如果需要导出复杂的单元格，合并单元格，请查看
Java中导出Excel，合并单元格，简单上手_SUMMERENT的博客-CSDN博客
目录
3、编写ExportUtil导出数据工具，支持xlsx和csv两种
1、引入maven依赖
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>5.3.8</version>
</dependency>
<dependency>
<groupId>cn.jimmyshi</groupId>
<artifactId>bean-query</artifactId>
<version>1.1.5</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>注意：下面如果有报错，请查看导入的maven依赖
2、 编写ExportExcelVo
@Data
public class ExportExcelVo {
private String headOne;
private String headTwoCome;
private String headTwoOn;
private String headThreeCome;
private String headThreeOn;
private String headFourCome;
private String headFourOn;
private String headFiveCome;
private String headFiveOn;
}
3、编写ExportUtil导出数据工具，支持xlsx和csv两种
import cn.hutool.core.io.IoUtil;
import cn.hutool.poi.excel.ExcelUtil;
import cn.hutool.poi.excel.ExcelWriter;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
import org.apache.commons.io.FilenameUtils;
import org.springframework.util.CollectionUtils;
import cn.jimmyshi.beanquery.BeanQuery;
import springboot.redis.demo.exception.MyRuntimeException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.util.Collection;
import java.util.List;
import java.util.Map;
/**
* @Description: 导出数据工具，支持xlsx和csv两种
* @Title: ExportUtil
*/
@Slf4j
public class ExportUtil {
/**
*
* @param dataList 导出数据列表
* @param fieldMap 导出的数据字段，key为对象字段名称，value为标题名称
* @param fileName 导出文件名
* @return void
* @throws IOException 文件操作失败
*/
public static <T> void doExport(Collection<T> dataList, Map<String,String> fieldMap,String fileName) throws IOException{
if (CollectionUtils.isEmpty(dataList)){
return;
}
StringBuilder sb = new StringBuilder(128);
for (Map.Entry<String,String> e: fieldMap.entrySet()) {
sb.append(e.getKey()).append(" as ").append(e.getValue()).append(", ");
}
//去掉末尾空格
String fieldString = sb.substring(0,sb.length() - 2);
//写出数据到excel格式的输出流,BeanQuery 是一个把对象转换为Map的Java工具库
List<Map<String,Object>> resultList = BeanQuery.select(fieldString).executeFrom(dataList);
构建HTTP输出流参数
HttpServletResponse response = ContextUtil.getHttpResponse();
response.setHeader("content-type", "application/octet-stream");
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
if ("xlsx".equals(FilenameUtils.getExtension(fileName))) {
ServletOutputStream out = response.getOutputStream();
ExcelWriter writer = ExcelUtil.getWriter(true);
writer.setRowHeight(-1, 30);
writer.setColumnWidth(-1, 30);
writer.setColumnWidth(1, 20);
writer.write(resultList);
writer.flush(out);
writer.close();
IoUtil.close(out);
} else if ("csv".equals(FilenameUtils.getExtension(fileName))) {
Collection<String> headerList = fieldMap.values();
String[] headerArray = new String[headerList.size()];
headerList.toArray(headerArray);
CSVFormat format = CSVFormat.DEFAULT.withHeader(headerArray);
response.setCharacterEncoding(StandardCharsets.UTF_8.name());
try (Writer out = response.getWriter(); CSVPrinter printer = new CSVPrinter(out, format)) {
for (Map<String, Object> o : resultList) {
for (Map.Entry<String, Object> entry : o.entrySet()) {
printer.print(entry.getValue());
}
printer.println();
}
printer.flush();
} catch (Exception e) {
log.error("Failed to call ExportUtil.doExport", e);
}
} else {
throw new MyRuntimeException("导出文件类型不支持！");
}
}
}
ContextUtil 类
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletResponse;
public class ContextUtil {
public static HttpServletResponse getHttpResponse() {
return ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getResponse();
}
}4、编写ExcelService层，准备数据
import java.util.ArrayList;
import java.util.List;
public class ExcelService {
public static List<ExportExcelVo> getExportData() {
ExportExcelVo excelVo = new ExportExcelVo();
List<ExportExcelVo> list = new ArrayList<>();
for (int i = 0; i < 3; i++) {
excelVo.setHeadOne("AAA");
excelVo.setHeadTwoCome("BBB");
excelVo.setHeadTwoOn("CCC");
excelVo.setHeadThreeCome("DDD");
excelVo.setHeadThreeOn("EEE");
excelVo.setHeadFourCome("FFF");
excelVo.setHeadFourOn("GGG");
excelVo.setHeadFiveCome("HHH");
excelVo.setHeadFiveOn("III");
list.add(excelVo);
}
return list;
}
}
5、编写controller层，调用接口
@RestController
public class alibaba {
@GetMapping("/exportA")
public void exportA(HttpServletResponse response) throws Exception {
List<ExportExcelVo> data = ExcelService.getExportData();
// 构建导出的map
Map<String,String> headerMap = new LinkedHashMap<>(21);
headerMap.put("headOne","单元格一");
headerMap.put("headTwoCome", "单元格二");
headerMap.put("headTwoOn", "单元格三");
headerMap.put("headThreeCome", "单元格四");
headerMap.put("headThreeOn", "单元格五");
headerMap.put("headFourCome", "单元格六");
headerMap.put("headFourOn", "单元格七");
headerMap.put("headFiveCome", "单元格八");
headerMap.put("headFiveOn", "单元格九");
ExportUtil.doExport(data,headerMap,"测试.xlsx");
}
}
6、测试导出
在浏览器地址栏中访问：http://localhost:项目端口号/exportA
如果需要导出复杂的单元格，合并单元格，请查看