Java实现读取Excel文件功能(EasyExcel初使用)

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>3.1.1</version>
        </dependency>

@Data
public class ExcelData implements Serializable {
    /**
     * 对应表格的日期列
     */
    private String date;
    /**
     * 对应表格的用户数列
     */
    private Integer userNum;
}

    /**
     * 知道表头，并形成映射关系
     */
    @Test
    public void doImportsForMapping() throws FileNotFoundException{
        // 读取 resource 目录下的 Excel 文件（网站数据.xlsx）
        File file = ResourceUtils.getFile("classpath:网站数据.xlsx");
        // 创建一个 list 存储每行的数据，即 ExcelData 对象
        List<ExcelData> list = new ArrayList<>();
        // 直接使用 EasyExcel 的 read 方法，同时定义表头的类型，以便将列中数据映射为 ExcelData 对象
        EasyExcel.read(file, ExcelData.class, new PageReadListener<ExcelData>(dataList -> {
            // 并且每行数据，并将其 add 至 list 中
            for (ExcelData excelData : dataList) {
                if (excelData != null) {
                    list.add(excelData);
                }
            }
        })).excelType(ExcelTypeEnum.XLSX).sheet().doRead(); // 指定 Excel 的文件后缀，开始分析读取
        for (ExcelData excelData : list) {
            System.out.println(excelData.getDate() + "," + excelData.getUserNum());
        }
    }

 /**
     * 知道表头，并形成映射关系
     * @throws FileNotFoundException
     */
    @Test
    public void doImportsForMappingByInnerClass() throws FileNotFoundException{
        File file = ResourceUtils.getFile("classpath:网站数据.xlsx");
        EasyExcel.read(file, ExcelData.class, new ReadListener<ExcelData>() {

            // 单次缓存的数据量
            public static final int BATCH_COUNT = 2;

            // 临时存储的列表
            private List<ExcelData> cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
            @Override
            public void invoke(ExcelData excelData, AnalysisContext analysisContext) {
                cachedDataList.add(excelData);
                getData(excelData);
                if (cachedDataList.size() >= BATCH_COUNT) {
                    cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
                }
            }

            @Override
            public void doAfterAllAnalysed(AnalysisContext analysisContext) {
                System.out.println("存储数据库成功");
            }

            private void getData(ExcelData excelData) {
                System.out.println(excelData.getDate() + "," + excelData.getUserNum());
            }
        }).excelType(ExcelTypeEnum.XLSX).sheet().doRead();

    }

[{0=日期, 1=用户数}, {0=1号, 1=10}, {0=2号, 1=20}, {0=3号, 1=30}, {0=4号, 1=70}, {0=5号, 1=20}, {0=6号, 1=29}, {0=7号, 1=24}, {0=8号, 1=31}, {0=9号, 1=40}, {0=10号, 1=38}, {0=11号, 1=43}]

    @Test
    public void doImport() throws FileNotFoundException {
        List<Map<Integer, String>> list = null;
        File file = ResourceUtils.getFile("classpath:网站数据.xlsx");
        try {
            list = EasyExcel.read(file)
                    .excelType(ExcelTypeEnum.XLSX)
                    .sheet()
                    .headRowNumber(0)
                    .doReadSync();
        } catch (Exception e) {
            throw new RuntimeException("读取 Excel 文件失败");
        }
        StringBuilder stringBuilder = new StringBuilder();
        for (int i=0;i<list.size();i++) {
            // 转为 LinkedHashMap 主要是为了保证读取的数据和表格顺序一致
            LinkedHashMap<Integer, String> linkedHashMap = (LinkedHashMap) list.get(i);
            List<String> dataList = linkedHashMap.values().stream()
                    .filter(ObjectUtils::isNotEmpty).collect(Collectors.toList());
            stringBuilder.append(StringUtils.join(dataList, ",")).append("\n");
        }
        System.out.println(stringBuilder.toString());
    }