Easyexcel read write simple to use

Official documents https://easyexcel.opensource.alibaba.com/docs/current/quickstart/read

One . Read

1.1 Defining entity classes

@Data
public class EmailImportParam implements Serializable {
    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = " Data adding method  1  The system automatically finds the registered company name through the email domain name  2  Manual input ")
    @NotNull
    @ExcelProperty(index = 0)
    private Integer dataType;

    @ApiModelProperty(value = " Alternate company name ")
    @ExcelProperty(index = 1)
    private String inputCompanyName;

    @ApiModelProperty(value = " Email address ")
    @NotBlank
    @ExcelProperty(index = 2)
    private String email;

}

• If you don't use headings @ExcelProperty(index = 0), Title From 0 Turn on
• If you use the title @ExcelProperty(" Data adding method ")

1.2 Do not check data batch import

Interface implementation

    @Override
    @SneakyThrows
    public Boolean importExcel(MultipartFile file) {
        EasyExcel.read(file.getInputStream(), EmailImportParam.class, new EmailDataListener(this)).sheet().doRead();
        return true;
    }

add to EmailDataListener

package com.tophant.pentestinfoinv.listener;

import cn.hutool.json.JSONUtil;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.read.listener.ReadListener;
import com.alibaba.excel.util.ListUtils;
import com.tophant.pentestinfoinv.common.domain.query.EmailAddParam;
import com.tophant.pentestinfoinv.common.domain.query.EmailImportParam;
import com.tophant.pentestinfoinv.service.IEmailService;
import lombok.extern.slf4j.Slf4j;

import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * @Description email excel Import listening class 
 * @Author WanFei
 * @Date 2022/7/4 16:43
 **/
@Slf4j
public class EmailDataListener implements ReadListener<EmailImportParam> {

    /**
     *  every other 5 Storage database , It can be used in practice 100 strip , Then clean up list , Convenient for memory recycling 
     */
    private static final int BATCH_COUNT = 100;
    private List<EmailImportParam> cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
    /**
     *  Suppose this is a DAO, Of course, there is business logic, which can also be a service. Of course, it's useless if you don't have to store this object .
     */
    private IEmailService emailService;

    /**
     *  If used spring, Please use this construction method . Each creation Listener You need to put spring The management class came in 
     *
     * @param emailService
     */
    public EmailDataListener(IEmailService emailService) {
        this.emailService = emailService;
    }

    /**
     *  Every data parsing will call 
     *
     * @param data    one row value. Is is same as {@link AnalysisContext#readRowHolder()}
     * @param context
     */
    @Override
    public void invoke(EmailImportParam data, AnalysisContext context) {
        log.info(" Parse to a piece of data :{}", JSONUtil.toJsonStr(data));
        cachedDataList.add(data);
        //  achieve BATCH_COUNT 了 , Need to store the database once , Prevent tens of thousands of data in memory , Easy to OOM
        if (cachedDataList.size() >= BATCH_COUNT) {
            saveData();
            //  Storage complete cleaning  list
            cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
        }
    }

    /**
     *  All data analysis is done   Will call 
     *
     * @param context
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        //  We also need to save data here , Make sure that the last legacy data is also stored in the database 
        saveData();
        log.info(" All data analysis completed ！");
    }

    /**
     *  Plus the storage database 
     */
    private void saveData() {
        log.info("{} Data , Start storing the database ！", cachedDataList.size());
        List<EmailAddParam> emailAddParams = cachedDataList.stream().map(emailImportParam -> new EmailAddParam()
                .setEmails(Set.of(emailImportParam.getEmail()))
                .setDataType(emailImportParam.getDataType())
                .setInputCompanyName(emailImportParam.getInputCompanyName()))
                .collect(Collectors.toList());
        emailAddParams.forEach(emailService::create);
        log.info(" Storage database success ！");
    }
}

