Java-POI导出EXCEL（动态表头）

1、主要功能

        导出excel，表头有固定的和动态的。动态表头之间不能穿插固定表头。

2、使用方法

        引入下方两个工具类，定义excel固定表头类。调用方法即可。

调用方法：

 ExcelDynamicHeader<MajorNameChangeReport> ledgerSafetyProblemExcelVoExcelUtil = new ExcelDynamicHeader<>(MajorNameChangeReport.class);ledgerSafetyProblemExcelVoExcelUtil.exportExcel(response, resultList,data, "sheet名称", "表格大标题名称");

        解释：response：HttpServletResponse response
                  resultlist：固定表头的数据，即 MajorNameChangeReport 类。
                  data：动态数据，数据形式为：Map<String,List<String>> data。map中的key为表头名
                             称，value为表格数据，注意，数据排序需要和固定表头的数据排序一致。

MajorNameChangeReport 类：

@Data
@Accessors(chain = true)
public class MajorNameChangeReport {private Integer num;@ExcelExport(value = "专业")private String majorName;@ExcelExport(value = "单位")private String depart="项";@ExcelExport(value = "合计",isFirtst = false)private String allCount="0";private String deptId;private Long  majorId;private String deptName;}

3、工具类

ExcelDynamicHeader：其中的log需要手动更改

package com.ruoyi.common.utils.poi.excel;import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.util.IOUtils;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;/*** @author  Mr.Gan* 类描述:  动态表头导出类* createTime:  2024/10/28 9:30*/
public class ExcelDynamicHeader<T> {private static final Logger log = LoggerFactory.getLogger(ExcelDynamicHeader.class);//大标题private String title;//数据对象private List<T> list;//动态数据对象private Map<String,List<String>> dynamicHeader;//实体对象public Class<T> clazz;//表格private Workbook workbook;//sheet页private Sheet sheet;//对象中所有要导入的字段private List<Field> firstFields=new ArrayList<>();private List<Field> lastFields=new ArrayList<>();public ExcelDynamicHeader(Class<T> clazz){this.clazz = clazz;}/*** @author Mr.Gan* 描述：* @param  * @param null:* @return* @date 9:35 2024/10/28*/public void exportExcel(HttpServletResponse response, List<T> list, Map<String,List<String>> dynamicHeader, String sheetName, String title) {// 设置响应内容类型和字符编码response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");response.setCharacterEncoding("UTF-8");//初始化表格initSheet(list, dynamicHeader, sheetName, title);//创建标题createHead();//写数据createData();try{workbook.write(response.getOutputStream());}catch (Exception e){log.error("导出Excel异常{}", e.getMessage());}finally{IOUtils.closeQuietly(workbook);}}//初始化private void initSheet(List<T> list, Map<String, List<String>> dynamicHeader, String sheetName, String title) {workbook=new XSSFWorkbook();sheet = workbook.createSheet(sheetName);this.list=list;this.dynamicHeader=dynamicHeader;this.title=title;}//创建大标题，和表格标题private void createHead(){// 创建单元格样式CellStyle cellStyle = workbook.createCellStyle();cellStyle.setAlignment(HorizontalAlignment.CENTER); // 水平居中cellStyle.setVerticalAlignment(VerticalAlignment.CENTER); // 垂直居中//创建表格标题Row row = sheet.createRow(1);Field[] declaredFields = clazz.getDeclaredFields();Integer cellIndex=0;//固定标题前部分for (Field declaredField : declaredFields) {if (declaredField.isAnnotationPresent(ExcelExport.class)){declaredField.setAccessible(true);ExcelExport attr = declaredField.getAnnotation(ExcelExport.class);if(attr.isFirtst()){row.createCell(cellIndex).setCellValue(attr.value());row.getCell(cellIndex).setCellStyle(cellStyle);cellIndex++;firstFields.add(declaredField);}else{lastFields.add(declaredField);}}}//动态标题部分for (String s : dynamicHeader.keySet()) {row.createCell(cellIndex).setCellValue(s);row.getCell(cellIndex).setCellStyle(cellStyle);cellIndex++;}//固定标题后部分for (Field declaredField : lastFields) {if (declaredField.isAnnotationPresent(ExcelExport.class)){declaredField.setAccessible(true);ExcelExport attr = declaredField.getAnnotation(ExcelExport.class);row.createCell(cellIndex).setCellValue(attr.value());row.getCell(cellIndex).setCellStyle(cellStyle);cellIndex++;}}//创建大标题Row row1 = sheet.createRow(0);row1.createCell(0).setCellValue(title);CellRangeAddress cellRangeAddress = new CellRangeAddress(0, // 第一行索引0, // 最后一行索引0, // 第一列索引cellIndex-1  // 最后一列索引);sheet.addMergedRegion(cellRangeAddress);//设置居中row1.getCell(0).setCellStyle(cellStyle);}private void createData(){Integer rowidex=2;try {for (T t : list) {int cellIndex=0;Row row = sheet.createRow(rowidex);//添加头数据for (Field firstField : firstFields) {firstField.setAccessible(true);Object value = firstField.get(t);row.createCell(cellIndex).setCellValue(value.toString());cellIndex++;}//动态数据for (String s : dynamicHeader.keySet()) {row.createCell(cellIndex).setCellValue(dynamicHeader.get(s).get(rowidex-2));cellIndex++;}//添加尾数据for (Field firstField : lastFields) {firstField.setAccessible(true);Object value = firstField.get(t);row.createCell(cellIndex).setCellValue(value.toString());cellIndex++;}rowidex++;}} catch (IllegalAccessException e) {throw new RuntimeException(e);}}}

ExcelExport类：

package com.ruoyi.common.utils.poi.excel;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelExport {/** 字段名称 */String value();//此标题是否在动态标题前boolean isFirtst() default true;
}