一文带你轻松掌握EasyExcel的使用技巧

//读取指定Sheet
List<YourModelName> list = EasyExcel.read(fileName)
.sheet(sheetNo)
.head(YourModelName.class)
.doReadSync();

//读取指定列
List<Object> list = EasyExcel.read(fileName)
.sheet(sheetNo)
.headRow(rowNo)
.readRowFilter(new ReadRowFilter() {
    @Override
    public boolean doFilter(List<Object> list) {
        if (list.get(0).equals("某一列的值")) {
            return true;
        }
        return false;
    }
})
.doReadSync();

//向指定Sheet写入数据
ExcelWriter excelWriter = null;
try {
    excelWriter = EasyExcel.write(fileName, YourModelName.class).build();
    WriteSheet writeSheet = EasyExcel.writerSheet(sheetNo).build();
    excelWriter.write(dataList, writeSheet);
} finally {
    if (excelWriter != null) {
        excelWriter.finish();
    }
}

//向指定行写入数据
ExcelWriter excelWriter = null;
try {
    excelWriter = EasyExcel.write(fileName, YourModelName.class).build();
    WriteSheet writeSheet = EasyExcel.writerSheet(sheetNo).build();
    excelWriter.write(dataList, writeSheet, new WriteTable()) .relativeHeadRowIndex(rowNo) .doWrite();
} finally {
    if (excelWriter != null) {
        excelWriter.finish();
    }
}

//对象填充
List<YourModelName> dataList = getDataList();
OutputStream outputStream = new FileOutputStream(fileName);
EasyExcel.write(outputStream, YourModelName.class)
    .sheet(sheetNo)
    .doWrite(dataList);
outputStream.close();

//自定义填充
List<Object> headList = getHeadList();
List<List<Object>> dataList = getDataList();
ExcelWriter excelWriter = null;
try {
    excelWriter = EasyExcel.write(fileName).build();
    WriteSheet writeSheet = EasyExcel.writerSheet(sheetNo).build();
    FillConfig fillConfig = FillConfig.builder().direction(WriteDirectionEnum.VERTICAL).build();
    excelWriter.fill(headList, fillConfig, writeSheet);
    excelWriter.fill(dataList, fillConfig, writeSheet);
} finally {
    if (excelWriter != null) {
        excelWriter.finish();
    }
}

//禁止EasyExcel对单元格内容进行trim操作
Object value = cell.getStringCellValue();
cell.setCellValue(new HSSFRichTextString(value.toString()));

//异步读取
EasyExcel.read(fileName, YourModelName.class, new ReadListener<YourModelName>() {
    // 重写方法
}).sheet().doRead();

public class ExcelReader<T> {
    private static final Logger LOGGER = LoggerFactory.getLogger(ExcelReader.class);
    private Sheet sheet;
    private Workbook workbook;
    private Class<T> currentSheetClazz;
    // 省略部分成员变量及构造方法
}

public void read(ReadSheet readSheet) {
    try {
        readSheet.setClazz(currentSheetClazz);
        readSheet.init();
        process(readSheet);
    } finally {
        if (workbook != null) {
            try {
                workbook.close();
            } catch (IOException e) {
                LOGGER.warn("Close IO exception ,msg is {}", e.getMessage());
            }
        }
    }
}

private void process(ReadSheet readSheet) {
    // 从Excel文件中读取所有的数据行
    List<List<String>> rows = readSheet.getHead() == null ? sheet2List() : sheet2List(readSheet.getStartSheetIndex(), readSheet.getEndSheetIndex());
    // 获取Java类中用于映射Excel中数据的属性列表
    List<Field> fieldList = ReflectionUtil.getFieldListWithExcelColumn(currentSheetClazz);
    // 缓存读取到的Java对象列表
    List<T> dataList = new ArrayList<>();
    if (CollectionUtils.isEmpty(rows)) {
        return;
    }
    // 遍历Excel文件中每一行数据，将每一行数据映射为Java对象并添加到dataList中
    for (int i = readSheet.getHead().getRowIndex(); i < rows.size(); i++) {
        List<String> row = rows.get(i);
        T data = ReflectionUtil.newInstance(currentSheetClazz);
        for (int j = 0; j < fieldList.size(); j++) {
            Field field = fieldList.get(j);
            ExcelProperty excelProperty = field.getAnnotation(ExcelProperty.class);
            int index = excelProperty.index();
            if (index >= row.size()) {
                continue;
            }
            String value = row.get(index);
            ReflectionUtil.setFieldValue(field, data, value);
        }
        dataList.add(data);
    }
    // 将读取到的数据返回给调用方
    readSheet.getResultList().addAll(dataList);
}

private List<List<String>> sheet2List() {
    // 从Sheet中获取所有行
    int rownum = sheet.getLastRowNum();
    List<List<String>> rows = new ArrayList<>(rownum);
    for (int i = sheet.getFirstRowNum(); i <= rownum; i++) {
        Row row = sheet.getRow(i);
        if (null == row) {
            continue;
        }
        List<String> cells = new ArrayList<>(row.getLastCellNum());
        for (int j = row.getFirstCellNum(); j < row.getLastCellNum(); j++) {
            Cell cell = row.getCell(j, Row.MissingCellPolicy.CREATE_NULL_AS_BLANK);
            String cellValue = ExcelUtil.getCellValue(cell);
            cells.add(cellValue);
        }
        rows.add(cells);
    }
    return rows;
}

public class ExcelWriter extends AbstractExcelWriter<WriteSheet> {
    // 省略部分代码及构造方法
}

public void write(List data, WriteSheet sheet) {
    sheetHolder.set(sheet);
    if (sheet == null) {
        return;
    }
    sheet.init();
    int index = sheetHolder.get().getIndex() == null ? 0 : sheetHolder.get().getIndex();
    String sheetName = sheetHolder.get().getSheetName() == null ? "Sheet" + index : sheetHolder.get().getSheetName();
    currentSheet = workbook.createSheet(sheetName);
    write(data);
    sheetHolder.remove();
}

private void write(List data) {
    WriteHandler handler = sheetHolder.get().getWriteHandler();
    if (handler != null && handler instanceof WorkbookHolder) {
        ((WorkbookHolder) handler).setWorkbook(workbook);
    }
    // 获取Java对象中用于映射Excel中数据的属性列表
    List<Field> fieldList = ReflectionUtil.getFieldListWithExcelColumn(data.get(0).getClass());
    // 设置Excel文件中的表头
    setHead(handler, fieldList);
    try {
        // 遍历Java对象并将其写入到Excel文件中
        for (int i = 0; i < data.size(); i++) {
            Object rowModel = data.get(i);
            setIndexValue(i + 1);
            Row row = currentSheet.createRow(getRowIndex());
            for (int j = 0; j < fieldList.size(); j++) {
                Field field = fieldList.get(j);
                if (needIgnore(j)) {
                    continue;
                }
                String stringValue = ReflectionUtil.getFieldStringValue(field, rowModel);
                Cell cell = row.createCell(j);
                if (handler != null && handler instanceof AbstractCellStyleStrategy) {
                    ((AbstractCellStyleStrategy) handler).setCellStyle(cell, field, rowModel, getStringValue(stringValue));
                }
                CellData cellData = converterAndSet(cell, stringValue, field);
                setCellComment(row, field, cellData);
            }
        }
    } finally {
        setIndexValue(null);
    }
}