1.3 Check the one-time import of data

    @Override
    @SneakyThrows
    public Boolean importExcel(MultipartFile file) {
        File newFile = MultipartFileUtil.multipartFileToFile(file);
        Assert.isFalse(ObjectUtil.isNull(file) || ObjectUtil.isNull(newFile), " The file cannot be empty !");
        //  Get file type 
        String fileType = FileUtil.getType(newFile);
        log.info(" Upload file extension : {}", fileType);
        Assert.notNull(fileType, " The extension name of the uploaded file is empty ！");
        Assert.isTrue(StrUtil.containsAnyIgnoreCase(fileType, "xls", "xlsx"), StrUtil.format(" Upload of file type is not allowed : {}", fileType));

        List<EmailImportParam> emailList = new ArrayList<>();
        EasyExcel.read(file.getInputStream()).head(EmailImportParam.class)
                .sheet()
                .registerReadListener(new AnalysisEventListener<EmailImportParam>() {
                    @Override
                    public void invoke(EmailImportParam data, AnalysisContext context) {
                        emailList.add(data);
                    }

                    @Override
                    public void doAfterAllAnalysed(AnalysisContext context) {
                        log.info(" Data read complete ");
                    }
                }).doRead();
        Set<String> emails = emailList.stream().map(EmailImportParam::getEmail).collect(Collectors.toSet());
        InfoInvUtil.checkDomain(emails);

        //  Query the existing mailbox 
        Set<String> repeatEmails = this.lambdaQuery()
                .eq(Email::getDelFlag, false)
                .in(Email::getEmail, emails)
                .select(Email::getEmail)
                .list()
                .stream()
                .map(Email::getEmail)
                .collect(Collectors.toSet());
        Assert.isFalse(CollUtil.isNotEmpty(repeatEmails), StrUtil.format(" mailbox : {}  Already exists ,  Please check excel file ", CollUtil.join(repeatEmails, ", ")));

        //  Add to database 
        List<EmailAddParam> emailAddParams = emailList.stream().map(emailImportParam -> new EmailAddParam()
                        .setEmails(Set.of(emailImportParam.getEmail()))
                        .setDataType(emailImportParam.getDataType())
                        .setInputCompanyName(emailImportParam.getInputCompanyName()))
                .collect(Collectors.toList());
        emailAddParams.forEach(this::create);
        return true;
    }

MultipartFileUtil Tool class

package com.tophant.pentestinfoinv.common.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Objects;

/**
 * File Transformation tool 
 *
 * @author [email protected]
 * @date 06-21-0021-2021
 */
@Slf4j
public class MultipartFileUtil {
    /**
     * MultipartFile Convert to File
     *
     * @param file multipartFile
     * @return File
     * @throws Exception
     */
    public static File multipartFileToFile(MultipartFile file) {
        try {
            File toFile = null;
            if (file.equals("") || file.getSize() <= 0) {
                file = null;
            } else {
                InputStream ins = null;
                ins = file.getInputStream();
                toFile = new File(Objects.requireNonNull(file.getOriginalFilename()));
                inputStreamToFile(ins, toFile);
                ins.close();
            }
            return toFile;
        } catch (Exception e) {
            log.warn("MultipartFile Turn into File Failure ！");
            return null;
        }
    }

    /**
     *  Get stream file 
     * @param ins
     * @param file
     */
    private static void inputStreamToFile(InputStream ins, File file) {
        try {
            OutputStream os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            ins.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Two . write in

2.1 write in

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        EasyExcel.write(byteArrayOutputStream, EmailExcelVO.class)
                //  Register a custom interceptor 
                .registerWriteHandler(new CustomCellWriteConfig())
                .registerWriteHandler(new CustomColumnWidthConfig())
                .registerWriteHandler(new CustomRowHeightConfig())
                .sheet(" mailbox ")
                .doWrite(excelVOList);

2.2 Custom interceptors

2.2.1 Set the style

package com.tophant.component.starter.excel.common.config;

import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.write.handler.CellWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import org.apache.poi.ss.usermodel.*;

import java.util.List;

