EasyExcel

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。

引入依赖

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

表结构

学生表

CREATE TABLE `student`  (
  `id` bigint UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '学生表ID',
  `sname` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '学生姓名',
  `sno` bigint NOT NULL COMMENT '学号',
  `sex` char(2) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '性别',
  `age` int NOT NULL COMMENT '年龄',
  `is_deleted` tinyint UNSIGNED NOT NULL DEFAULT 0 COMMENT '是否删除',
  PRIMARY KEY (`id`)
);

课程表

CREATE TABLE `course`  (
  `id` bigint UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '课程表ID',
  `cname` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '课程名',
  `cno` bigint NOT NULL COMMENT '课程号',
  `tno` bigint NOT NULL COMMENT '任教教师编码',
  `is_deleted` tinyint(1) UNSIGNED NOT NULL DEFAULT 0 COMMENT '是否删除',
  PRIMARY KEY (`id`)
);

教师表

CREATE TABLE `teacher`  (
  `id` bigint UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '教师表ID',
  `tname` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '教师姓名',
  `tno` bigint NOT NULL COMMENT '教师编号',
  `sex` char(2) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '性别',
  `age` int NOT NULL COMMENT '年龄',
  `is_deleted` tinyint(1) UNSIGNED NOT NULL DEFAULT 0 COMMENT '是否删除',
  PRIMARY KEY (`id`)
);

多sheet上传时已上传了部分数据，所以表中目前有数据

项目结构

下载模板实体类

StudentVo

@Data
public class StudentVo {

    /**学生姓名**/
    @ExcelProperty(value = "姓名",index = 0)
    private String sname;
    /**学号**/
    @ExcelProperty(value = "学号",index = 1)
    private Long sno;
    /**性别**/
    @ExcelProperty(value = "性别",index = 2)
    private String sex;
    /**年龄**/
    @ExcelProperty(value = "年龄",index = 3)
    private Integer age;

}

CourseVo

@Data
public class CourseVo {
    /**课程名**/
    @ExcelProperty(value = "课程名",index = 0)
    private String cname;
    /**课程号**/
    @ExcelProperty(value = "课程号",index = 1)
    private Long cno;
    /**任教教师编号**/
    @ExcelProperty(value = "任教教师编号",index = 2)
    private Long tno;
}

TeacherVo

@Data
public class TeacherVo {
    /**教师姓名**/
    @ExcelProperty(value = "姓名", index = 0)
    private String tname;
    /**教师编号**/
    @ExcelProperty(value = "教师编号", index = 1)
    private Long tno;
    /**性别**/
    @ExcelProperty(value = "性别", index = 2)
    private String sex;
    /**年龄**/
    @ExcelProperty(value = "年龄", index = 3)
    private Integer age;
}

Controller

@RestController
@RequestMapping("/easyExcel")
public class EasyExcelController {

	@Resource
    private IEasyExcelService easyExcelService;

    @PostMapping("excelExport")
    public void excelExport(HttpServletResponse response){
        easyExcelService.excelExport(response);
    }
}

Service

EasyExcelService

public interface IEasyExcelService {
    void excelExport(HttpServletResponse response);
}

StudentService

public interface IStudentService extends IService<Student> {
}

CourseService

public interface ICourseService extends IService<Course> {
}

TeacherService

public interface ITeacherService extends IService<Teacher> {
}

ServiceImpl

EasyExcelServiceImpl

@Service
public class EasyExcelServiceImpl implements IEasyExcelService {

    @Resource
    private StudentMapper studentMapper;
    @Resource
    private CourseMapper courseMapper;
    @Resource
    private TeacherMapper teacherMapper;

   @Override
    public void excelExport(HttpServletResponse response) {
        try {
            String fileName = "student";
            ExcelWriter excelWriter = EasyExcel.write(response.getOutputStream()).build();
            WriteSheet studentInfo = EasyExcel.writerSheet(0,"student")
                    .head(StudentVo.class).registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
                    .build();
            WriteSheet courseInfo = EasyExcel.writerSheet(1,"course")
                    .head(CourseVo.class).registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
                    .build();
            WriteSheet teacherInfo = EasyExcel.writerSheet(2,"teacher")
                    .head(TeacherVo.class).registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
                    .build();

            List<Student> studentList = studentMapper.selectList(null);
            List<Course> courseList = courseMapper.selectList(null);
            List<Teacher> teacherList = teacherMapper.selectList(null);
            excelWriter.write(studentList,studentInfo);
            excelWriter.write(courseList,courseInfo);
            excelWriter.write(teacherList,teacherInfo);
            response.setContentType("application/vnd.ms-excel;charset=utf-8");
            response.setCharacterEncoding("UTF-8");
            response.setHeader("Content-Disposition","attachment;filename="+fileName+".xlsx");
            excelWriter.finish();
        }catch (IOException e){
            e.printStackTrace();
        }
    }

StudentServiceImpl

@Service
public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student> implements IStudentService {
}

CourseServiceImpl

@Service
public class CourseServiceImpl extends ServiceImpl<CourseMapper, Course> implements ICourseService {
}

TeacherServiceImpl

@Service
public class TeacherServiceImpl extends ServiceImpl<TeacherMapper, Teacher> implements ITeacherService {
}

mapper

StudentMapper

public interface StudentMapper extends BaseMapper<Student> {
}

CourseMapper

public interface CourseMapper extends BaseMapper<Course> {
}

TeacherMapper

public interface TeacherMapper extends BaseMapper<Teacher> {
}

启动项目

测试

使用postman测试，测试方法如下


下载完成后，打开Excel表查看内容

操作完成