Java中使用EasyExcel写excel文件

 1、公式

package com.web.report.handler;

import com.alibaba.excel.context.WriteContext;
import com.alibaba.excel.metadata.csv.CsvCellStyle;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.write.handler.CellWriteHandler;
import com.alibaba.excel.write.handler.context.CellWriteHandlerContext;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.util.List;


@Slf4j
public class CustomCellWriteHandler implements CellWriteHandler {

    @Override
    public void afterCellDispose(CellWriteHandlerContext context) {
        Cell cell = context.getCell();
        // 这里可以对cell进行任何操作
        int rowIndex = cell.getRowIndex();
        String cellValue = cell.getStringCellValue();
        if (cellValue.startsWith("$$") && cellValue.endsWith("$$")) {
            String statisType = cellValue.substring(2, cellValue.length() - 2);
            String columnTitle = convertToTitle(cell.getColumnIndex() + 1);
            switch (statisType) {
                case "min":
                    cell.setCellFormula("min(" + columnTitle + (rowIndex + 5) + ":" + columnTitle + 1000000 + ")");
                    break;
                case "max":
                    cell.setCellFormula("max(" + columnTitle + (rowIndex + 4) + ":" + columnTitle + 1000000 + ")");
                    break;
//                case "testNum":
//                    cell.setCellFormula("COUNTA(A" + (rowIndex + 1 + 3) + ":A" + 1000000 + ")");
//                    break;
//                case "median":
//                    cell.setCellFormula("MEDIAN(" + columnTitle + (rowIndex + 3) + ":" + columnTitle + 1000000 + ")");
//                    break;
                case "avg":
                    cell.setCellFormula("IF(COUNT(" + columnTitle + (rowIndex + 3) + ":" + columnTitle + 1000000 + ")>0,AVERAGE(" + columnTitle + (rowIndex + 3) + ":" + columnTitle + 1000000 + "),0)");
                    break;
                case "stddev":
                    cell.setCellFormula("IF(COUNT(" + columnTitle + (rowIndex + 2) + ":" + columnTitle + 1000000 + ")>1,STDEV(" + columnTitle + (rowIndex + 2) + ":" + columnTitle + 1000000 + "),0)");
                    break;
            }
        } else {
            try {
                Double value = Double.valueOf(cellValue);
                cell.setCellValue(value);
            } catch (Exception e) {
            }
        }
    }
    public String convertToTitle(int n) {
        StringBuilder sb = new StringBuilder();
        while(n > 0){
            n--; // 重点
            sb.append((char)(n % 26 + 'A'));
            n /= 26;
        }
        sb.reverse();
        return sb.toString();
    }

}

2、合并

package com.web.report.handler;

import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.merge.AbstractMergeStrategy;
import org.apache.poi.ss.usermodel.Cell;

import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellRangeAddress;


public class CustomMergeStrategy extends AbstractMergeStrategy {

    private Integer columnLength;

    private Sheet sheet;

    public CustomMergeStrategy(Integer columnLength) {
        this.columnLength = columnLength;
    }

    // 合并成一个单元格
    private void mergeCommonColumn(Integer rowIndexStart, Integer rowIndexEnd,Integer columnIndexStart,Integer columnIndexEnd ) {
        CellRangeAddress cellRangeAddress = new CellRangeAddress(rowIndexStart, rowIndexEnd, columnIndexStart, columnIndexEnd);
        sheet.addMergedRegionUnsafe(cellRangeAddress);
    }

    @Override
    protected void merge(Sheet sheet, Cell cell, Head head, Integer integer) {
        this.sheet = sheet;
        if (cell.getRowIndex() < 13) {
            this.mergeCommonColumn(cell.getRowIndex(),cell.getRowIndex(),1,this.columnLength-1);
        }
    }

