java读写excel文件xlsx

Java读写Excel文件可以使用Apache POI库，下面是一个简单的读写Excel文件的示例代码：

1. 读取Excel文件

public static void readExcelFile(String filePath) {
    try {
        FileInputStream file = new FileInputStream(new File(filePath));
        XSSFWorkbook workbook = new XSSFWorkbook(file);
        XSSFSheet sheet = workbook.getSheetAt(0);
        Iterator<Row> rowIterator = sheet.iterator();
        while (rowIterator.hasNext()) {
            Row row = rowIterator.next();
            Iterator<Cell> cellIterator = row.cellIterator();
            while (cellIterator.hasNext()) {
                Cell cell = cellIterator.next();
                switch (cell.getCellType()) {
                    case STRING:
                        System.out.print(cell.getStringCellValue() + "\t");
                        break;
                    case NUMERIC:
                        System.out.print(cell.getNumericCellValue() + "\t");
                        break;
                    case BOOLEAN:
                        System.out.print(cell.getBooleanCellValue() + "\t");
                        break;
                    default:
                }
            }
            System.out.println("");
        }
        file.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

2. 写入Excel文件

public static void writeExcelFile(String filePath) {
    XSSFWorkbook workbook = new XSSFWorkbook();
    XSSFSheet sheet = workbook.createSheet("Sheet1");
    Object[][] data = {
            {"Name", "Age", "Gender"},
            {"Tom", 20, "Male"},
            {"Lucy", 18, "Female"},
            {"Jack", 22, "Male"},
            {"Lily", 21, "Female"}
    };
    int rowNum = 0;
    for (Object[] rowData : data) {
        Row row = sheet.createRow(rowNum++);
        int colNum = 0;
        for (Object field : rowData) {
            Cell cell = row.createCell(colNum++);
            if (field instanceof String) {
                cell.setCellValue((String) field);
            } else if (field instanceof Integer) {
                cell.setCellValue((Integer) field);
            }
        }
    }
    try {
        FileOutputStream outputStream = new FileOutputStream(filePath);
        workbook.write(outputStream);
        outputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

注意：在使用POI库之前，需要先引入相关的依赖。