java poi

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ReadExcel {
	public static void main(String[] args) throws IOException {

		// File file = new File("C:/Users.xlsx");
		InputStream stream = new FileInputStream(
				"E:\\123.xlsx");

		XSSFWorkbook xssfWorkbook = new XSSFWorkbook(stream);
		XSSFSheet xssfSheet = xssfWorkbook.getSheetAt(0);

		int rowstart = xssfSheet.getFirstRowNum();
		int rowEnd = xssfSheet.getLastRowNum();
		for (int i = rowstart; i <= rowEnd; i++) {
			XSSFRow row = xssfSheet.getRow(i);
			if (null == row)
				continue;
			int cellStart = row.getFirstCellNum();
			int cellEnd = row.getLastCellNum();

			for (int k = cellStart; k <= cellEnd; k++) {
				XSSFCell cell = row.getCell(k);
				if (null == cell)
					continue;

				switch (cell.getCellType()) {
				case HSSFCell.CELL_TYPE_NUMERIC: // 数字
					System.out.print(cell.getNumericCellValue() + "\t");
					break;
				case HSSFCell.CELL_TYPE_STRING: // 字符串
					System.out.print(cell.getStringCellValue() + "\t");
					break;
				case HSSFCell.CELL_TYPE_BOOLEAN: // Boolean
					System.out.println(cell.getBooleanCellValue() + "\t");
					break;
				case HSSFCell.CELL_TYPE_FORMULA: // 公式
					System.out.print(cell.getCellFormula() + "\t");
					break;
				case HSSFCell.CELL_TYPE_BLANK: // 空值
					System.out.println(" ");
					break;
				case HSSFCell.CELL_TYPE_ERROR: // 故障
					System.out.println(" ");
					break;
				default:
					System.out.print("未知类型   ");
					break;
				}

			}
			System.out.print("\n");
		}
	}
}

　

　读取xls

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

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;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;

public class ReadXls {
    public static void main(String[] args) throws IOException, IOException {
        File file = new File("E:\\123.xls");
        POIFSFileSystem poifsFileSystem = new POIFSFileSystem(
                new FileInputStream(file));
        HSSFWorkbook hssfWorkbook = new HSSFWorkbook(poifsFileSystem);
        HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(0);

        int rowstart = hssfSheet.getFirstRowNum();
        int rowEnd = hssfSheet.getLastRowNum();
        for (int i = rowstart; i <= rowEnd; i++) {
            HSSFRow row = hssfSheet.getRow(i);
            if (null == row)
                continue;
            int cellStart = row.getFirstCellNum();
            int cellEnd = row.getLastCellNum();

            for (int k = cellStart; k <= cellEnd; k++) {
                HSSFCell cell = row.getCell(k);
                if (null == cell)
                    continue;
                // System.out.print("" + k + "  ");
                // System.out.print("type:"+cell.getCellType());

                switch (cell.getCellType()) {
                case HSSFCell.CELL_TYPE_NUMERIC: // 数字
                    System.out.print(cell.getNumericCellValue() + "   ");
                    break;
                case HSSFCell.CELL_TYPE_STRING: // 字符串
                    System.out.print(cell.getStringCellValue() + "   ");
                    break;
                case HSSFCell.CELL_TYPE_BOOLEAN: // Boolean
                    System.out.println(cell.getBooleanCellValue() + "   ");
                    break;
                case HSSFCell.CELL_TYPE_FORMULA: // 公式
                    System.out.print(cell.getCellFormula() + "   ");
                    break;
                case HSSFCell.CELL_TYPE_BLANK: // 空值
                    System.out.println(" ");
                    break;
                case HSSFCell.CELL_TYPE_ERROR: // 故障
                    System.out.println(" ");
                    break;
                default:
                    System.out.print("未知类型   ");
                    break;
                }

            }
            System.out.print("\n");
        }
    }
}

异常：Invalid header signature POI

这一般是由于第三方工具自动生成的excel文件的文件不太规范，你可以手动打开Excel(如果可以打开)再另存为-》保存Excel就可以了