基于easyexcel做导入

准备工作:
1.一个excel文件如下图

2.项目中带入maven

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.17</version>
</dependency>
<!--xlsx格式excel依赖包-->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.17</version>
</dependency>
<!-- easyexcel依赖包 -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>1.1.2-beat1</version>
</dependency>

具体操作步骤如下:

1.新建实体类 --用于接收excel中的数据

import com.alibaba.excel.annotation.ExcelProperty; 
import com.alibaba.excel.metadata.BaseRowModel;

public class Catagory extends BaseRowModel {
    @ExcelProperty(value = "id", index = 0)
    private Integer id;

    @ExcelProperty(value = "name", index = 1)
    private String name;

    @Override
    public String toString() {
        return "Catagory{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }

    public Catagory() {
    }

    public Catagory(Integer id, String name) {

        this.id = id;
        this.name = name;
    }

    public Integer getId() {

        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

2.编写一个监听类 --用于excel转换使用

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import java.util.ArrayList;
import java.util.List;

public class ExcelListener extends AnalysisEventListener {
    
    //自定义用于暂时存储data
    //private List<Object> datas = Collections.synchronizedList(new ArrayList<>());
    private List<Object> datas = new ArrayList<>();

    /**
     * 通过 AnalysisContext 对象还可以获取当前 sheet，当前行等数据
     */
    @Override
    public void invoke(Object o, AnalysisContext analysisContext) {
        datas.add(o);
    }

    /**
     * 读取完之后的操作
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {

    }

    public List<Object> getDatas() {
        return datas;
    }

    public void setDatas(List<Object> datas) {
        this.datas = datas;
    }

3.编写导入工具类

import com.alibaba.excel.ExcelReader;
import com.alibaba.excel.metadata.BaseRowModel;
import com.alibaba.excel.metadata.Sheet;
import org.springframework.web.multipart.MultipartFile;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class EasyExcelUtil {

    /**
     * 读取某个 sheet 的 Excel
     *
     * @param excel    文件
     * @param rowModel 实体类映射，继承 BaseRowModel 类
     * @param sheetNo  sheet 的序号 从1开始
     * @return Excel 数据 list
     */
    public static List<Object> readExcel(MultipartFile excel, BaseRowModel rowModel) throws IOException {
        return readExcel(excel, rowModel, 1, 1);
    }

    /**
     * 读取某个 sheet 的 Excel
     * @param excel       文件
     * @param rowModel    实体类映射，继承 BaseRowModel 类
     * @param sheetNo     sheet 的序号 从1开始
     * @param headLineNum 表头行数，默认为1
     * @return Excel 数据 list
     */
    public static List<Object> readExcel(MultipartFile excel, BaseRowModel rowModel, int sheetNo, int headLineNum) throws IOException {
        ExcelListener excelListener = new ExcelListener();
        ExcelReader reader = getReader(excel, excelListener);
        if (reader == null) {
            return null;
        }
        reader.read(new Sheet(sheetNo, headLineNum, rowModel.getClass()));
        return excelListener.getDatas();
    }

    /**
     * 读取指定sheetName的Excel(多个 sheet)
     * @param excel    文件
     * @param rowModel 实体类映射，继承 BaseRowModel 类
     * @return Excel 数据 list
     * @throws IOException
     */
    public static List<Object> readExcel(MultipartFile excel, BaseRowModel rowModel,String sheetName) throws IOException {
        ExcelListener excelListener = new ExcelListener();
        ExcelReader reader = getReader(excel, excelListener);
        if (reader == null) {
            return null;
        }
        for (Sheet sheet : reader.getSheets()) {
            if (rowModel != null) {
                sheet.setClazz(rowModel.getClass());
            }
            //读取指定名称的sheet
            if(sheet.getSheetName().contains(sheetName)){
                reader.read(sheet);
                break;
            }
        }
        return excelListener.getDatas();
    }

    /**
     * 返回 ExcelReader
     * @param excel 需要解析的 Excel 文件
     * @param excelListener new ExcelListener()
     * @throws IOException
     */
    private static ExcelReader getReader(MultipartFile excel,ExcelListener excelListener) throws IOException {
        String filename = excel.getOriginalFilename();
        if(filename != null && (filename.toLowerCase().endsWith(".xls") || filename.toLowerCase().endsWith(".xlsx"))){
            InputStream is = new BufferedInputStream(excel.getInputStream());
            return new ExcelReader(is, null, excelListener, false);
        }else{
            return null;
        }
    }

4.controller层调用 --调用工具类读取excel中内容并将其封装到对象中

@RequestMapping(value = "importExcel", method = {RequestMethod.GET, RequestMethod.POST })
public void importExcel( @RequestParam("file") MultipartFile file) throws Exception {

        List<Object> list = EasyExcelUtil.readExcel(file, new Catagory(),1,1);	//根据实际改动new Catagory()
        if(list != null && list.size() > 0){
            for(Object o : list){
                Catagory catagory = (Catagory) o;
                System.out.println(catagory.getId()+"/"+catagory.getName());
            }
        }
}

5.前段element ui

<div>
  <el-upload
    class="upload-demo"
    drag
    action="http://localhost:8080/terminal/importExcel"
    multiple>
    <i class="el-icon-upload"></i>
    <div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>
    <div class="el-upload__tip" slot="tip">只能上传jpg/png文件，且不超过500kb</div>
  </el-upload>
</div>

参考: https://www.cnblogs.com/bbllw/p/11122357.html