easyexcel动态下拉框，动态表头

private static final int FLAG1 = 1;
private static final int FLAG2 = 2;
private static final int FLAG3 = 3;

/**
 * 动态列头
 *
 * @return
 */
private List<List<String>> head(Integer headFlag) {
    List<User> userList = new ArrayList<>();
    int size = userList.size();
    String fields[] = new String[size];
    for (int i = 0; i < userList.size(); i++) {
        String name = userList.get(i).getName();
        fields[i] = name;
    }
    List<String> strings = Arrays.asList(fields);
    ArrayList<String> heads = new ArrayList<>();
    heads.addAll(strings);
    //不同头标记额外不同的列头
    switch (headFlag) {
        case 1:
            heads.add("xxxx");
            break;
        case 2:
            heads.add("xxxx");
            break;
        case 3:
            heads.add("xxxx");
            break;
    }
    List<List<String>> headList = new ArrayList<List<String>>();
    int length = heads.size();
    for (int i = 0; i < length; i++) {
        List<String> list = new ArrayList<>();
        list.add(heads.get(i));
        headList.add(list);
    }
    return headList;
}

/**
 * 动态猎头要写出的数据
 *
 * @param users
 * @param headFlag   FLAG1  FLAG2  FLAG3
 * @return
 */
private List<List<Object>> dataList(List<User> users, Integer headFlag) {
    List<List<Object>> list = new ArrayList<List<Object>>();
    if (!ObjectUtils.isEmpty(users)) {
        users.forEach(archive -> {
            List<Object> data = new ArrayList<Object>();
            data.add(archive.getAge());
            //不同类型的表头要写的数据
            if (FLAG1 == headFlag) {
                data.add("xxxxxx");
            }

            if (FLAG2 == headFlag) {
                data.add("xxxxxx");
            }

            if (FLAG3 == headFlag) {
                data.add("xxxxxx");
            }
            list.add(data);
        });
    }
    return list;
}

/**
 * 实际写出的数据
 * key:  FLAG1  FLAG2  FLAG3
 * value:  对应的数据
 */
public void handelExcelWriteData() {
    //实际要写出的数据
    List<User> waitUserList = new ArrayList<>();
    List<User> userDateList = new ArrayList<>();
    List<User> noUserList = new ArrayList<>();

    Map<List<List<String>>, List<User>> hashMap1 = new HashMap<>();
    Map<List<List<String>>, List<User>> hashMap2 = new HashMap<>();
    Map<List<List<String>>, List<User>> hashMap3 = new HashMap<>();

    List<List<String>> head1 = head(FLAG1);
    hashMap1.put(head1, waitUserList);

    List<List<String>> head2 = head(FLAG2);
    hashMap2.put(head2, userDateList);

    List<List<String>> head3 = head(FLAG3);
    hashMap3.put(head3, noUserList);

    Map<Integer, Map<List<List<String>>, List<User>>> dataListMap = new HashMap();
    //不同类型对应的数据
    dataListMap.put(FLAG1, hashMap1);
    dataListMap.put(FLAG2, hashMap2);
    dataListMap.put(FLAG3, hashMap3);
    this.handelExcelData(dataListMap);
}


/**
 * 处理excel数据
 * @param dataListMap
 */
private void handelExcelData(Map<Integer, Map<List<List<String>>, List<User>>> dataListMap) {
    String path = "实际要导出的路径";
    try {
        File parentFile = new File(path);
        if (!parentFile.exists()) {
            parentFile.mkdirs();
            parentFile.createNewFile();
        }
        String[] split0 = new String[0];//选择下拉框 TODO 根据实际情况去做下列数据
        String[] split1 = new String[0];//选择下拉框 TODO  根据实际情况去做下列数据


        ExcelWriter excelWriter = EasyExcel.write(path).build();
        Iterator<Map.Entry<Integer, Map<List<List<String>>, List<User>>>> iterator = dataListMap.entrySet().iterator();
        while (iterator.hasNext()) {
            Map.Entry<Integer, Map<List<List<String>>, List<User>>> next = iterator.next();
            //key  FLAG1 FLAG2 FLAG3
            Integer key = next.getKey();
            if (key == FLAG1) {
                this.writeExcel(next, FLAG1, excelWriter, split0, split1);
            } else if (key == FLAG2) {
                this.writeExcel(next, FLAG2, excelWriter, split0, split1);
            } else if (key == FLAG3) {
                this.writeExcel(next, FLAG3, excelWriter, split0, split1);
            }
        }
        excelWriter.finish();

    } catch (Exception e) {
        //异常写出空文件
        ExcelWriter excelWriter = EasyExcel.write(path).build();
        WriteSheet writeSheet = EasyExcel.writerSheet(0).sheetName("sheet" + 0)
                .build();
        excelWriter.write(new ArrayList<>(), writeSheet);
        excelWriter.finish();

