EasyExcel导入（简单好用）

工具类

package com.**.util;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.rail.tams.common.exception.Exceptions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

/**
 * excel工具类
 * easyexcel使用的3.0.2版本，跟以前版本有很大区别，且不兼容1.x版本
 */
public class EasyExcelUtil {
    private static final Logger LOGGER = LoggerFactory.getLogger(EasyExcelUtil.class);

    public static  List read(String filePath, final Class clazz) {
        File f = new File(filePath);
        try (FileInputStream fis = new FileInputStream(f)) {
            return read(fis, clazz);
        } catch (FileNotFoundException e) {
            LOGGER.error("文件{}不存在", filePath, e);
        } catch (IOException e) {
            LOGGER.error("文件读取出错", e);
        }
        return null;
    }

    public static  List read(InputStream inputStream, final Class clazz) {
        if (inputStream == null) {
            throw Exceptions.newMessageException("解析出错了，文件流是null");
        }
        // 有个很重要的点 DataListener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去
        DataListener listener = new DataListener<>();
        // 这里 需要指定读用哪个class去读，然后读取第一个sheet 文件流会自动关闭
        EasyExcel.read(inputStream, clazz, listener).sheet().doRead();
        return listener.getRows();
    }

    public static void write(String outFile, List list) {
        Class clazz = list.get(0).getClass();
        EasyExcel.write(outFile, clazz).sheet().doWrite(list);
    }

    public static void write(String outFile, List list, String sheetName) {
        Class clazz = list.get(0).getClass();
        EasyExcel.write(outFile, clazz).sheet(sheetName).doWrite(list);
    }

    public static void write(OutputStream outputStream, List list, String sheetName) {
        Class clazz = list.get(0).getClass();
        // sheetName为sheet的名字，默认写第一个sheet
        EasyExcel.write(outputStream, clazz).sheet(sheetName).doWrite(list);
    }

    /**
     * 文件下载（失败了会返回一个有部分数据的Excel），用于直接把excel返回到浏览器下载
     */
    public static void download(HttpServletResponse response, List list, String sheetName) throws IOException {
        Class clazz = list.get(0).getClass();
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系
        String fileName = URLEncoder.encode(sheetName, "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
        EasyExcel.write(response.getOutputStream(), clazz).head(clazz).sheet(sheetName).doWrite(list);
    }
}

class DataListener extends AnalysisEventListener {

    private static final Logger LOGGER = LoggerFactory.getLogger(DataListener.class);

    private final List rows = new ArrayList<>();

    @Override
    public void invoke(T t, AnalysisContext analysisContext) {
        rows.add(t);
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        LOGGER.info("解析完成！读取{}行", rows.size());
    }

    public List getRows() {
        return rows;
    }
}

下载导入模板

    @GetMapping("/downloadImportFileSubject")
    public void downloadImportFileSubject(HttpServletResponse response) throws IOException 
    {
        List list = new ArrayList<>();
        list.add(new OutEvalTopic());
        EasyExcelUtil.download(response, list, "模板");
    }

实体部分代码

import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.ExcelIgnoreUnannotated;
@ExcelIgnoreUnannotated   
public class{
    @ExcelProperty(value = "课题名称", index = 1)
    private String name;

    @ExcelProperty(value = "课题类别", index = 2)
    private String type;
}

导入

   @RequestMapping("/importExcelSubject")
    public Resp importExcelSubject(MultipartFile file) throws IOException {
        List list = EasyExcelUtil.read(file.getInputStream(),                                 
        OutEvalTopic.class);
        outEvalDeclareService.saveBatchTopic(list);
        return Resp.ok(list);
    }