/**
 * @Description  Set the style 
 * @Author WanFei
 * @Date 2022/5/13 12:13
 */
public class CustomCellWriteConfig implements CellWriteHandler {
    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List<WriteCellData<?>> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        Workbook workbook = writeSheetHolder.getSheet().getWorkbook();
        CellStyle cellStyle = workbook.createCellStyle();
        //  In the middle 
        cellStyle.setAlignment(HorizontalAlignment.LEFT);
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
        //  Set borders 
        cellStyle.setBorderBottom(BorderStyle.THIN);
        cellStyle.setBorderLeft(BorderStyle.THIN);
        cellStyle.setBorderRight(BorderStyle.THIN);
        cellStyle.setBorderTop(BorderStyle.THIN);
        //  Word wrap 
        cellStyle.setWrapText(true);
        //  Configuration takes effect 
        cell.setCellStyle(cellStyle);
    }
}

2.2.2 Adaptive width

package com.tophant.component.starter.excel.common.config;

import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.metadata.data.CellData;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Sheet;
import org.springframework.util.CollectionUtils;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @Description  Adaptive width 
 * @Author WanFei
 * @Date 2022/5/13 13:59
 */
public class CustomColumnWidthConfig extends AbstractColumnWidthStyleStrategy {
    private Map<Integer, Map<Integer, Integer>> CACHE = new HashMap<>();

    @Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<WriteCellData<?>> cellDataList, Cell cell, Head head, Integer integer, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
        if (needSetWidth) {
            Map<Integer, Integer> maxColumnWidthMap = CACHE.computeIfAbsent(writeSheetHolder.getSheetNo(), k -> new HashMap<>());

            Integer columnWidth = this.dataLength(cellDataList, cell, isHead);
            if (columnWidth >= 0) {
                if (columnWidth > 254) {
                    columnWidth = 254;
                }

                Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());
                if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
                    maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);
                    Sheet sheet = writeSheetHolder.getSheet();
                    sheet.setColumnWidth(cell.getColumnIndex(), columnWidth * 256);
                }

            }
        }
    }

    /**
     *  Calculate the length 
     * @param cellDataList
     * @param cell
     * @param isHead
     * @return
     */
    private Integer dataLength(List<WriteCellData<?>> cellDataList, Cell cell, Boolean isHead) {
        if (isHead) {
            return cell.getStringCellValue().getBytes().length;
        } else {
            CellData<?> cellData = cellDataList.get(0);
            CellDataTypeEnum type = cellData.getType();
            if (type == null) {
                return -1;
            } else {
                switch (type) {
                    case STRING:
                        //  A newline （ The data needs to be parsed in advance ）
                        int index = cellData.getStringValue().indexOf("\n");
                        return index != -1 ?
                                cellData.getStringValue().substring(0, index).getBytes().length + 1 : cellData.getStringValue().getBytes().length + 1;
                    case BOOLEAN:
                        return cellData.getBooleanValue().toString().getBytes().length;
                    case NUMBER:
                        return cellData.getNumberValue().toString().getBytes().length;
                    default:
                        return -1;
                }
            }
        }
    }
}

2.2.3 Adaptive line height

package com.tophant.component.starter.excel.common.config;

import com.alibaba.excel.write.style.row.AbstractRowHeightStyleStrategy;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;

import java.util.Iterator;

/**
 * @Description  Adaptive line height 
 * @Author WanFei
 * @Date 2022/5/13 14:03
 */
public class CustomRowHeightConfig extends AbstractRowHeightStyleStrategy {
    /**
     *  Default height 
     */
    private static final Integer DEFAULT_HEIGHT = 300;

    @Override
    protected void setHeadColumnHeight(Row row, int relativeRowIndex) {
    }

    @Override
    protected void setContentColumnHeight(Row row, int relativeRowIndex) {
        Iterator<Cell> cellIterator = row.cellIterator();
        if (!cellIterator.hasNext()) {
            return;
        }

        //  The default is  1 Line height 
        Integer maxHeight = 1;
        while (cellIterator.hasNext()) {
            Cell cell = cellIterator.next();
            switch (cell.getCellType()) {
                case STRING:
                    if (cell.getStringCellValue().contains("\n")) {
                        int length = cell.getStringCellValue().split("\n").length;
                        maxHeight = Math.max(maxHeight, length);
                    }
                    break;
                default:
                    break;
            }
        }

        row.setHeight((short) (maxHeight * DEFAULT_HEIGHT));
    }
}