一行,第二列的值
- Cell c10 = rs.getCell(1, 0);
- String strc10 = c10.getContents();
- //获取第二行,第二列的值
- Cell c11 = rs.getCell(1, 1);
- String strc11 = c11.getContents();
- System.out.println("Cell(0, 0)" + " value : " + strc00 + "; type : " + c00.getType());
- System.out.println("Cell(1, 0)" + " value : " + strc10 + "; type : " + c10.getType());
- System.out.println("Cell(1, 1)" + " value : " + strc11 + "; type : " + c11.getType());
第四步:操作数据
如果仅仅是取得Cell的 值,我们可以方便地通过getContents()方法,它可以将任何类型的Cell值都作为一个字符串返回。如果有需要知道Cell内容的确切类型,API也提供了一系列的方法:
- String strc00 = null;
- double strc10 = 0.00;
- Date strc11 = null;
- Cell c00 = rs.getCell(0, 0);
- Cell c10 = rs.getCell(1, 0);
- Cell c11 = rs.getCell(1, 1);
- if(c00.getType() == CellType.LABEL)
- {
- LabelCell labelc00 = (LabelCell)c00;
- strc00 = labelc00.getString();
- }
- if(c10.getType() == CellType.NUMBER)
- {
- NmberCell numc10 = (NumberCell)c10;
- strc10 = numc10.getValue();
- }
- if(c11.getType() == CellType.DATE)
- {
- DateCell datec11 = (DateCell)c11;
- strc11 = datec11.getDate();
- }
- System.out.println("Cell(0, 0)" + " value : " + strc00 + "; type : " + c00.getType());
- System.out.println("Cell(1, 0)" + " value : " + strc10 + "; type : " + c10.getType());
- System.out.println("Cell(1, 1)" + " value : " + strc11 + "; type : " + c11.getType());
在得到
循环取出全部数据,并转化为相应格式:
- int rows = sheet.getRows();
- for (int i = 1; i < rows; i++) {
- Cell cb1 = sheet.getCell(0, i);
- Cell cb2 = sheet.getCell(1, i);
- Cell num3 = sheet.getCell(2, i);
- Cell num4 = sheet.getCell(3, i);
- String user = "";
- String rule = "";
- int numNew = 0;
- int numEdit = 0;
- if (cb1.getType() == CellType.LABEL) {
- LabelCell lc = (LabelCell) cb1;
- user = lc.getString();
- }
- if (cb2.getType() == CellType.LABEL) {
- LabelCell lc = (LabelCell) cb2;
- rule = lc.getString();
- }
- if (num3.getType() == CellType.NUMBER_FORMULA) {
- NumberFormulaCell nc = (NumberFormulaCell) num3;
- try {
- numNew = Double.valueOf(nc.getFormula()).intValue();
- } catch (FormulaException e) {
- e.printStackTrace();
- }
- }
- if (num4.getType() == CellType.NUMBER_FORMULA) {
- NumberFormulaCell nc = (NumberFormulaCell) num4;
- try {
- numEdit = Double.valueOf(nc.getFormula()).intValue();
- } catch (FormulaException e) {
- e.printStackTrace();
- }
- }
- }
第五步:关闭对象,释放内存。
完成对Excel电子表格数据的处理后,一定要使用close()方法来关闭先前创建的对象,以释放读取数据表的过程中所占用的内存空间,在读取大量数据时显得尤为重要。
Cell对象后,通过 getType()方法可以获得该单元格的类型,然后与API提供的基本类型相匹配,强制转换成相应的类型,最后调用相应的取值方法getXXX(),就可以得到确定类型的值。
来自:http://www.cnblogs.com/wuxinrui/archive/2011/03/20/1989326.html
http://www.andykhan.com/jexcelapi/tutorial.html#reading
如果该excel 为计算机生成的,可能该文件仅仅是名字叫xls,但实际不是xls文件。