}

3、样式

package com.web.report.style;

import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import com.alibaba.excel.write.metadata.style.WriteFont;
import org.apache.poi.ss.usermodel.*;

public class StyleUtils {

    /**
     * 标题样式
     * @return
     */
    public static WriteCellStyle getHeadStyle(){
        // 头的策略
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        // 背景颜色
//        headWriteCellStyle.setFillForegroundColor(IndexedColors.LIGHT_TURQUOISE1.getIndex());
//        headWriteCellStyle.setFillPatternType(FillPatternType.SOLID_FOREGROUND);

        // 字体
//        WriteFont headWriteFont = new WriteFont();
//        headWriteFont.setFontName("宋体");//设置字体名字
//        headWriteFont.setFontHeightInPoints((short)14);//设置字体大小
//        headWriteFont.setBold(true);//字体加粗
//        headWriteCellStyle.setWriteFont(headWriteFont); //在样式用应用设置的字体;
//
//        // 样式
//        headWriteCellStyle.setBorderBottom(BorderStyle.THIN);//设置底边框;
//        headWriteCellStyle.setBottomBorderColor((short) 0);//设置底边框颜色;
//        headWriteCellStyle.setBorderLeft(BorderStyle.THIN);  //设置左边框;
//        headWriteCellStyle.setLeftBorderColor((short) 0);//设置左边框颜色;
//        headWriteCellStyle.setBorderRight(BorderStyle.THIN);//设置右边框;
//        headWriteCellStyle.setRightBorderColor((short) 0);//设置右边框颜色;
//        headWriteCellStyle.setBorderTop(BorderStyle.THIN);//设置顶边框;
//        headWriteCellStyle.setTopBorderColor((short) 0); //设置顶边框颜色;
//
//        headWriteCellStyle.setWrapped(true);  //设置自动换行;

        headWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);//设置水平对齐的样式为居中对齐;
        headWriteCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);  //设置垂直对齐的样式为居中对齐;
        headWriteCellStyle.setShrinkToFit(true);//设置文本收缩至合适

        return headWriteCellStyle;
    }


    /**
     * 内容样式
     * @return
     */
    public static WriteCellStyle getContentStyle(){
        // 内容的策略
        WriteCellStyle contentWriteCellStyle = new WriteCellStyle();

        // 背景绿色
        // 这里需要指定 FillPatternType 为FillPatternType.SOLID_FOREGROUND 不然无法显示背景颜色.头默认了 FillPatternType所以可以不指定
//        contentWriteCellStyle.setFillForegroundColor(IndexedColors.PALE_BLUE.getIndex());
//        contentWriteCellStyle.setFillPatternType(FillPatternType.SOLID_FOREGROUND);

        // 设置字体
//        WriteFont contentWriteFont = new WriteFont();
//        contentWriteFont.setFontHeightInPoints((short) 12);//设置字体大小
//        contentWriteFont.setFontName("宋体"); //设置字体名字
//        contentWriteCellStyle.setWriteFont(contentWriteFont);//在样式用应用设置的字体;
//
//        //设置样式;
//        contentWriteCellStyle.setBorderBottom(BorderStyle.THIN);//设置底边框;
//        contentWriteCellStyle.setBottomBorderColor((short) 0);//设置底边框颜色;
//        contentWriteCellStyle.setBorderLeft(BorderStyle.THIN);  //设置左边框;
//        contentWriteCellStyle.setLeftBorderColor((short) 0);//设置左边框颜色;
//        contentWriteCellStyle.setBorderRight(BorderStyle.THIN);//设置右边框;
//        contentWriteCellStyle.setRightBorderColor((short) 0);//设置右边框颜色;
//        contentWriteCellStyle.setBorderTop(BorderStyle.THIN);//设置顶边框;
//        contentWriteCellStyle.setTopBorderColor((short) 0); ///设置顶边框颜色;

        contentWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);// 水平居中
        contentWriteCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 垂直居中
        contentWriteCellStyle.setWrapped(true); //设置自动换行;

