java的excel导出hashmap数据

以下是Java中使用EasyExcel库导出HashMap数据到Excel的示例代码：

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.write.metadata.WriteSheet;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ExcelExportUtil {

    public static void exportExcel(List<Map<String, Object>> dataList, String fileName, String sheetName) throws IOException {
        // 构造ExcelWriter对象
        ExcelWriter excelWriter = EasyExcel.write(fileName).build();

        // 构造WriteSheet对象
        WriteSheet writeSheet = EasyExcel.writerSheet(sheetName).build();

        // 构造表头
        List<String> headList = new ArrayList<>();
        for (String key : dataList.get(0).keySet()) {
            headList.add(key);
        }

        // 写入表头
        excelWriter.writeHead(headList, writeSheet);

        // 写入数据
        List<List<Object>> dataList2 = new ArrayList<>();
        for (Map<String, Object> data : dataList) {
            List<Object> rowList = new ArrayList<>();
            for (String key : headList) {
                rowList.add(data.get(key));
            }
            dataList2.add(rowList);
        }
        excelWriter.write(dataList2, writeSheet);

        // 关闭ExcelWriter对象
        excelWriter.finish();
    }

    public static void main(String[] args) throws IOException {
        // 构造测试数据
        List<Map<String, Object>> dataList = new ArrayList<>();
        for (int i = 1; i <= 10; i++) {
            Map<String, Object> data = new HashMap<>();
            data.put("id", i);
            data.put("name", "name" + i);
            data.put("age", 20 + i);
            dataList.add(data);
        }

        // 导出Excel
        exportExcel(dataList, "test.xlsx", "Sheet1");
    }
}

以上代码中，我们使用EasyExcel库来实现Excel的导出。首先，我们构造ExcelWriter对象和WriteSheet对象，然后构造表头，写入表头，最后写入数据即可。需要注意的是，EasyExcel库要求数据必须是List<List<Object>>类型，因此我们需要将HashMap数据转换为这种类型。另外，如果HashMap中有Date类型的字段，需要将其转换为String类型，否则会报错。