java导出excel设置列宽 java导出excel自适应列宽

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编程小匠人之魂 2023-07-28 07:52:01

文章标签 java导出excel设置列宽 python pandas 开发语言 java 文章分类 Java 后端开发

1、自适应列宽实现类

2、单元格样式实现类

3、导出的时候，特殊数据类型，需要设置转换类，不然注解导出方式会报错

注解使用方式

日期转换类

4、web导出excel(将excel数据写入到response输出流中)

本博客不是写给小白的，小白可以去官网看案例：写Excel | Easy Excel

1、自适应列宽实现类

package com.xinba.statistical.rules.base.utils.excel;

import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.poi.ss.usermodel.Cell;

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

public class ExcelCellWidthStyleStrategy extends AbstractColumnWidthStyleStrategy {
    // 可以根据这里的最大宽度，按自己需要进行调整,搭配单元格样式实现类中的，自动换行，效果更好
    private static final int MAX_COLUMN_WIDTH = 50;
    private  Map<Integer, Map<Integer, Integer>> CACHE = new HashMap(8);

    @Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
        if (needSetWidth) {
            Map<Integer, Integer> maxColumnWidthMap = (Map)CACHE.get(writeSheetHolder.getSheetNo());
            if (maxColumnWidthMap == null) {
                maxColumnWidthMap = new HashMap(16);
                CACHE.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
            }

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

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

            }
        }
    }

    private Integer dataLength(List<CellData> cellDataList, Cell cell, Boolean isHead) {
        if (isHead) {
            return cell.getStringCellValue().getBytes().length;
        } else {
            CellData cellData = (CellData)cellDataList.get(0);
            CellDataTypeEnum type = cellData.getType();
            if (type == null) {
                return -1;
            } else {
                switch(type) {
                    case STRING:
                        return cellData.getStringValue().getBytes().length;
                    case BOOLEAN:
                        return cellData.getBooleanValue().toString().getBytes().length;
                    case NUMBER:
                        return cellData.getNumberValue().toString().getBytes().length;
                    default:
                        return -1;
                }
            }
        }
    }

}

2、单元格样式实现类

package com.xinba.statistical.rules.base.utils.excel;

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

public class StyleUtils {


    private static final String[] _formats = new String[]{
            "General",
            "0",
            "0.00",
            "#,##0",
            "#,##0.00",
            "\"$\"#,##0_);(\"$\"#,##0)",
            "\"$\"#,##0_);[Red](\"$\"#,##0)",
            "\"$\"#,##0.00_);(\"$\"#,##0.00)",
            "\"$\"#,##0.00_);[Red](\"$\"#,##0.00)",
            "0%", "0.00%", "0.00E+00",
            "# ?/?", "# ??/??",
            "m/d/yy", "d-mmm-yy",
            "d-mmm", "mmm-yy",
            "h:mm AM/PM",
            "h:mm:ss AM/PM",
            "h:mm", "h:mm:ss",
            "m/d/yy h:mm",
            "reserved-0x17",
            "reserved-0x18",
            "reserved-0x19",
            "reserved-0x1A",
            "reserved-0x1B",
            "reserved-0x1C",
            "reserved-0x1D",
            "reserved-0x1E",
            "reserved-0x1F",
            "reserved-0x20",
            "reserved-0x21",
            "reserved-0x22",
            "reserved-0x23",
            "reserved-0x24",
            "#,##0_);(#,##0)",
            "#,##0_);[Red](#,##0)",
            "#,##0.00_);(#,##0.00)",
            "#,##0.00_);[Red](#,##0.00)",
            "_(* #,##0_);_(* (#,##0);_(* \"-\"_);_(@_)",
            "_(\"$\"* #,##0_);_(\"$\"* (#,##0);_(\"$\"* \"-\"_);_(@_)",
            "_(* #,##0.00_);_(* (#,##0.00);_(* \"-\"??_);_(@_)",
            "_(\"$\"* #,##0.00_);_(\"$\"* (#,##0.00);_(\"$\"* \"-\"??_);_(@_)",
            "mm:ss",
            "[h]:mm:ss",
            "mm:ss.0",
            "##0.0E+0",
            "@" // 文本格式
    };


