EasyExcel导出列表

通过easyexcel导出列表数据

根据列表内容自适应宽高。

文件名冲突，修改文件名递增设置。

依赖

            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>easyexcel</artifactId>
                <version>${easyexcel.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>easyexcel-core</artifactId>
                <version>${easyexcel.version}</version>
                <scope>compile</scope>
            </dependency>

  <easyexcel.version>3.3.2</easyexcel.version>

 具体实现

 public void export(HttpServletResponse response) {
  
       try {
            String fileName = "服务发布.xlsx";
            //解决文件冲突问题
            String newFilePath = getUniqueFilePath(fileName);
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setCharacterEncoding("utf-8");
            String name = URLEncoder.encode(newFilePath, StandardCharsets.UTF_8).replaceAll("\\+", "%20");
            response.setHeader("Content-disposition", "attachment;filename*=" + name);
            // 写入Excel文件
            EasyExcel.write(response.getOutputStream(), ApiExcel.class)
                      //自带的自动列宽
                     .registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
                     .registerWriteHandler(new CustomCellWriteWidthConfig())
                     .sheet("服务发布列表").doWrite(apiExcels);
        } catch (IOException e) {
            log.error("导出服务发布数据失败！{}", e.getMessage());
            throw new RuntimeException("导出服务发布数据失败！");
        }
    }

 判断文件是否存在。

 private static String getUniqueFilePath(String baseFileName) {
        File file = new File(baseFileName);
        int counter = 1;
        
        while (file.exists()) {
            String newFileName = String.format("%s(%d).xlsx", baseFileName.replace(".xlsx", ""), counter);
            file = new File(newFileName);
            counter++;
        }
        
        return file.getAbsolutePath();
    }

自适应列宽类

package com.cait.fm.console.common;

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

/**
 * @author: jg
 * @date: 2024-12-06
 * @description:
 */
public class CustomCellWriteWidthConfig extends AbstractColumnWidthStyleStrategy {
    
    private final 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 || !cellDataList.isEmpty();
        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 > 10 && columnWidth <= 20) {
                    columnWidth = 20;
                } else if (columnWidth <= 10) {
                    columnWidth = 10;
                }
                Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());
                if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
                    maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);
                    Sheet sheet = writeSheetHolder.getSheet();
                    sheet.setColumnWidth(cell.getColumnIndex(), 256 * columnWidth + 184);
                }
            }
        }
    }
    
    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:
                        // 换行符（数据需要提前解析好）
                        String stringValue = cellData.getStringValue();
                        if (stringValue.contains("\n")) {
                            int index = stringValue.indexOf("\n");
                            return index != -1 ? stringValue.substring(0, index).getBytes().length + 1 : stringValue.getBytes().length + 1;
                        } else if (stringValue.contains("(")) {
                            return stringValue.getBytes().length;
                        } else {
                            return stringValue.getBytes().length;
                        }
                    case BOOLEAN:
                        return cellData.getBooleanValue().toString().getBytes().length;
                    case NUMBER:
                        return cellData.getNumberValue().toString().getBytes().length;
                    default:
                        return -1;
                }
            }
        }
    }
    
}

 自适应行高

public class CustomCellWriteHeightConfig extends AbstractRowHeightStyleStrategy {

    /**
     * 默认高度
     */
    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;
        }
        // 默认为 1 行高度
        int maxHeight = 1;
        while (cellIterator.hasNext()) {
            Cell cell = cellIterator.next();
            if (cell.getCellType() == CellType.STRING) {
                String value = cell.getStringCellValue();
                for (int i = 0; i < value.length(); i += 10) {
                    if (i + 10 < value.length()) {
                        value = value.substring(0, i) + "\n" + value.substring(i, i + 10) + value.substring(i + 10);
                    } else {
                        value = value.substring(0, i) + "\n" + value.substring(i);
                    }
                }
                if (value.contains("\n")) {
                    int length = value.split("\n").length;
                    maxHeight = Math.max(maxHeight, length);
                }
            }
        }
        row.setHeight((short) (maxHeight * DEFAULT_HEIGHT));
    }

    @Override
    public void afterRowDispose(RowWriteHandlerContext context) {
        if (context.getHead() != null) {
            if(ObjectUtils.isEmpty(context.getRelativeRowIndex())){
                return;
            }
            if (Boolean.TRUE.equals(context.getHead())) {
                this.setHeadColumnHeight(context.getRow(), context.getRelativeRowIndex());
            } else {
                this.setContentColumnHeight(context.getRow(), context.getRelativeRowIndex());
            }

        }
    }
}