springboot使用easyExcel导出Excel表格以及LocalDateTime时间类型转换问题

以下内容仅供学习使用

1. 首先引入pom.xml依赖

     <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.7.20</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>4.1.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>3.2.1</version>
        </dependency>

2. 实体类

import com.alibaba.excel.annotation.ExcelProperty;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import com.el.springboot.config.LocalDateTimeConverter;
import com.fasterxml.jackson.annotation.JsonFormat;

import lombok.Getter;
import lombok.Setter;

import java.io.Serializable;
import java.time.LocalDateTime;

/**
 * <p>
 *
 * </p>
 *
 * @author el
 * @since 2023-03-19
 */
@Getter
@Setter
@TableName("sys_user")
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;

    /**
     * 用户名
     */
    private String username;

    /**
     * 密码
     */
    private String password;

    /**
     * 昵称
     */
    private String nickname;

    /**
     * 邮箱
     */
    private String email;

    /**
     * 号码
     */
    private String phone;

    /**
     * 地址
     */
    private String address;

    /**
     * 创建时间
     */
    @ExcelProperty(value = "创建时间", converter = LocalDateTimeConverter.class)
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    //@ExcelIgnore
    private LocalDateTime createTime;

    /**
     * 头像
     */
    private String avatarUrl;
}

3. controller类使用

/**
     * 导出接口
     */
    @GetMapping("/export")
    public void export(HttpServletResponse response) throws Exception {
        // 从数据库查询出所有的数据
        List<User> list = userService.list();
        // 通过工具类创建writer 写出到磁盘路径
//        ExcelWriter writer = ExcelUtil.getWriter(filesUploadPath + "/用户信息.xlsx");
        // 在内存操作，写出到浏览器
        ExcelWriter writer = ExcelUtil.getWriter(true);
        //自定义标题别名
        writer.addHeaderAlias("username", "用户名");
        writer.addHeaderAlias("password", "密码");
        writer.addHeaderAlias("nickname", "昵称");
        writer.addHeaderAlias("email", "邮箱");
        writer.addHeaderAlias("phone", "电话");
        writer.addHeaderAlias("address", "地址");
        writer.addHeaderAlias("createTime", "创建时间");
        writer.addHeaderAlias("avatarUrl", "头像");

        // 一次性写出list内的对象到excel，使用默认样式，强制输出标题
        writer.write(list,true);

        // 设置浏览器响应的格式
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
        String fileName = URLEncoder.encode("用户信息", "UTF-8");
        response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".xlsx");

        ServletOutputStream out = response.getOutputStream();
        writer.flush(out, true);
        out.close();
        writer.close();

    }

4. 注意事项!（很重要！！！）

因为easyExcel不支持LocalDateTime的时间类型格式

所以需要自己新建一个config配置然后新建LocalDateTimeConverter类

import com.alibaba.excel.converters.Converter;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.GlobalConfiguration;
import com.alibaba.excel.metadata.data.ReadCellData;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.metadata.property.ExcelContentProperty;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class LocalDateTimeConverter implements Converter<LocalDateTime> {

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

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

    @Override
    public LocalDateTime convertToJavaData(ReadCellData cellData, ExcelContentProperty contentProperty,
                                           GlobalConfiguration globalConfiguration) {
        return LocalDateTime.parse(cellData.getStringValue(), DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    }


    @Override
    public WriteCellData<String> convertToExcelData(LocalDateTime value, ExcelContentProperty contentProperty,
                                                    GlobalConfiguration globalConfiguration) {
        return new WriteCellData(value.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
    }


}

5. 最后就是在实体类哪里看到的最后效果

    /**
     * 创建时间
     */
    @ExcelProperty(value = "创建时间", converter = LocalDateTimeConverter.class)
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    //@ExcelIgnore
    private LocalDateTime createTime;

6. 效果

6.1 postman测试接口

6.2 建议点击下面这个，这样子就可以自动生成一个Excel表格了！

6.3 或者浏览器直接输入地址默认自己下载

7. 最终效果图