    }
}

/**
 *
 * @param next  实际数据
 * @param controlHeadFlag
 * @param excelWriter
 * @param split0
 * @param split1
 */
private void writeExcel(Map.Entry<Integer, Map<List<List<String>>, List<User>>> next,
                        Integer controlHeadFlag, ExcelWriter excelWriter, String[] split0,
                        String[] split1) {
    Map<List<List<String>>, List<User>> value = next.getValue();
    Iterator<Map.Entry<List<List<String>>, List<User>>> iterator1 = value.entrySet().iterator();
    //里面只有一个
    while (iterator1.hasNext()) {
        Map.Entry<List<List<String>>, List<User>> next1 = iterator1.next();
        //动态要写出的数据
        List<User> value1 = next1.getValue();
        if (!CollectionUtils.isEmpty(value1)) {
            //行号（有多少数据就有多少行）
            int row = value1.size();
            //动态列头
            List<List<String>> key1 = next1.getKey();
            //列号（其实就是下拉框在第几列）
            int raw = key1.size();
            List<List<Object>> lists = this.dataList(value1, controlHeadFlag);
            WriteSheet writeSheet = EasyExcel.writerSheet(controlHeadFlag - 1).sheetName("sheet" + controlHeadFlag)
                    .head(key1)
                    .registerWriteHandler(new SpinnerWriteHandler(split0, split1, row, raw))
                    .build();
            excelWriter.write(lists, writeSheet);
        }
    }
}

/**
 * 下拉监听
 * 动态下拉框输出处理
 */
@Slf4j
public class SpinnerWriteHandler implements SheetWriteHandler {


    //     下拉框数组
    private String[] split0;

    //     下拉框数组
    private String[] split1;
    //行
    private Integer row;
    //列
    private Integer raw;

    Map<Integer, String> staticMap = new HashMap();

    {
        staticMap.put(1, "XXXXXX");//新建的sheet用于存放下拉框内的数据,
        staticMap.put(2, "XXXXXX");
    }


    public SpinnerWriteHandler(String[] split0, String[] split1, Integer row, Integer raw) {
        this.split0 = split0;
        this.split1 = split1;
        this.row = row;
        this.raw = raw;
    }

    @Override
    public void beforeSheetCreate(WriteWorkbookHolder writeWorkbookHolder, WriteSheetHolder writeSheetHolder) {
    }

    @Override
    public void afterSheetCreate(WriteWorkbookHolder writeWorkbookHolder, WriteSheetHolder writeSheetHolder) {
//        //设置下拉框数据
        Map<Integer, String[]> map = new HashMap<>();
        //这里时两列相邻的下拉框
        map.put(raw - 1, this.split0); //动态列号
        map.put(raw - 2, this.split1);//动态列号
        //动态解决单个单元格下拉框超过255字符
        log.info("第{}个Sheet写入成功。", writeSheetHolder.getSheetNo());
        DataValidationHelper helper = writeSheetHolder.getSheet().getDataValidationHelper();

        int flag = 0;
        // 省市下拉框
        for (Map.Entry<Integer, String[]> entry : map.entrySet()) {
            ++flag;
            // 创建sheet，突破下拉框255的限制
            //获取一个workbook
            Workbook workbook = writeWorkbookHolder.getWorkbook();
            //定义sheet的名称
            String sheetName = staticMap.get(flag);
            //1.创建一个隐藏的sheet
            Name name = workbook.getName(sheetName);
            String[] value = entry.getValue();
            if (!ObjectUtils.isEmpty(value)) {
                if (ObjectUtils.isEmpty(name)) {
                    Sheet sheet = workbook.createSheet(sheetName);
                    Name category1Name = workbook.createName();
                    category1Name.setNameName(sheetName);
                    int length1 = entry.getValue().length;
                    for (int i = 0, length = length1; i < length; i++) {
                        // i:表示你开始的行数  0表示你开始的列数
                        sheet.createRow(i).createCell(0).setCellValue(value[i]);
                    }
                    if (!ObjectUtils.isEmpty(value)) {
                        //从被创建的sheet第一个单元格开始向下填充  填充到实际数据长度【value.length的行号】
                        category1Name.setRefersToFormula(sheetName + "!$A$1:$A$" + (value.length));
                        // sheet设置隐藏
                        workbook.setSheetHidden(workbook.getSheetIndex(sheetName), true);
                    }

                } else {
                    Name category1Name = workbook.getName(sheetName);
                    Sheet sheet1 = workbook.getSheet(sheetName);
                    int length1 = entry.getValue().length;
                    for (int i = 0, length = length1; i < length; i++) {
                        // i:表示你开始的行数  0表示你开始的列数
                        sheet1.createRow(i).createCell(0).setCellValue(value[i]);
                    }
                    if (!ObjectUtils.isEmpty(value)) {
                        category1Name.setRefersToFormula(sheetName + "!$A$1:$A$" + (value.length));
                    }
                }

                                                                                    //从第一行填充至row行（包含），第 entry.getKey() 列至entry.getKey()列【因为只填充一个单元格,所以起始一致】
                CellRangeAddressList addressList = new CellRangeAddressList(1, row, entry.getKey(), entry.getKey());
                DataValidationConstraint constraint8 = helper.createFormulaListConstraint(sheetName);
                DataValidation dataValidation3 = helper.createValidation(constraint8, addressList);
                writeSheetHolder.getSheet().addValidationData(dataValidation3);
                //处理Excel兼容性问题
                if (dataValidation3 instanceof XSSFDataValidation) {
                    dataValidation3.setSuppressDropDownArrow(true);
                    dataValidation3.setShowErrorBox(true);
                } else {
                    dataValidation3.setSuppressDropDownArrow(false);
                }
                Sheet sheet0 = writeSheetHolder.getSheet();
                //5 将刚才设置的sheet引用到你的下拉列表中
                sheet0.addValidationData(dataValidation3);
            }

        }
    }
}