SpringBoot 集成 EasyExcel 3.x 实现 Excel 导出

EasyExcel官方文档

EasyExcel是什么？

EasyExcel注解

springboot集成EasyExcel

简单入门导出：

实体类

自定义转换类

测试一下

复杂表头一对多导出：

自定义注解

定义实体类

自定义单元格合并策略

测试一下

EasyExcel官方文档

EasyExcel官方文档 - 基于Java的Excel处理工具 | Easy Excel

EasyExcel是什么？

EasyExcel是一个基于Java的、快速、简洁、解决大文件内存溢出的Excel处理工具.他能让你在不用考虑性能、内存的等因素的情况下，快速完成Excel的读、写等功能。

EasyExcel注解

@ExcelProperty: 核心注解，value属性可用来设置表头名称，converter属性可以用来设置类型转换器
@ColumnWidth: 用于设置表格列的宽度
@DateTimeFormat: 用于设置日期转换格式
@NumberFormat: 用于设置数字转换格式
@ExcelIgnore：默认所有字段都会和excel去匹配，加了这个注解会忽略该字段
@ExcelIgnoreUnannotated：默认不加 ExcelProperty 的注解的都会参与读写，加了不会参与读写

具体使用请参考：

读Excel：读Excel | Easy Excel

写Excel：写Excel | Easy Excel

springboot集成EasyExcel

springboot集成EasyExcel3.x非常简单，只需要引入以下依赖即可。

<dependency><groupId>com.alibaba</groupId><artifactId>easyexcel</artifactId><version>3.1.3</version>
</dependency>

简单入门导出：

接下来使用EasyExcel实现简单导出功能。

实体类

导入数据还是导出数据都可以想象成具体某个对象的集合。

@Data
public class StudentDo {@ExcelProperty("用户编号")@ColumnWidth(20)private Long id;@ExcelProperty("用户名")@ColumnWidth(20)private String studentName;@ExcelIgnoreprivate String password;@ExcelProperty("生日")@ColumnWidth(20)@DateTimeFormat("yyyy-MM-dd")private Date birthday;@ExcelProperty("身高（米）")@NumberFormat("#.##")@ColumnWidth(20)private Double height;@ExcelProperty(value = "性别", converter = GenderConverter.class)@ColumnWidth(10)private Integer gender;
}

自定义转换类

导出excel数据时，可能会遇到XXX状态、XXX类型和性别等需要转换的字段，例如：0->男，1->女。需实现Converter接口来自定义转换器。

orElse(null)与orElseGet(null)区别：

orElse(null)表示如果一个都没找到返回null。【orElse()中可以塞默认值。如果找不到就会返回orElse中你自己设置的默认值。】

orElseGet(null)表示如果一个都没找到返回null。【orElseGet()中可以塞默认值。如果找不到就会返回orElseGet中你自己设置的默认值。】

区别就是在使用方法时，即时时没有值也会执行 orElse 内的方法，而 orElseGet则不会。

Enum：

@Getter
@AllArgsConstructor
public enum GenderEnum {/*** 男性*/MALE(0, "男性"),/*** 女性*/FEMALE(1, "女性"),/*** 未知*/UNKNOWN(2, "未知");private final Integer value;@JsonFormatprivate final String description;public static GenderEnum convert(Integer value) {return Stream.of(values()).filter(bean -> bean.value.equals(value)).findAny().orElse(UNKNOWN);}public static GenderEnum convert(String description) {return Stream.of(values()).filter(bean -> bean.description.equals(description)).findAny().orElse(UNKNOWN);}
}

Converter：

public class GenderConverter implements Converter<Integer> {@Overridepublic Class<?> supportJavaTypeKey() {return Integer.class;}@Overridepublic CellDataTypeEnum supportExcelTypeKey() {return CellDataTypeEnum.STRING;}@Overridepublic Integer convertToJavaData(ReadConverterContext<?> context) {return GenderEnum.convert(context.getReadCellData().getStringValue()).getValue();}@Overridepublic WriteCellData<?> convertToExcelData(WriteConverterContext<Integer> context) {return new WriteCellData<>(GenderEnum.convert(context.getValue()).getDescription());}
}

