<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>3.3.2</version> <!-- 使用最新版本 -->
</dependency>

// 主表數(shù)據(jù)
public class Order {
    private String orderNo;
    private Date orderDate;
    private String customerName;
    private List<OrderItem> items;
    
    // getters and setters
}

// 子表數(shù)據(jù)
public class OrderItem {
    private String productName;
    private Integer quantity;
    private BigDecimal price;
    private BigDecimal amount;
    
    // getters and setters
}

public class OrderExcelExport {
    public static void exportOrders(List<Order> orders, HttpServletResponse response) throws IOException {
        String fileName = "訂單報(bào)表_" + System.currentTimeMillis() + ".xlsx";
        
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
        
        ExcelWriter excelWriter = EasyExcel.write(response.getOutputStream()).build();
        
        // 主表sheet
        WriteSheet mainSheet = EasyExcel.writerSheet(0, "訂單信息")
                .head(Order.class)
                .build();
        
        // 子表sheet
        WriteSheet itemSheet = EasyExcel.writerSheet(1, "訂單明細(xì)")
                .head(OrderItem.class)
                .build();
        
        // 寫入主表數(shù)據(jù)
        excelWriter.write(orders, mainSheet);
        
        // 寫入子表數(shù)據(jù)
        for (Order order : orders) {
            excelWriter.write(order.getItems(), itemSheet);
        }
        
        excelWriter.finish();
    }
}

public class OrderExcelExport {
    public static void exportOrdersInOneSheet(List<Order> orders, HttpServletResponse response) throws IOException {
        String fileName = "訂單報(bào)表_" + System.currentTimeMillis() + ".xlsx";
        
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
        
        // 自定義合并策略
        HorizontalCellStyleStrategy styleStrategy = new HorizontalCellStyleStrategy();
        
        ExcelWriter excelWriter = EasyExcel.write(response.getOutputStream())
                .registerWriteHandler(new OrderMergeStrategy(orders))
                .registerWriteHandler(styleStrategy)
                .build();
        
        WriteSheet sheet = EasyExcel.writerSheet("訂單及明細(xì)")
                .head(OrderExcelData.class)
                .build();
        
        // 轉(zhuǎn)換數(shù)據(jù)
        List<OrderExcelData> dataList = convertToExcelData(orders);
        excelWriter.write(dataList, sheet);
        
        excelWriter.finish();
    }
    
    private static List<OrderExcelData> convertToExcelData(List<Order> orders) {
        List<OrderExcelData> result = new ArrayList<>();
        for (Order order : orders) {
            boolean isFirstItem = true;
            for (OrderItem item : order.getItems()) {
                OrderExcelData data = new OrderExcelData();
                if (isFirstItem) {
                    data.setOrderNo(order.getOrderNo());
                    data.setOrderDate(order.getOrderDate());
                    data.setCustomerName(order.getCustomerName());
                    isFirstItem = false;
                }
                data.setProductName(item.getProductName());
                data.setQuantity(item.getQuantity());
                data.setPrice(item.getPrice());
                data.setAmount(item.getAmount());
                result.add(data);
            }
        }
        return result;
    }
}

// 合并策略
public class OrderMergeStrategy implements CellWriteHandler {
    private List<Order> orders;
    private int itemCount = 0;
    
    public OrderMergeStrategy(List<Order> orders) {
        this.orders = orders;
        for (Order order : orders) {
            itemCount += order.getItems().size();
        }
    }
    
    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, 
            List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        // 合并主表信息單元格
        if (cell.getRowIndex() == 1 && !isHead) {
            for (int i = 0; i < orders.size(); i++) {
                Order order = orders.get(i);
                int itemSize = order.getItems().size();
                if (itemSize > 1) {
                    // 合并訂單號、日期、客戶名等主表信息
                    if (cell.getColumnIndex() == 0) { // 訂單號
                        writeSheetHolder.getSheet().addMergedRegionUnsafe(
                            new CellRangeAddress(cell.getRowIndex(), cell.getRowIndex() + itemSize - 1, 0, 0));
                    } else if (cell.getColumnIndex() == 1) { // 訂單日期
                        writeSheetHolder.getSheet().addMergedRegionUnsafe(
                            new CellRangeAddress(cell.getRowIndex(), cell.getRowIndex() + itemSize - 1, 1, 1));
                    } else if (cell.getColumnIndex() == 2) { // 客戶名
                        writeSheetHolder.getSheet().addMergedRegionUnsafe(
                            new CellRangeAddress(cell.getRowIndex(), cell.getRowIndex() + itemSize - 1, 2, 2));
                    }
                }
            }
        }
    }
}

