java POI读取excel

POI读取excel2003和2007方法是一样的，主要就是用得类不同而已，读取excel2003只需要一个jar包，而读取2007则需要poi3.5以上版本里面的所有jar包，下面将提供代码和jar：

/**
 * Excel工具类
 * @author Administrator
 *
 */
public class Excel {

	private Workbook workbook;
	
	public Workbook getWorkbook() {
		return workbook;
	}

	public void setWorkbook(Workbook workbook) {
		this.workbook = workbook;
	}
	
	public Excel(File file) {
		InputStream is = null;
		POIFSFileSystem ps = null;
		try {
			is = new FileInputStream(file);
			try{
				ps = new POIFSFileSystem(is);
				this.workbook = new HSSFWorkbook(ps);
			}catch (Exception e) {
				try {
					OPCPackage opcPackage = OPCPackage.openOrCreate(file);
					this.workbook = new XSSFWorkbook(opcPackage);
				} catch (Exception e2) {
					e2.printStackTrace();
					System.out.println("要读取的excel文件必须为2003或2007格式");
				}
			}	
		} catch (FileNotFoundException e) {
			System.out.println("找不到文件");
			e.printStackTrace();
		} finally {
			try {
				is.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	

	public Sheet getSheet(String sheetName) {
		return workbook.getSheet(sheetName);
	}

	/**
	 * 根据列名得到值
	 * 
	 * @param columnName
	 * @return
	 */
	public String getValue(int rowIndex, int cellIndex) throws Exception {
		String returnValue = "";
		DecimalFormat decimalFormat = new DecimalFormat("#");
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
		Sheet sheet = workbook.getSheetAt(0);
		Row row = sheet.getRow(rowIndex);
		Cell cell = null;
		if (row != null) {
			cell = row.getCell(cellIndex);
			if (cell != null) {
				switch (cell.getCellType()) {
					case HSSFCell.CELL_TYPE_NUMERIC: // 数值型
						if (HSSFDateUtil.isCellDateFormatted(cell)) {// 如果是date类型则 ，获取该cell的date值
							returnValue = dateFormat.format(HSSFDateUtil.getJavaDate(cell.getNumericCellValue()));
						} else {// 纯数字
							returnValue = decimalFormat.format(cell.getNumericCellValue());
						}
						break;
						
					/* 此行表示单元格的内容为string类型 */
					case HSSFCell.CELL_TYPE_STRING: // 字符串型
						
						returnValue = cell.getRichStringCellValue().toString();
						break;
						
					case HSSFCell.CELL_TYPE_FORMULA:// 公式型
						// 读公式计算值
						returnValue = String.valueOf(cell.getNumericCellValue());
						if (returnValue.equals("NaN")) {// 如果获取的数据值为非法值,则转换为获取字符串
							returnValue = cell.getRichStringCellValue().toString();
						}
						// cell.getCellFormula();读公式
						break;
						
					case HSSFCell.CELL_TYPE_BOOLEAN:// 布尔
						returnValue = "" + cell.getBooleanCellValue();
						break;
						
					/* 此行表示该单元格值为空 */
					case HSSFCell.CELL_TYPE_BLANK: // 空值
						returnValue = "";
						break;
						
					case HSSFCell.CELL_TYPE_ERROR: // 故障
						returnValue = "";
						break;
						
					default:
						returnValue = cell.getRichStringCellValue().toString();
				}
			} else {
				returnValue = "";
			}
		}else{
			returnValue = "";
		}
		return returnValue;
	}

	/**
	 * 得到所有的记录数
	 * 
	 * @return
	 */
	public int getRowCount() {
		return workbook.getSheetAt(0).getLastRowNum();
	}

	/**
	 * 得到Excel表里面的字段名
	 * 
	 * @return
	 */
	public List<String> getColumnNames() {
		List<String> columnNames = new ArrayList<String>();

		Sheet sheet = workbook.getSheetAt(0);
		Row columnNameRow = sheet.getRow(0);
		for (int i = 0; i < columnNameRow.getLastCellNum(); i++) {
			columnNames.add(columnNameRow.getCell(i).getStringCellValue());
		}
		return columnNames;
	}
	
	public static void main(String[] args) {
		Excel excel = new Excel(new File("D:\\23.xlsx"));
		System.out.println(excel.getRowCount());
	}
}