EasyExcel实现写操作实践

EasyExcel实现写操作实践

导入依赖

<!--easyexcel-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>2.1.1</version>
</dependency>
<!--xls-->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
</dependency>

映射写入实体类

@Data
public class DemoData {
    //设置excel表头名称
    @ExcelProperty("学生编号")
    private Integer sno;
    @ExcelProperty("学生姓名")
    private String sname;
}

实现excel写操作

    public static void main(String[] args) {
        //实现excel写操作
        // 1. 设置写入文件夹地址和excel文件名称
        String filename = "E:\\write.xlsx";
        
        // 2. 调用easyexcel里面的方法实现写操作
        // 第一个参数文件路径名称 第二个参数实体类class doWrite(要写入的数据)
        EasyExcel.write(filename, DemoData.class).sheet("学生列表").doWrite(getData());
    }

    // 创建方法返回list集合
    private static List<DemoData> getData() {
        List<DemoData> list = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            DemoData data = new DemoData();
            data.setSno(i);
            data.setSname("lucy" + i);
            list.add(data);
        }
        return list;
    }

EasyExcel实现读操作

映射读出实体类

@Data
public class DemoData {
    //设置excel表头名称
    @ExcelProperty(value = "学生编号",index = 0)
    private Integer sno;
    @ExcelProperty(value = "学生姓名" ,index = 1)
    private String sname;
}

创建读取操作的监听器

public class ExcelListener extends AnalysisEventListener<DemoData> {
    // 一行一行读取excel内容
    @Override
    public void invoke(DemoData demoData, AnalysisContext analysisContext) {
        System.out.println("****" + demoData + "****");
    }

    // 读取表头内容
    @Override
    public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
        System.out.println("表头" + headMap);
    }

    // 读取完成之后
    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {

    }

}

实现excel读操作

@Test
public void read(){
    // 需要读的excel
    String filename="E:\\write.xlsx";
    // 第一个参数文件路径名称 第二个参数实体类class 第三个参数监听器对象
    EasyExcel.read(filename,DemoData.class,new ExcelListener()).sheet().doRead();
}

使用EasyExcel进行有二级分类的课程添加实践

映射excel对象

@Data
public class SubjectData {

    @ExcelProperty(index = 0)
    private String onSubjectName;

    @ExcelProperty(index = 1)
    private String twoSubjectName;
}

excel.xlsx

一级分类    二级分类
前端开发    react
后端开发    java
数据库开发   orancle

controller层

    // 添加课程分类
    // 获取上传过来的文件，把文件内容读取出来
    @PostMapping("addSubject")
    public R eduSubject(MultipartFile file) {
        // 上传过来的excel
        eduSubjectService.saveSubject(file,eduSubjectService);
        return R.ok();
    }

service层

    // 添加课程分类
    @Override
    public void saveSubject(MultipartFile file, EduSubjectService eduSubjectService) {
        try {
            //文件输入溜
            InputStream in = file.getInputStream();
            EasyExcel.read(in, SubjectData.class, new SubjectExcelListener(eduSubjectService)).sheet().doRead();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

easyexcel监听器

public class SubjectExcelListener extends AnalysisEventListener<SubjectData> {

    // 因为SubjectExcelListener不能交给spring进行管理，需要自己new，不能注入其他对象
    // 因此不能实现数据库操作，因此要手动注入
    public EduSubjectService subjectService;

    public SubjectExcelListener() {
    }

    public SubjectExcelListener(EduSubjectService subjectService) {
        this.subjectService = subjectService;
    }

    // 读取excel内容，一行一行进行读取
    @Override
    public void invoke(SubjectData subjectData, AnalysisContext analysisContext) {
        if (subjectData == null) {
            throw new MyException(20001, "文件数据为空");
        }

        // 一行一行读取，每次读取有二个值，第一个值是一级分类，第二个值是二级分类
        // 判断一级分类是否重复
        EduSubject existOneSubject = this.existOneSubject(subjectService, subjectData.getOnSubjectName());
        if (existOneSubject == null) {
            existOneSubject = new EduSubject();
            existOneSubject.setParentId("0");
            existOneSubject.setTitle(subjectData.getOnSubjectName());
            subjectService.save(existOneSubject);

        }
        // 获取一级分类id值
        String pid = existOneSubject.getId();
        // 判断二级分类是否重复
        EduSubject existTwoSubject = this.existTwoSubject(subjectService, subjectData.getTwoSubjectName(), pid);
        if (existTwoSubject == null) {
            existTwoSubject = new EduSubject();
            existTwoSubject.setParentId(pid);
            existTwoSubject.setTitle(subjectData.getTwoSubjectName());
            subjectService.save(existTwoSubject);
        }


    }

    // 判断一级分类不能重复添加
    private EduSubject existOneSubject(EduSubjectService subjectService, String name) {
        QueryWrapper<EduSubject> wrapper = new QueryWrapper<>();
        wrapper.eq("title", name);
        wrapper.eq("parent_id", "0");
        EduSubject oneSubject = subjectService.getOne(wrapper);
        return oneSubject;

    }

    // 判断二级分类不能重复添加
    private EduSubject existTwoSubject(EduSubjectService subjectService, String name, String pid) {
        QueryWrapper<EduSubject> wrapper = new QueryWrapper<>();
        wrapper.eq("title", name);
        wrapper.eq("parent_id", pid);
        EduSubject twoSubject = subjectService.getOne(wrapper);
        return twoSubject;
    }


    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {

    }
}