测试一下

File.separator等价于“\”

package com.springwork.high.easyexcel.controller;/*** @author gj* @version 1.0.0* @date 2023/7/7 15:36*/import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.support.ExcelTypeEnum;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.springwork.high.easyexcel.vo.StudentDo;
import com.sun.deploy.net.URLEncoder;
import org.springframework.core.io.ClassPathResource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.List;/*** EasyExcel导入导出** @author william@StarImmortal*/
@RestController
@RequestMapping("/excel")
public class ExcelController {@GetMapping("/export/student")public void exportUserExcel(HttpServletResponse response) {try {this.setExcelResponseProp(response, "学生列表");List<StudentDo> studentList = this.getStudentList();EasyExcel.write(response.getOutputStream()).head(StudentDo.class).excelType(ExcelTypeEnum.XLSX).sheet("学生列表").doWrite(studentList);} catch (IOException e) {throw new RuntimeException(e);}}/*** 设置响应结果** @param response    响应结果对象* @param rawFileName 文件名* @throws UnsupportedEncodingException 不支持编码异常*/private void setExcelResponseProp(HttpServletResponse response, String rawFileName) throws UnsupportedEncodingException {response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");response.setCharacterEncoding("utf-8");String fileName = URLEncoder.encode(rawFileName, "UTF-8").replaceAll("%20", File.separator+"+");response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");}/*** 读取学生列表数据** @return 学生数据* @throws IOException IO异常*/private List<StudentDo> getStudentList() throws IOException {ObjectMapper objectMapper = new ObjectMapper();ClassPathResource classPathResource = new ClassPathResource("data/students.json");InputStream inputStream = classPathResource.getInputStream();return objectMapper.readValue(inputStream, new TypeReference<List<StudentDo>>() {});}
}

json:将JSON数据放在resource/data下即可

[{"id": 1,"studentName": "张三","password": "1234","birthday": "2000-01-01","height": "170.5","gender": 0},{"id": 2,"studentName": "李四","password": "1234","birthday": "2000-01-02","height": "175.5","gender": 1},{"id": 3,"studentName": "王五","password": "1234","birthday": "2000-01-03","height": "180.5","gender": 1},{"id": 4,"studentName": "赵六","password": "1234","birthday": "2000-01-04","height": "176.5","gender": 0}
]

测试：

使用postman进行测试，选择“Send and Download”选项。

复杂表头一对多导出：

由于 EasyPoi 支持嵌套对象导出，直接使用内置 @ExcelCollection 注解即可实现，但是 EasyExcel 不支持一对多导出，只能自行实现，可以通过自定义合并策略方式来实现一对多导出。

自定义注解

@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExcelMerge {/*** 是否合并单元格** @return true || false*/boolean merge() default true;/*** 是否为主键（即该字段相同的行合并）** @return true || false*/boolean isPrimaryKey() default false;
}

定义实体类

需要合并的字段上标明@ExcelMerge

二级表头通过@ExcelProperty(value = {"学生信息","学生编号"})设置

@Data
public class SchoolDo {@ExcelProperty("学校编号")@ColumnWidth(20)@ExcelMerge(merge = true,isPrimaryKey = true)private String schoolId;@ExcelProperty("学校名")@ColumnWidth(20)@ExcelMerge(merge = true)private String schoolName;@ExcelProperty(value = {"学生信息","学生编号"})@ColumnWidth(20)private Long studentId;@ExcelProperty(value = {"学生信息","学生名"})@ColumnWidth(20)private String studentName;@ExcelIgnoreprivate String password;@ExcelProperty(value = {"学生信息","生日"})@ColumnWidth(20)@DateTimeFormat("yyyy-MM-dd")private Date birthday;@ExcelProperty(value = {"学生信息","身高（米）"})@NumberFormat("#.##")@ColumnWidth(20)private Double height;@ExcelProperty(value = {"学生信息","性别"},converter = GenderConverter.class)@ColumnWidth(10)private Integer gender;
}

自定义单元格合并策略

当 Excel 中两列主键相同时，合并被标记需要合并的列，将自定义合并策略 ExcelMergeStrategy 通过 registerWriteHandler 注册上去：


