import java.io.File;

import java.io.FileOutputStream;

import org.apache.commons.io.FileUtils;

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

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

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

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

public class PoiExpExcel {

    public static void main(String[] args) {

        String[] title={"ID","用户","密码"};

        //创建Excel工作薄

        HSSFWorkbook workbook=new HSSFWorkbook();

        //创建一个工作表sheet

        HSSFSheet sheet=workbook.createSheet();

        //创建第一行

        HSSFRow row= sheet.createRow(0);

        HSSFCell cell=null;

        //插入第一行数据

        for (int i = 0; i < title.length; i++) {

            cell=row.createCell(i);

            cell.setCellValue(title[i]);

        }

        //追加数据

        for (int i = 0; i < 10; i++) {

            HSSFRow nextrow=sheet.createRow(i);

            //第一个单元格

            HSSFCell cell2=nextrow.createCell(0);

            cell2.setCellValue("a"+i);

            //第二个单元格

            cell2=nextrow.createCell(1);

            cell2.setCellValue("小明"+i);

            //第三个单元格

            cell2=nextrow.createCell(2);

            cell2.setCellValue("123456");

        }

        //创建一个文件

        File file=new File("e:/poi_test.xls");

        try {

            file.createNewFile();

            //写入硬盘

            FileOutputStream stream=FileUtils.openOutputStream(file);

            workbook.write(stream);

            stream.close();

        } catch (Exception e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

}

import java.io.File;

import java.io.IOException;

import org.apache.commons.io.FileUtils;

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

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

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

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

public class PoiReaderExcel {

    public static void main(String[] args) {

        File file=new File("e:/poi_test.xls");

        try {

            //创建Excel,读取文件

            HSSFWorkbook workbook=new HSSFWorkbook(FileUtils.openInputStream(file));

            //获取第一张工作表 ：通过名字获取

//            HSSFSheet sheet=workbook.getSheet("sheet0");

            //读取默认的第一张工作页

            HSSFSheet sheet=workbook.getSheetAt(0);

            //读取分步骤详细

            int FirstRowNum=sheet.getFirstRowNum();

            int LastRowNum=sheet.getLastRowNum();

            for (int i = FirstRowNum; i < LastRowNum; i++) {

                HSSFRow row=sheet.getRow(i);

                int FirstCellNum=row.getFirstCellNum();

                int LastCellNum=row.getLastCellNum();

                for (int j = FirstCellNum; j < LastCellNum; j++) {

                    HSSFCell cell=row.getCell(j);

                    System.out.print(cell.getStringCellValue()+"  ");

                }

                System.out.println();

            }

//            for (int i = 0; i < sheet.getLastRowNum(); i++) {

//                for (int j = 0; j < sheet.getRow(i).getLastCellNum(); j++) {

//                    System.out.print(sheet.getRow(i).getCell(j).getStringCellValue()+" ");

//                }

//                System.out.println();

//            }

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

}