java读取和输出excel表格的问题
java.lang.ClassCastException: jxl.write.Number cannot be cast to jxl.write.Label
at CreateXL.updateExcel(CreateXL.java:34)
at CreateXL.main(CreateXL.java:21)
请高手帮忙指点一下，谢谢
import java.io.*;
import java.util.Random;
import java.util.Date;
import jxl.*;
import jxl.format.UnderlineStyle;
import jxl.write.*;
import jxl.write.Number;
import jxl.write.Boolean;
public class CreateXL
{
public CreateXL()
{
}
public static void main(String[] args)
{
//读Excel
CreateXL.readExcel("f:/1.xls");
//更新Excel
CreateXL.updateExcel("d:/new.xls");
}
//jxl暂时不提供修改已经存在的数据表,这里通过一个小办法来达到这个目的,不适合大型数据更新!
//这里是通过覆盖原文件来更新的.
public static void updateExcel(String filePath)
{
try{
Workbook rwb = Workbook.getWorkbook(new File("f:/1.xls"));
WritableWorkbook wwb = Workbook.createWorkbook(new File(filePath),rwb);//copy
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
Label label = (Label)wc;
label.setString("The value has been modified");
wwb.write();
wwb.close();
rwb.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public static void readExcel(String filePath)
{
/**
*后续考虑问题,比如Excel里面的图片以及其他数据类型的读取
**/
try
{
InputStream is=new FileInputStream(filePath);
//声名一个工作薄
Workbook rwb = Workbook.getWorkbook(is);
//获得工作薄的个数
rwb.getNumberOfSheets();
//在Excel文档中，第一张工作表的缺省索引是0
Sheet st = rwb.getSheet("Sheet1");
//通用的获取cell值的方式,getCell(int column, int row) 行和列
int Rows=st.getRows();
int Cols=st.getColumns();
System.out.println("当前工作表的名字:"+st.getName());
System.out.println("总行数:"+Rows);
System.out.println("总列数:"+Cols);
Cell c;
for(int j=0;j<Cols;j++)
{
for(int i=0;i<Rows;i++)
{
//getCell(Col,Row)获得单元格的值
System.out.print((st.getCell(j,i)).getContents()+"\t");
}
System.out.print("\n");
}
//操作完成时，关闭对象，释放占用的内存空间
rwb.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
} 展开
Java Excel 是一个开源项目，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文件等，在项目中需要导入名为jxl.jar的包。在这里只是示例它的基本用法，其他高级的功能（图片、公式、格式等）请参考Java Excel的帮助文档。
如有一个用户资料的Excel表，包含ID、用户名、性别、邮件等信息，定义一个用户JavaBean：
package com.monitor1394.excel;
/**
*
* 用户
*
* @author monitor
* Created on 2010-12-22, 9:57:58
*/
public class User {
/** ID */
private int id;
/** 用户名 */
private String name;
/** 性别 1:男 2:女*/
private int sex;
/** 邮件 */
private String email;
public User(){
}
public User(int id,String name,int sex,String email){
this.id=id;
this.name=name;
this.sex=sex;
this.email=email;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
@Override
public String toString(){
return id+":"+name;
}
}
提供的Excel表操作类如下，某些单元格的格式可按自己意愿指定：
package com.monitor1394.excel;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import jxl.Sheet;
import jxl.Workbook;
import jxl.format.Alignment;
import jxl.format.Border;
import jxl.format.BorderLineStyle;
import jxl.format.Colour;
import jxl.format.VerticalAlignment;
import jxl.read.biff.BiffException;
import jxl.write.Label;
import jxl.write.Number;
import jxl.write.NumberFormats;
import jxl.write.WritableCellFormat;
import jxl.write.WritableFont;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;
/**
*
* Excel表操作
*
* @author monitor
* Created on 2010-12-22, 9:50:28
*/
public class Excel {
/** 标题单元格格式 */
private static WritableCellFormat titleFormat=null;
/** 主题内容单元格格式 */
private static WritableCellFormat bodyFormat=null;
/** 注释单元格格式 */
private static WritableCellFormat noteFormat=null;
/** 浮点型数据的单元格格式 */
private static WritableCellFormat floatFormat=null;
/** 整型数据的单元格格式 */
private static WritableCellFormat intFormat=null;
/** 初始化数据 */
private static boolean init=false;
/** 私有构造方法，防止错误使用Excel类 */
private Excel(){
}
/**
* 初始化各单元格格式
* @throws WriteException 初始化失败
*/
private static void init() throws WriteException{
WritableFont font1,font2,font3,font4;
//Arial字体，9号，粗体，单元格黄色，田字边框，居中对齐
font1 = new WritableFont(WritableFont.ARIAL, 9, WritableFont.BOLD, false);
titleFormat = new WritableCellFormat (font1);
titleFormat.setBackground(Colour.YELLOW);
titleFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
titleFormat.setAlignment(Alignment.CENTRE);
//Arial字体，9号，粗体，单元格黄色，田字边框，左右居中对齐，垂直居中对齐，自动换行
font2 = new WritableFont(WritableFont.ARIAL, 9, WritableFont.BOLD, false);
noteFormat = new WritableCellFormat (font2);
noteFormat.setBackground(Colour.YELLOW);
noteFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
noteFormat.setAlignment(Alignment.CENTRE);
noteFormat.setVerticalAlignment(VerticalAlignment.CENTRE);
noteFormat.setWrap(true);
//Arial字体，9号，非粗体，单元格淡绿色，田字边框
font3 = new WritableFont(WritableFont.ARIAL, 9, WritableFont.NO_BOLD, false);
bodyFormat = new WritableCellFormat (font3);
bodyFormat.setBackground(Colour.LIGHT_GREEN);
bodyFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
//Arial字体，9号，非粗体，单元格淡绿色，田字边框
font4 = new WritableFont(WritableFont.ARIAL, 9, WritableFont.NO_BOLD, false);
floatFormat = new WritableCellFormat (font4,NumberFormats.FLOAT);
floatFormat.setBackground(Colour.LIGHT_GREEN);
floatFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
//Arial字体，9号，非粗体，单元格淡绿色，田字边框
font4 = new WritableFont(WritableFont.ARIAL, 9, WritableFont.NO_BOLD, false);
intFormat = new WritableCellFormat (font4,NumberFormats.INTEGER);
intFormat.setBackground(Colour.LIGHT_GREEN);
intFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
init=true;
}
public static void createUserExcelFile(List<User> userList,File destFile) throws WriteException, IOException{
if(init==false) init();
int index,row;
WritableSheet sheet=null;
WritableWorkbook book=null;
book = Workbook.createWorkbook(destFile);
sheet = book.createSheet("用户表", 0);
sheet.setColumnView(0, 15);
sheet.setColumnView(1, 15);
sheet.setColumnView(2, 15);
sheet.setColumnView(3, 40);
//字段变量名
index=0;
sheet.addCell(new Label(index++,0,"id",titleFormat));
sheet.addCell(new Label(index++,0,"name",titleFormat));
sheet.addCell(new Label(index++,0,"sex",titleFormat));
sheet.addCell(new Label(index++,0,"email",titleFormat));
//字段名
index=0;
sheet.addCell(new Label(index++,1,"ID",titleFormat));
sheet.addCell(new Label(index++,1,"用户名",titleFormat));
sheet.addCell(new Label(index++,1,"性别",titleFormat));
sheet.addCell(new Label(index++,1,"邮件",titleFormat));
//字段注释
index=0;
sheet.addCell(new Label(index++,2,null,noteFormat));
sheet.addCell(new Label(index++,2,null,noteFormat));
sheet.addCell(new Label(index++,2,"1:男/n2:女",noteFormat));
sheet.addCell(new Label(index++,2,null,noteFormat));
row=3;
for(User user:userList){
if(user==null) continue;
index=0;
sheet.addCell(new Number(index++,row,user.getId(),bodyFormat));
sheet.addCell(new Label(index++,row,user.getName(),bodyFormat));
sheet.addCell(new Number(index++,row,user.getSex(),bodyFormat));
sheet.addCell(new Label(index++,row,user.getEmail(),bodyFormat));
row++;
}
book.write();
if(book!=null) book.close();
}
public static List<User> readUserExcelFile(File file) throws IOException, BiffException{
if(file==null) return null;
int row,column;
String temp=null;
Workbook book =null;
Sheet sheet=null;
List<User> userList=new ArrayList<User>();
book = Workbook.getWorkbook(file);
sheet = book.getSheet(0);
row=3;
while(row<sheet.getRows()){
column=0;
User user=new User();
//id
temp=sheet.getCell(column++,row).getContents().trim();
if(temp!=null && !temp.equals("") && temp.matches("//d+")) user.setId(Integer.parseInt(temp));
else break;
//名称
temp=sheet.getCell(column++,row).getContents().trim();
if(temp!=null && !temp.equals("")) user.setName(temp);
//性别
temp=sheet.getCell(column++,row).getContents().trim();
if(temp!=null && !temp.equals("") && temp.matches("//d+")) user.setSex(Integer.parseInt(temp));
//邮件
temp=sheet.getCell(column++,row).getContents().trim();
if(temp!=null && !temp.equals("")) user.setEmail(temp);
userList.add(user);
row++;
}
if(book!=null) book.close();
return userList;
}
}
要导入的Excel表格式如下：
导出后的Excel表如下：
类型转换错误
你看报错的34行是这句吗？
WritableCell wc = ws.getWritableCell(0,0);
//判断单元格的类型,做出相应的转换
Label label = (Label)wc;
ws.getWritableCell(0,0);这句取出的应该是Number型的吧？
试试用Number作转换，Number nc = (Number)wc
遇到这样的情况可以先判断是哪种类型，再考虑怎么作转换，eg:
if(cell.getType()==CellType.NUMBER){
System.out.print(((NumberCell)cell).getValue());
}else if(cell.getType()==CellType.DATE){
System.out.print(((DateCell)cell).getDate());
}
以上，如有不对之处，请斧正
//判断单元格的类型,做出相应的转换
Label label = (Label)wc;
label.setString("The value has been modified");
应该是这里判断类型出错了，你的1.xls文件中的sheet1表中的A1内容一定是数字，改为别的文本就不会出错了。
Label label = (Label)wc;
label.setString("The value has been modified");
改成Label label2=new Label(0,0,"test");
ws.addCell(label2);
就好了，不用管原先是什么类型的。
