Java 使用POI读取导入Excel的工具类

package com.cjavapy.utils.util;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.multipart.MultipartFile;
import java.io.FileInputStream;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
/**
 * Excel导入工具类
 *
 */
public class ImportExcelUtils {
    /**
     * 创建WorkBook对象
     *
     * @param filePath
     * @return
     * @throws IOException
     */
    public static final Workbook createWorkbook(String filePath) throws IOException {
        if (filePath.trim().toLowerCase().endsWith("xls")) {
            return new XSSFWorkbook(new FileInputStream(filePath));
        } else if (filePath.trim().toLowerCase().endsWith("xlsx")) {
            return new XSSFWorkbook(new FileInputStream(filePath));
        } else {
            throw new IllegalArgumentException("不是有效的excel文件格式");
        }
    }
    /**
     * 创建WorkBook对象
     *
     * @param uploadFile
     * @return
     * @throws IOException
     */
    public static final Workbook createWorkbook(MultipartFile uploadFile) throws IOException {
        return new XSSFWorkbook(uploadFile.getInputStream());
    }
    /**
     * 获取Sheet页面(按名称)
     *
     * @param wb
     * @param sheetName
     * @return
     */
    public static final Sheet getSheet(Workbook wb, String sheetName) {
        return wb.getSheet(sheetName);
    }
    /**
     * 获取Sheet页面(按页标)
     *
     * @param wb
     * @param index
     * @return
     */
    public static final Sheet getSheet(Workbook wb, int index) {
        return wb.getSheetAt(index);
    }
    /**
     * 获取Sheet页内容
     *
     * @param sheet
     * @return
     */
    public static final List<Object[]> listFromSheet(Sheet sheet) {
        List<Object[]> list = new ArrayList<Object[]>();
        for (int r = sheet.getFirstRowNum(); r <= sheet.getLastRowNum(); r++) {
            Row row = sheet.getRow(r);
            if (row == null || row.getPhysicalNumberOfCells() == 0) continue;
            Object[] cells = new Object[row.getLastCellNum()];
            for (int c = row.getFirstCellNum(); c <= row.getLastCellNum(); c++) {
                Cell cell = row.getCell(c);
                if (cell == null) continue;
                //判断是否为日期类型
                cells[c] = getValueFromCell(cell);
            }
            list.add(cells);
        }
        return list;
    }
    /**
     * 获取单元格内信息
     *
     * @param cell
     * @return
     */
    public static final Object getValueFromCell(Cell cell) {
        if (cell == null) {
            //System.out.println("Cell is null !!!");
            return null;
        }
        Object result = null;
        if (cell instanceof HSSFCell) {
            if (cell != null) {
                // 单元格类型：Numeric:0,String:1,Formula:2,Blank:3,Boolean:4,Error:5
                int cellType = ((HSSFCell) cell).getCellType();
                switch (cellType) {
                    case HSSFCell.CELL_TYPE_STRING:
                        result = ((HSSFCell) cell).getStringCellValue();
                        break;
                    case HSSFCell.CELL_TYPE_NUMERIC:
                        DecimalFormat df = new DecimalFormat("###.####");
                        result = df.format(((HSSFCell) cell).getNumericCellValue());
                        break;
                    case HSSFCell.CELL_TYPE_FORMULA:
                        result = ((HSSFCell) cell).getNumericCellValue();
                        break;
                    case HSSFCell.CELL_TYPE_BOOLEAN:
                        result = ((HSSFCell) cell).getBooleanCellValue();
                        break;
                    case HSSFCell.CELL_TYPE_BLANK:
                        result = null;
                        break;
                    case HSSFCell.CELL_TYPE_ERROR:
                        result = null;
                        break;
                    default:
                        System.out.println("枚举了所有类型");
                        break;
                }
            }
        } else if (cell instanceof XSSFCell) {
            if (cell != null) {
                // 单元格类型：Numeric:0,String:1,Formula:2,Blank:3,Boolean:4,Error:5
                int cellType = ((XSSFCell) cell).getCellType();
                switch (cellType) {
                    case XSSFCell.CELL_TYPE_STRING:
                        result = ((XSSFCell) cell).getRichStringCellValue().getString();
                        break;
                    case XSSFCell.CELL_TYPE_NUMERIC:
                        DecimalFormat df = new DecimalFormat("###.####");
                        result = df.format(((XSSFCell) cell).getNumericCellValue());
                        break;
                    case XSSFCell.CELL_TYPE_FORMULA:
                        result = ((XSSFCell) cell).getNumericCellValue();
                        break;
                    case XSSFCell.CELL_TYPE_BOOLEAN:
                        result = ((XSSFCell) cell).getBooleanCellValue();
                        break;
                    case XSSFCell.CELL_TYPE_BLANK:
                        result = null;
                        break;
                    case XSSFCell.CELL_TYPE_ERROR:
                        result = null;
                        break;
                    default:
                        //System.out.println("枚举了所有类型");
                        break;
                }
            }
        }
        return result;
    }
    /**
     * 根据Sheet页导入Excel信息
     *
     * @param filePath   文件路径
     * @param sheetIndex Sheet页下标
     * @param startRow   开始列 ：默认第一列
     * @param startLine  开始行 ：默认第一行
     * @throws Exception
     */
    public static final List<Object[]> importExcelBySheetIndex(String filePath, int sheetIndex
            , int startRow, int startLine) throws Exception {
        List<Object[]> resultList = null;
        //创建WorkBook对象
        Workbook wb = createWorkbook(filePath);
        // 获取Sheet
        Sheet sheet = ImportExcelUtils.getSheet(wb, sheetIndex);
        // 判断Sheet是否为空
        if (sheet != null) {
            // 遍历Sheet
            List<Object[]> list = ImportExcelUtils.listFromSheet(sheet);
            if (list != null && list.size() > 0) {
                resultList = new ArrayList<Object[]>();
                if (startLine <= list.size()) {
                    for (int i = startLine; i < list.size(); i++) {
                        int nullCount = 0;
                        Object[] rows = list.get(i);
                        if (rows != null && rows.length > 0) {
                            List<Object> resultObjects = new ArrayList<Object>();
                            for (int n = startRow; n < rows.length; n++) {
                                if (Assert.objIsEmpty(rows[n])) {
                                    nullCount++;
                                }
                                resultObjects.add(rows[n]);
                            }
                            //判断空的单元格个数
                            if (nullCount >= rows.length) {
                                break;
                            } else {
                                resultList.add(resultObjects.toArray());
                            }
                        }
                    }
                }
            }
        }
        return resultList;
    }
}