// Excel數(shù)據(jù)模型
public class OrderExcelData {
    @ExcelProperty("訂單編號")
    private String orderNo;
    
    @ExcelProperty("訂單日期")
    @DateTimeFormat("yyyy-MM-dd")
    private Date orderDate;
    
    @ExcelProperty("客戶名稱")
    private String customerName;
    
    @ExcelProperty("產(chǎn)品名稱")
    private String productName;
    
    @ExcelProperty("數(shù)量")
    private Integer quantity;
    
    @ExcelProperty("單價")
    private BigDecimal price;
    
    @ExcelProperty("金額")
    private BigDecimal amount;
    
    // getters and setters
}

@RestController
@RequestMapping("/api/order")
public class OrderController {
    
    @GetMapping("/export")
    public void exportOrders(HttpServletResponse response) throws IOException {
        // 模擬數(shù)據(jù)
        List<Order> orders = getMockOrders();
        
        // 導(dǎo)出Excel
        OrderExcelExport.exportOrdersInOneSheet(orders, response);
    }
    
    private List<Order> getMockOrders() {
        List<Order> orders = new ArrayList<>();
        
        // 訂單1
        Order order1 = new Order();
        order1.setOrderNo("ORD20230001");
        order1.setOrderDate(new Date());
        order1.setCustomerName("客戶A");
        
        List<OrderItem> items1 = new ArrayList<>();
        OrderItem item1 = new OrderItem();
        item1.setProductName("產(chǎn)品A");
        item1.setQuantity(2);
        item1.setPrice(new BigDecimal("100.00"));
        item1.setAmount(new BigDecimal("200.00"));
        items1.add(item1);
        
        OrderItem item2 = new OrderItem();
        item2.setProductName("產(chǎn)品B");
        item2.setQuantity(1);
        item2.setPrice(new BigDecimal("50.00"));
        item2.setAmount(new BigDecimal("50.00"));
        items1.add(item2);
        
        order1.setItems(items1);
        orders.add(order1);
        
        // 訂單2
        Order order2 = new Order();
        order2.setOrderNo("ORD20230002");
        order2.setOrderDate(new Date());
        order2.setCustomerName("客戶B");
        
        List<OrderItem> items2 = new ArrayList<>();
        OrderItem item3 = new OrderItem();
        item3.setProductName("產(chǎn)品C");
        item3.setQuantity(3);
        item3.setPrice(new BigDecimal("30.00"));
        item3.setAmount(new BigDecimal("90.00"));
        items2.add(item3);
        
        order2.setItems(items2);
        orders.add(order2);
        
        return orders;
    }
}

// 自定義樣式策略
public class CustomCellStyleStrategy implements CellWriteHandler {
    @Override
    public void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, 
            Row row, Head head, Integer columnIndex, Integer relativeRowIndex, Boolean isHead) {
    }
    
    @Override
    public void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, 
            Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        Workbook workbook = writeSheetHolder.getSheet().getWorkbook();
        
        // 標(biāo)題樣式
        if (isHead) {
            CellStyle cellStyle = workbook.createCellStyle();
            Font font = workbook.createFont();
            font.setBold(true);
            font.setColor(IndexedColors.WHITE.getIndex());
            cellStyle.setFont(font);
            cellStyle.setFillForegroundColor(IndexedColors.BLUE.getIndex());
            cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
            cellStyle.setAlignment(HorizontalAlignment.CENTER);
            cell.setCellStyle(cellStyle);
        }
        
        // 數(shù)據(jù)行樣式
        else {
            CellStyle cellStyle = workbook.createCellStyle();
            cellStyle.setBorderTop(BorderStyle.THIN);
            cellStyle.setBorderBottom(BorderStyle.THIN);
            cellStyle.setBorderLeft(BorderStyle.THIN);
            cellStyle.setBorderRight(BorderStyle.THIN);
            
            // 金額列右對齊
            if (cell.getColumnIndex() >= 5) {
                cellStyle.setAlignment(HorizontalAlignment.RIGHT);
            }
            
            cell.setCellStyle(cellStyle);
        }
    }
    
    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, 
            List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
    }
}

ExcelWriter excelWriter = EasyExcel.write(response.getOutputStream())
        .registerWriteHandler(new OrderMergeStrategy(orders))
        .registerWriteHandler(new CustomCellStyleStrategy())
        .build();