    /**
     * 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)10);//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) 9);//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.setDataFormat((short)49);//设置单元格格式是：文本格式，方式长数字文本科学计数法

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

        return contentWriteCellStyle;
    }

}

3、导出的时候，特殊数据类型，需要设置转换类，不然注解导出方式会报错

注解使用方式

@ExcelProperty(value = "进站日期",  converter = LocalDateTimeConverter.class, index = 20)
private LocalDateTime arriveTime;

日期转换类

package com.xinba.statistical.rules.base.utils.excel;

import com.alibaba.excel.converters.Converter;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.GlobalConfiguration;
import com.alibaba.excel.metadata.property.DateTimeFormatProperty;
import com.alibaba.excel.metadata.property.ExcelContentProperty;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class LocalDateTimeConverter implements Converter<LocalDateTime> {

	private static final String DEFAULT_DATETIME_FORMAT = "yyyy-MM-dd HH:mm:ss";

	@Override
	public Class<LocalDateTime> supportJavaTypeKey() {
		return LocalDateTime.class;
	}

	@Override
	public CellDataTypeEnum supportExcelTypeKey() {
		return CellDataTypeEnum.STRING;
	}

	@Override
	public LocalDateTime convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,
										   GlobalConfiguration globalConfiguration) {
		DateTimeFormatProperty dateTimeFormatProperty = contentProperty.getDateTimeFormatProperty();
		String dateTimeFormatPattern = DEFAULT_DATETIME_FORMAT;
		if(null != dateTimeFormatProperty){
			dateTimeFormatPattern = dateTimeFormatProperty.getFormat();
		}
		return LocalDateTime.parse(cellData.getStringValue(), DateTimeFormatter.ofPattern(dateTimeFormatPattern));
	}

	@Override
	public CellData<String> convertToExcelData(LocalDateTime value, ExcelContentProperty contentProperty,
	                                           GlobalConfiguration globalConfiguration) {
		DateTimeFormatProperty dateTimeFormatProperty = contentProperty.getDateTimeFormatProperty();
		String dateTimeFormatPattern = DEFAULT_DATETIME_FORMAT;
		if(null != dateTimeFormatProperty){
			dateTimeFormatPattern = dateTimeFormatProperty.getFormat();
		}
		return new CellData<>(value.format(DateTimeFormatter.ofPattern(dateTimeFormatPattern)));
	}

}

4、web导出excel(将excel数据写入到response输出流中)

// 直接用浏览器或者用postman
        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 = String.format("文件名称"+System.currentTimeMillis(), taskCode);
        fileName = URLEncoder.encode(fileName, "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");

        OutputStream out = response.getOutputStream();
        // 设置单元格样式
        HorizontalCellStyleStrategy horizontalCellStyleStrategy =
                new HorizontalCellStyleStrategy(StyleUtils.getHeadStyle(), StyleUtils.getContentStyle());
        // 列宽策略设置
        ExcelCellWidthStyleStrategy widthStyleStrategy = new ExcelCellWidthStyleStrategy();
        ExcelWriter excelWriter = EasyExcel.write(out)
                .registerWriteHandler(horizontalCellStyleStrategy)
                .registerWriteHandler(widthStyleStrategy)
                .build();
        // 总体统计 sheet
        WriteSheet totalSheet = EasyExcel.writerSheet(0, "总体统计").head(StatisticsAnalyseDivisorVo.class).build();
        excelWriter.write(total,totalSheet);
        // web导出，这里必须要有这个finish，不然导出的文件是空的，官方文档的案例没写
        excelWriter.finish();

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