常用的EasyExcel表格处理-2（动态合并、自适应宽高）
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1、动态合并单元格
此处主要根据自定义处理类ExcelFillCellMergeStrategy进行处理，具体内容可看代码注释。
1.1 前端调用controller
@PostMapping("/download/template")
public void toDoExport(HttpServletResponse response) {
// 设置模拟表头（此处为多表头，也可以传入单表头）
List<List<String>> headList = new ArrayList<>();
List<String> heads1 = new ArrayList<>();
heads1.add("总表头");
heads1.add("表头1");
headList.add(heads1);
List<String> heads2 = new ArrayList<>();
heads2.add("总表头");
heads2.add("表头2");
headList.add(heads2);
List<String> heads3 = new ArrayList<>();
heads3.add("总表头");
heads3.add("表头3");
headList.add(heads3);
List<String> heads4 = new ArrayList<>();
heads4.add("总表头");
heads4.add("表头4");
headList.add(heads4);
// 设置模拟内容
List<List<String>> data = new ArrayList<>();
List<String> data1 = new ArrayList<>(); // 第1行的内容
data1.add("内容1");
data1.add("内容1-2");
data1.add("内容3");
data1.add("内容4");
List<String> data2 = new ArrayList<>();// 第2行的内容
data2.add("内容1");
data2.add("内容2-2");
data2.add("内容3");
data2.add("内容4");
data.add(data1);
data.add(data2);
try {
response.setContentType("application/vnd.ms-excel");
response.setCharacterEncoding("utf-8");
// 防止中文乱码
String fileName = URLEncoder.encode("导入模板名称", "UTF-8");
response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
ServletOutputStream outputStream = response.getOutputStream();
ExcelWriter writer = EasyExcel.write(outputStream).build();
WriteSheet sheet = EasyExcel.writerSheet(0).needHead(Boolean.FALSE).sheetName("sheet页名称").build();
WriteTable table1 = EasyExcel.writerTable(1).head(headList)
// 设置只合并第1、2、3列，其余不合并
.registerWriteHandler(new ExcelFillCellMergeStrategy(1,new int[]{0,1,2}))
.needHead(Boolean.TRUE).build();
writer.write(data, sheet, table1); // data
writer.finish();
} catch (IOException e) {
e.printStackTrace();
}
}
1.2 批注渲染处理类（ExcelFillCellMergeStrategy）
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.handler.CellWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import lombok.Data;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellRangeAddress;
import java.util.List;
@Data
public class ExcelFillCellMergeStrategy implements CellWriteHandler {
/**
* 合并字段的下标，如第一到五列new int[]{0,1,2,3,4}
*/
private int[] mergeColumnIndex;
/**
* 从第几行开始合并，如果表头占两行，这个数字就是2
*/
private int mergeRowIndex;
public ExcelFillCellMergeStrategy() {
}
public ExcelFillCellMergeStrategy(int mergeRowIndex, int[] mergeColumnIndex) {
this.mergeRowIndex = mergeRowIndex;
this.mergeColumnIndex = mergeColumnIndex;
}
@Override
public void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row,
Head head, Integer integer, Integer integer1, Boolean aBoolean) {
}
@Override
public void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell,
Head head, Integer integer, Boolean aBoolean) {
}
@Override
public void afterCellDataConverted(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder,
CellData cellData, Cell cell, Head head, Integer integer, Boolean aBoolean) {
}
@Override
public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder,
List<CellData> list, Cell cell, Head head, Integer integer, Boolean aBoolean) {
//当前行
int curRowIndex = cell.getRowIndex();
//当前列
int curColIndex = cell.getColumnIndex();
if (curRowIndex > mergeRowIndex) {
for (int i = 0; i < mergeColumnIndex.length; i++) {
if (curColIndex == mergeColumnIndex[i]) {
mergeWithPrevRow(writeSheetHolder, cell, curRowIndex, curColIndex);
break;
}
}
}
}
private void mergeWithPrevRow(WriteSheetHolder writeSheetHolder, Cell cell, int curRowIndex, int curColIndex) {
//获取当前行的当前列的数据和上一行的当前列列数据，通过上一行数据是否相同进行合并
Object curData = cell.getCellTypeEnum() == CellType.STRING ? cell.getStringCellValue() :
cell.getNumericCellValue();
Cell preCell = cell.getSheet().getRow(curRowIndex - 1).getCell(curColIndex);
Object preData = preCell.getCellTypeEnum() == CellType.STRING ? preCell.getStringCellValue() :preCell.getNumericCellValue();
// 比较当前行的第一列的单元格与上一行是否相同，相同合并当前单元格与上一行
if (curData.equals(preData)) {
Sheet sheet = writeSheetHolder.getSheet();
List<CellRangeAddress> mergeRegions = sheet.getMergedRegions();
boolean isMerged = false;
for (int i = 0; i < mergeRegions.size() && !isMerged; i++) {
CellRangeAddress cellRangeAddr = mergeRegions.get(i);
// 若上一个单元格已经被合并，则先移出原有的合并单元，再重新添加合并单元
if (cellRangeAddr.isInRange(curRowIndex - 1, curColIndex)) {
sheet.removeMergedRegion(i);
cellRangeAddr.setLastRow(curRowIndex);
sheet.addMergedRegion(cellRangeAddr);
isMerged = true;
}
}
// 若上一个单元格未被合并，则新增合并单元
if (!isMerged) {
CellRangeAddress cellRangeAddress = new CellRangeAddress(curRowIndex - 1, curRowIndex, curColIndex,
curColIndex);
sheet.addMergedRegion(cellRangeAddress);
}
}
}
}
1.3 效果
通过传递参数控制了只合并前3列，第4列不合并，效果如图
2、自适应列宽、行高
2.1 自适应列宽
此处主要根据自定义处理类CustomCellWriteWeightConfig进行处理。
public class CustomCellWriteWeightConfig extends AbstractColumnWidthStyleStrategy {
private Map<Integer, Map<Integer, Integer>> CACHE = new HashMap<>();
@Override
protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<CellData> cellDataList, Cell cell, Head head, Integer integer, Boolean isHead) {
boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
if (needSetWidth) {
Map<Integer, Integer> maxColumnWidthMap = CACHE.get(writeSheetHolder.getSheetNo());
if (maxColumnWidthMap == null) {
maxColumnWidthMap = new HashMap<>();
CACHE.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
}
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);
}
}
}
}
/**
* 计算长度
* @param cellDataList
* @param cell
* @param isHead
* @return
*/
private Integer dataLength(List<CellData> 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）
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 自适应行高
此处主要根据自定义处理类CustomCellWriteHeightConfig进行处理。
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
Integer maxHeight = 1;
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
switch (cell.getCellTypeEnum()) {
case STRING:
if (cell.getStringCellValue().indexOf("\n") != -1) {
int length = cell.getStringCellValue().split("\n").length;
maxHeight = Math.max(maxHeight, length);
}
break;
default:
break;
}
}
row.setHeight((short) (maxHeight * DEFAULT_HEIGHT));
}
}
2.3 注册器处理
EasyExcel.registerWriteHandler(new CustomCellWriteWeightConfig())
.registerWriteHandler(new CustomCellWriteHeightConfig());