//        contentWriteCellStyle.setShrinkToFit(true);//设置文本收缩至合适

        return contentWriteCellStyle;
    }

}

4、 注解

package com.web.report.annotation;

import com.web.report.enums.HeaderLabelTypeEnum;
import com.web.report.enums.HeaderTypeEnum;

import java.lang.annotation.*;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface TableHeader {
    /**
     * 表头显示名称
     * @return
     */
    String[] label() default {"."};

    /**
     * 正数加在对开头，负数加在结尾
     * @return
     */
    int index() default 1;

    /**
     * 表头类型
     * @return
     */
    HeaderTypeEnum headerType() default HeaderTypeEnum.NORMAL;

    HeaderLabelTypeEnum labelType() default HeaderLabelTypeEnum.NORMAL;


}

 5、枚举

package com.web.report.enums;

public enum HeaderLabelTypeEnum {
    NORMAL, CONFIG
}

package com.web.report.enums;

public enum HeaderTypeEnum {
    NORMAL, FLAT
}

6、各种DTO

（1）TableHeaderConfigDTO 

package com.web.report.dto;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.List;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class TableHeaderConfigDTO {
    private List labels;

    private String value;
}

 （2）WorkReportConditionDTO 

package com.web.report.dto;

import com.web.enums.WorkProcedureResultEnum;
import com.web.report.annotation.TableHeader;
import com.web.report.enums.HeaderLabelTypeEnum;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class WorkReportConditionDTO {

    @TableHeader(labelType = HeaderLabelTypeEnum.CONFIG, index = 1)
    private TableHeaderConfigDTO ConditionDTO;





}

（3）WorkReportDTOT

package com.web.report.dto;

import com.web.report.annotation.TableHeader;
import com.web.report.enums.HeaderTypeEnum;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.List;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class WorkReportDTOT {
    @TableHeader(index = 1, headerType= HeaderTypeEnum.FLAT)
    private List serialNo;

    @TableHeader(index = 2, headerType= HeaderTypeEnum.FLAT)
    private List sequence;

    @TableHeader(index = 3, headerType= HeaderTypeEnum.FLAT)
    private  List bin;

    @TableHeader(index = 4, headerType= HeaderTypeEnum.FLAT)
    private List workReportProcedureDTOS;

}

4、使用

@Component
@Slf4j
public class WorkReportUtilT {



    @Autowired
    private ProjectManageService projectManageService;

    @Autowired
    private WorkManageService workManageService;

    @Autowired
    private WorkResultService WorkResultService;


    private static final Map code2Index = new HashMap<>();

    private static final Map tmMap = new HashMap<>();

    private static final List conditionsList = new ArrayList<>();

    private static final List conditionValueList = new ArrayList<>();

    public void buildReport(WorkManageVO work, String filePath) {
        // 1.初始话报告内容
        XinGanXianWorkReportDTOT workReportDTO = null;
        // 2.判断文件是否存在，如果没有文件那就创建文件并添加表头，表头与数据分开写，防止表头合并
        File file = new File(filePath);
        if (!file.exists()) {
            // 测试结果和头部
            workReportDTO = buildWorkReportDTO(work,  false);
            List> listHead = buildReportHead(workReportDTO);
            //
            ExcelWriter excelWriter = EasyExcel.write(file).build();
            // 合并单元格
            CustomMergeStrategy customMergeStrategy = new CustomMergeStrategy(listHead.size());
            // 只写测试结果头部
            excelWriter.write(new ArrayList<>(),
                    EasyExcel.writerSheet(0).head(listHead).
                            registerWriteHandler(new CustomCellWriteHandler()).
                            registerWriteHandler(customMergeStrategy)
                            .build());
            //这一步很关键，不然文件会损坏
            excelWriter.finish();
            excelWriter.close();
        }
        // 3. 报告内容为空的话，构建
        if(workReportDTO == null){
            workReportDTO = buildWorkReportDTO(work,  false);
        }
        // 4.往文件中追加数据
        List