实现功能 --批量导出excel 文件，配置一个sheet多少条数据，根据查询数据量的多少确定生成几个sheet页。
pom 文件导入ExcelUtils工具包，依赖于poi包。
<!-- /artifact/org.hellojavaer/poi-excel-utils -->
<dependency>
<groupId>org.hellojavaer</groupId>
<artifactId>poi-excel-utils</artifactId>
<version>1.1.0-beta</version>
</dependency>
找到ExcelUtils工具包，重构代码。
package cn.enn.chaoscloud.master.utils;
import com.lkx.util.StringUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DateUtil;
import org.springframework.beans.BeanUtils;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
@Slf4j
public class ExcelUtils implements Serializable {
private static final long serialVersionUID = 1L;
/**
* getMap:(将传进来的表头和表头对应的属性存进Map集合，表头字段为key,属性为value)
*
* @author likaixuan
* @param
* : String keyValue = "手机名称:phoneName,颜色:color,售价:price";
* @return
* @since JDK 1.7
*/
public static Map<String, String> getMap(String keyValue) {
Map<String, String> map = new HashMap<String, String>();
if (keyValue != null) {
String[] str = keyValue.split(",");
for (String element : str) {
String[] str2 = element.split(":");
map.put(str2[0], str2[1]);
}
}
return map;
}
/**
* @author likaixuan
* @param
* @return List
* @Date 5月9日 21:42:24
* @since JDK 1.7
*/
public static List<String> getList(String keyValue) {
List<String> list = new ArrayList<String>();
if (keyValue != null) {
String[] str = keyValue.split(",");
for (String element : str) {
String[] str2 = element.split(":");
list.add(str2[0]);
}
}
return list;
}
/**
* setter:(反射的set方法给属性赋值)
*
* @author likaixuan
* @param obj
* 具体的类
* @param att
* 类的属性
* @param value
* 赋予属性的值
* @param type
* 属性是哪种类型 比如:String double boolean等类型
* @throws Exception
* @since JDK 1.7
*/
public static void setter(Object obj, String att, Object value, Class<?> type, int row, int col, Object key)
throws Exception {
try {
Method method = obj.getClass().getMethod("set" + StringUtil.toUpperCaseFirstOne(att), type);
method.invoke(obj, value);
} catch (Exception e) {
throw new Exception("第" + (row + 1) + " 行 " + (col + 1) + "列 属性：" + key + " 赋值异常 " + e);
}
}
/**
* getAttrVal:(反射的get方法得到属性值)
*
* @author likaixuan
* @param obj
* 具体的类
* @param att
* 类的属性
* @param
*
* @param type
* 属性是哪种类型 比如:String double boolean等类型
* @throws Exception
* @since JDK 1.7
*/
public static Object getAttrVal(Object obj, String att, Class<?> type) throws Exception {
try {
Method method = obj.getClass().getMethod("get" + StringUtil.toUpperCaseFirstOne(att));
Object value = new Object();
value = method.invoke(obj);
return value;
} catch (Exception e) {
log.error(e.getMessage(), e);
return null;
}
}
/**
* getValue:(得到Excel列的值)
*
* @author likaixuan
* @param
* @return
* @throws Exception
* @since JDK 1.7
*/
public static void getValue(Cell cell, Object obj, String attr, Class attrType, int row, int col, Object key)
throws Exception {
Object val = null;
if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN) {
val = cell.getBooleanCellValue();
} else if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
if (DateUtil.isCellDateFormatted(cell)) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try {
if (attrType == String.class) {
val = sdf.format(DateUtil.getJavaDate(cell.getNumericCellValue()));
} else {
val = dateConvertFormat(sdf.format(DateUtil.getJavaDate(cell.getNumericCellValue())));
}
} catch (ParseException e) {
throw new Exception("第" + (row + 1) + " 行 " + (col + 1) + "列 属性：" + key + " 日期格式转换错误 ");
}
} else {
if (attrType == String.class) {
cell.setCellType(Cell.CELL_TYPE_STRING);
val = cell.getStringCellValue();
} else if (attrType == BigDecimal.class) {
val = new BigDecimal(cell.getNumericCellValue());
} else if (attrType == long.class) {
val = (long) cell.getNumericCellValue();
} else if (attrType == Double.class) {
val = cell.getNumericCellValue();
} else if (attrType == Float.class) {
val = (float) cell.getNumericCellValue();
} else if (attrType == int.class || attrType == Integer.class) {
val = (int) cell.getNumericCellValue();
} else if (attrType == Short.class) {