public class ExcelMergeStrategy implements RowWriteHandler {/*** 主键下标*/private Integer primaryKeyIndex;/*** 需要合并的列的下标集合*/private final List<Integer> mergeColumnIndexList = new ArrayList<>();/*** 数据类型*/private final Class<?> elementType;public ExcelMergeStrategy(Class<?> elementType) {this.elementType = elementType;}@Overridepublic void afterRowDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Integer relativeRowIndex, Boolean isHead) {// 判断是否为标题if (isHead) {return;}// 获取当前工作表Sheet sheet = writeSheetHolder.getSheet();// 初始化主键下标和需要合并字段的下标if (primaryKeyIndex == null) {this.initPrimaryIndexAndMergeIndex(writeSheetHolder);}// 判断是否需要和上一行进行合并// 不能和标题合并，只能数据行之间合并if (row.getRowNum() <= 1) {return;}// 获取上一行数据Row lastRow = sheet.getRow(row.getRowNum() - 1);// 将本行和上一行是同一类型的数据（通过主键字段进行判断），则需要合并if (lastRow.getCell(primaryKeyIndex).getStringCellValue().equalsIgnoreCase(row.getCell(primaryKeyIndex).getStringCellValue())) {for (Integer mergeIndex : mergeColumnIndexList) {CellRangeAddress cellRangeAddress = new CellRangeAddress(row.getRowNum() - 1, row.getRowNum(), mergeIndex, mergeIndex);sheet.addMergedRegionUnsafe(cellRangeAddress);}}}/*** 初始化主键下标和需要合并字段的下标** @param writeSheetHolder WriteSheetHolder*/private void initPrimaryIndexAndMergeIndex(WriteSheetHolder writeSheetHolder) {// 获取当前工作表Sheet sheet = writeSheetHolder.getSheet();// 获取标题行Row titleRow = sheet.getRow(0);// 获取所有属性字段Field[] fields = this.elementType.getDeclaredFields();// 遍历所有字段for (Field field : fields) {// 获取@ExcelProperty注解，用于获取该字段对应列的下标ExcelProperty excelProperty = field.getAnnotation(ExcelProperty.class);// 判断是否为空if (null == excelProperty) {continue;}// 获取自定义注解，用于合并单元格ExcelMerge excelMerge = field.getAnnotation(ExcelMerge.class);// 判断是否需要合并if (null == excelMerge) {continue;}for (int i = 0; i < fields.length; i++) {Cell cell = titleRow.getCell(i);if (null == cell) {continue;}// 将字段和表头匹配上if (excelProperty.value()[0].equalsIgnoreCase(cell.getStringCellValue())) {if (excelMerge.isPrimaryKey()) {primaryKeyIndex = i;}if (excelMerge.merge()) {mergeColumnIndexList.add(i);}}}}// 没有指定主键，则异常if (null == this.primaryKeyIndex) {throw new IllegalStateException("使用@ExcelMerge注解必须指定主键");}}
}

测试一下

 @GetMapping("/export/school")public void exportOrderExcel(HttpServletResponse response) {try {this.setExcelResponseProp(response, "学校列表");List<SchoolDo> exportData = this.getSchoolList();EasyExcel.write(response.getOutputStream()).head(SchoolDo.class).registerWriteHandler(new ExcelMergeStrategy(SchoolDo.class)).excelType(ExcelTypeEnum.XLSX).sheet("学校列表").doWrite(exportData);} catch (IOException e) {throw new RuntimeException(e);}}
/*** 读取学校列表数据** @return 列表数据* @throws IOException IO异常*/private List<SchoolDo> getSchoolList() throws IOException {ObjectMapper objectMapper = new ObjectMapper();ClassPathResource classPathResource = new ClassPathResource("data/schools.json");InputStream inputStream = classPathResource.getInputStream();return objectMapper.readValue(inputStream, new TypeReference<List<SchoolDo>>() {});}

json数据：

[{"schoolId":"1","schoolName":"北京大学","studentId": 1,"studentName": "张三","password": "1234","birthday": "2000-01-01","height": "170.5","gender": 0},{"schoolId":"1","schoolName":"北京大学","studentId": 2,"studentName": "李四","password": "1234","birthday": "2000-01-02","height": "175.5","gender": 1},{"schoolId":"1","schoolName":"北京大学","studentId": 3,"studentName": "王五","password": "1234","birthday": "2000-01-03","height": "180.5","gender": 1},{"schoolId":"1","schoolName":"北京大学","studentId": 4,"studentName": "赵六","password": "1234","birthday": "2000-01-04","height": "176.5","gender": 0},{"schoolId":"2","schoolName":"河北大学","studentId": 1,"studentName": "张三","password": "1234","birthday": "2000-01-01","height": "170.5","gender": 0},{"schoolId":"2","schoolName":"河北大学","studentId": 2,"studentName": "李四","password": "1234","birthday": "2000-01-02","height": "175.5","gender": 1},{"schoolId":"2","schoolName":"河北大学","studentId": 3,"studentName": "王五","password": "1234","birthday": "2000-01-03","height": "180.5","gender": 1},{"schoolId":"2","schoolName":"河北大学","studentId": 4,"studentName": "赵六","password": "1234","birthday": "2000-01-04","height": "176.5","gender": 0}
]

测试：

使用postman进行测试，选择“Send and Download”选项。