动态导出分为三种：

1. 动态指定标题、字段顺序；
2. 字段分组；
3. Map导出；

1.动态指定标题、字段顺序

// title
List<String> titles = new ArrayList<>();
titles.add("姓名");
titles.add("年龄");
// field display order
List<String> order = new ArrayList<>();
order.add("name");
order.add("age");
// display data
List<TestDO> dataList = this.getData();
Workbook workbook = DefaultExcelBuilder.of(TestDO.class)
                                    .sheetName("default example")
                                    .titles(titles)
                                    .fieldDisplayOrder(order)
                                    .build(dataList);
private List<TestDO> getData(){
  TestDO testDO = new TestDO();
  testDO.setName("张三");
  TestDO testDO1 = new TestDO();
  testDO1.setName("李四");
  TestDO testDO2 = new TestDO();
  testDO2.setName("王五");
  testDO2.setAge(15);
  TestDO testDO3 = new TestDO();
  testDO3.setName("陈六");
  testDO3.setAge(25);
  List<TestDO> dataList = new ArrayList<>();
  dataList.add(testDO);
  dataList.add(testDO1);
  dataList.add(testDO2);
  dataList.add(testDO3);
  return dataList;
}

2.字段分组

该种方式基于注解@ExcelColumn的groups属性

@ExcelColumn(title="姓名",groups={People.class})
String name;
@ExcelColumn(title="年龄")
String age;
DefaultExcelBuilder.of(ArtCrowd.class).build(People.class);

上述示例将只导出姓名字段

3.Map导出

Map<String, String> headerMap = new HashMap<>();
headerMap.put("a", "测试A");
headerMap.put("b", "测试B");
List<Map> dataMapList = new ArrayList<>();
Map<String, Object> v1 = new HashMap<>();
v1.put("a", "数据a1");
v1.put("b", 3);
Map<String, Object> v2 = new HashMap<>();
v2.put("a", "数据a2");
v2.put("b", 5);
dataMapList.add(v1);
dataMapList.add(v2);
List<String> titles = new ArrayList(headerMap.values());
List<String> orders = new ArrayList(headerMap.keySet());
Workbook workbook = DefaultExcelBuilder.of(Map.class)
        .sheetName("sheet1")
        .titles(titles)
        .widths(10,20)
        .fieldDisplayOrder(orders)
        .build(dataMapList);
FileExportUtil.export(workbook, new File("/tmp/zz.xlsx"));

Map导出默认不支持格式化，需自行格式化，如需指定Map中value类型，如超链接等，value需设置如下：

import com.github.liaochong.myexcel.core.constant.LinkUrl;
import com.github.liaochong.myexcel.core.container.Pair;
Map<String, Object> obj = new HashMap<>();
obj.put("2", Pair.of(LinkUrl.class,"http://www.baidu.com"));