val = (short) cell.getNumericCellValue();
} else {
val = cell.getNumericCellValue();
}
}
} else if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
val = cell.getStringCellValue();
}
setter(obj, attr, val, attrType, row, col, key);
}
/**
* exportExcel:(导出Excel)
*
* @author likaixuan
* @param
* @return
* @throws Exception
* @since JDK 1.7
*/
public static void exportExcel(HSSFWorkbook wb,OutputStream outputStream, String keyValue, List<?> list, String classPath,int sheetNum,int pageNum)
throws Exception {
Map<String, String> map = getMap(keyValue);
List<String> keyList = getList(keyValue);
Class<?> demo = null;
demo = Class.forName(classPath);
Object obj = demo.newInstance();
// 建立新的sheet对象（excel的表单）
String sheetName = "sheet"+String.valueOf(sheetNum);
HSSFSheet sheet = wb.createSheet(sheetName);
// 声明样式
HSSFCellStyle style = wb.createCellStyle();
// 居中显示
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
// 在sheet里创建第一行为表头，参数为行索引(excel的行)，可以是0～65535之间的任何一个
HSSFRow rowHeader = sheet.createRow(0);
// 创建单元格并设置单元格内容
// 存储属性信息
Map<String, String> attMap = new HashMap();
int index = 0;
for (String key : keyList) {
rowHeader.createCell(index).setCellValue(key);
attMap.put(Integer.toString(index), map.get(key).toString());
index++;
}
// 在sheet里创建表头下的数据
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i));
HSSFRow row = sheet.createRow(i + 1);
for (int j = 0; j < map.size(); j++) {
Class<?> attrType = BeanUtils.findPropertyType(attMap.get(Integer.toString(j)),
new Class[] { obj.getClass() });
Object value = getAttrVal(list.get(i), attMap.get(Integer.toString(j)), attrType);
if (null == value) {
value = "";
}
row.createCell(j).setCellValue(value.toString());
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
}
}
// 输出Excel文件
try {
if(sheetNum == pageNum || pageNum == 0){
wb.write(outputStream);
outputStream.close();
}
} catch (FileNotFoundException e) {
throw new FileNotFoundException("导出失败！" + e);
} catch (IOException e) {
throw new IOException("导出失败！" + e);
}
}
/**
* String类型日期转为Date类型
*
* @param dateStr
* @return
* @throws ParseException
* @throws Exception
*/
public static Date dateConvertFormat(String dateStr) throws ParseException {
Date date = new Date();
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
date = format.parse(dateStr);
return date;
}
}
调用封装工具类
public static final int page_size = 10000;
@PostMapping("queryUnusedGasListExcel")
public byte[] queryUnusedGasListExcel(@RequestBody UnusedGasDTO unusedGasDTO) throws Exception{
byte[] bytes = null;
try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream()){
int list_count = unusedGasService.findCountList(unusedGasDTO);
// 根据行数求数据提取次数
int export_times = list_count % page_size > 0 ? list_count / page_size
+ 1 : list_count / page_size;
// 创建HSSFWorkbook对象(excel的文档对象)
HSSFWorkbook wb = new HSSFWorkbook();
for (int j = 0; j < export_times; j++) {
unusedGasDTO.setPositionNum(j*page_size);
unusedGasDTO.setShowNum(page_size);
List<UnusedGasVO> list = unusedGasService.downLoadByList(unusedGasDTO);
int len = list.size() < page_size ? list.size() : page_size;
String keyValue = "客户名称:customerName,房产名称:houseName,表钢号:meterCode,余额(元):balance,表底数:meterBase,未用气天数:unusedGasDays,客户类型编码:customerCode,联系方式:customerTel,表型名称:metersTypeName,合约号:contractNum," +
"集团id:groupId,集团编码:groupName,公司id:companyId,公司编码:companyCode,公司名称:companyName," +
"客户电话:customerTel,房产编码:houseCode,表型编码:meterType,未用气天数时间:unusedGasTime";
//HSSFWorkbook ;j+1 sheet当前页; export_times sheet总页数
/**
* HSSFWorkbook
* outputStream流
* 根据反射获取实体类，并且赋值
* list 查询到的实体集合
* classPath list 中实体的路径，反射用到
* j+1 要写入sheet的页数
* 重新查询数据的次数
*/
ExcelUtils.exportExcel(wb,byteArrayOutputStream, keyValue, list, "cn.enn.chaoscloud.domain.archives.meter.vo.UnusedGasVO", j+1,export_times);
}
bytes = byteArrayOutputStream.toByteArray();
}catch (Exception e){
log.error(e.getMessage(), e);
}
return bytes;
}
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