实体类

@Data
public class Student {

    @ExcelProperty(value = "学生姓名")
    private String name;

    @ExcelProperty(value = "年龄")
    private Integer age;

    @ExcelProperty(value = "出生日期")
    private String bornDate;

}

controller层

@PostMapping("/getListExcel")
    @ApiOperation("导出excel")
    public String getCameraListExcel(@RequestBody List<Student> student)
    {
        String fileName = "测试excel2"+".xlsx";
        //指定path路径
        String excelFileName = CommonConstant.PATH +fileName;
        EasyExcel.write(excelFileName,Student.class).head(Student.class).sheet("学生表")
                //自适应列宽
                .registerWriteHandler(new CustomCellWriteHandler())
                //时间转换器
                .registerConverter(new LocalDateConverter()).doWrite(student);
        return excelFileName;
    }

自适应列宽处理类

import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.util.CollectionUtils;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.Cell;

import java.util.HashMap;
import java.util.List;
import java.util.Map;


/**
 * 自适应列宽
 */
@Slf4j
public class CustomCellWriteHandler extends AbstractColumnWidthStyleStrategy {

    public final static Integer COLUMN_WIDTH = 255;

    private Map<Integer, Map<Integer, Integer>> cache = new HashMap<>();

    @Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
        if (needSetWidth) {
            Map<Integer, Integer> maxColumnWidthMap = cache.get(writeSheetHolder.getSheetNo());
            if (maxColumnWidthMap == null) {
                maxColumnWidthMap = new HashMap<>(16);
                cache.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
            }

            Integer columnWidth = this.dataLength(cellDataList, cell, isHead);
            if (columnWidth >= 0) {
                if (columnWidth > COLUMN_WIDTH) {
                    columnWidth = 255;
                }

                Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());
                if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
                    maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);
                    writeSheetHolder.getSheet().setColumnWidth(cell.getColumnIndex(), columnWidth * 256);
                }

            }
        }
    }

    private Integer dataLength(List<CellData> cellDataList, Cell cell, Boolean isHead) {
        if (isHead) {
            return cell.getStringCellValue().getBytes().length;
        } else {
            CellData cellData = cellDataList.get(0);
            CellDataTypeEnum type = cellData.getType();
            if (type == null) {
                return -1;
            } else {
                switch (type) {
                    case STRING:
                        return cellData.getStringValue().getBytes().length;
                    case BOOLEAN:
                        return cellData.getBooleanValue().toString().getBytes().length;
                    case NUMBER:
                        return cellData.getNumberValue().toString().getBytes().length;
                    default:
                        return -1;
                }
            }
        }
    }
}

时间转换器

import com.alibaba.excel.converters.Converter;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.GlobalConfiguration;
import com.alibaba.excel.metadata.property.ExcelContentProperty;
import org.springframework.stereotype.Component;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

/**
 * 导出excel时，时间格式为LocalDate的转换器工具
 */
@Component
public class LocalDateConverter implements Converter<LocalDate> {

    @Override
    public Class<LocalDate> supportJavaTypeKey() {
        return LocalDate.class;
    }

    @Override
    public CellDataTypeEnum supportExcelTypeKey() {
        return CellDataTypeEnum.STRING;
    }

    @Override
    public LocalDate convertToJavaData(CellData cellData, ExcelContentProperty excelContentProperty, GlobalConfiguration globalConfiguration) throws Exception {
        return LocalDate.parse(cellData.getStringValue(), DateTimeFormatter.ofPattern("yyyy-MM-dd"));
    }

    @Override
    public CellData<String> convertToExcelData(LocalDate localDate, ExcelContentProperty excelContentProperty, GlobalConfiguration globalConfiguration) throws Exception {
        return new CellData<>(localDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
    }
}