1.导出一个excel文件，写入内容：

package poi;import org.apache.poi.hssf.usermodel.*;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.util.Date;/** */public class POICreateTest {    public static void main(String args[]){        HSSFWorkbook wb=new HSSFWorkbook();        HSSFSheet sheet=wb.createSheet("new sheet");        HSSFRow row=sheet.createRow((short)0);        HSSFCell cell=row.createCell((short)0);        cell.setCellValue(1);        row.createCell((short)1).setCellValue(1.2);        row.createCell((short) 2).setCellValue("test");        row.createCell((short) 3).setCellValue(true);        HSSFCellStyle cellStyle=wb.createCellStyle();        cellStyle.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));        HSSFCell dCell=row.createCell((short) 4);        dCell.setCellValue(new Date());        dCell.setCellStyle(cellStyle);        HSSFCell csCell=row.createCell((short) 5);        csCell.setCellType(HSSFCell.ENCODING_UTF_16);        csCell.setCellValue("你好啊——hello");        row.createCell((short) 6).setCellType(HSSFCell.CELL_TYPE_ERROR);        try {            FileOutputStream fileOut=new FileOutputStream("D:\\workbook.xls");            try {                wb.write(fileOut);                fileOut.close();            } catch (IOException e) {                e.printStackTrace();            }        } catch (FileNotFoundException e) {            e.printStackTrace();        }    }}

2.导入一个excel，读取其中的内容：

package poi;import org.apache.poi.hssf.usermodel.HSSFCell;import org.apache.poi.hssf.usermodel.HSSFDateUtil;import org.apache.poi.hssf.usermodel.HSSFSheet;import org.apache.poi.hssf.usermodel.HSSFWorkbook;import org.apache.poi.ss.usermodel.Cell;import org.apache.poi.ss.usermodel.Row;import java.io.FileInputStream;import java.io.IOException;import java.text.DateFormat;import java.text.SimpleDateFormat;import java.util.Date;/** */public class POIReadTest {    public static String file="D:\\workbook.xls";    public static void main(String args[]){        try {            HSSFWorkbook workbook=new HSSFWorkbook(new FileInputStream(file));            HSSFSheet sheet=workbook.getSheetAt(0);            //遍历行            for (Row row:sheet){                for(Cell cell:row){                    System.out.print(formatPOI((HSSFCell) cell)+"   ");                }                System.out.println("");            }        } catch (IOException e) {            e.printStackTrace();        }    }    public static String formatPOI(HSSFCell cell){        switch (cell.getCellType()){            case HSSFCell.CELL_TYPE_BOOLEAN:                return String.valueOf(cell.getBooleanCellValue());            case HSSFCell.CELL_TYPE_ERROR:                return "this data is error";            case HSSFCell.CELL_TYPE_NUMERIC:                if (HSSFDateUtil.isCellDateFormatted(cell)){                    Date date=cell.getDateCellValue();                    DateFormat dateFormat=new SimpleDateFormat("m/d/yy h:mm");                    return dateFormat.format(date).toString();                }else {                    return String.valueOf(cell.getNumericCellValue());                }            case HSSFCell.CELL_TYPE_STRING:                return cell.getStringCellValue();            default:                return "bad errors!!!";        }    }}