用于批量数据的导入和导出。POI和EasyExcel都是可以 *** 作excel的第三方组件。
POI依赖
数据单行写入org.apache.poi poi5.2.0 org.apache.poi poi-ooxml5.2.0 joda-time joda-time2.10.13 junit junit4.13.2 test
package cn.zjq;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.joda.time.DateTime;
import java.io.FileOutputStream;
import java.io.IOException;
public class ExcelWriteTest {
private static String Path = "D:/CODE/poi-easyEXCEL/";
public static void main(String[] args) throws IOException {
// 创建一个工作簿 03版本
Workbook workbook = new HSSFWorkbook();//07 XSSWorkbook
// 创建一个工资表
Sheet sheet = workbook.createSheet("biao1");
// 创建第一行
Row row1 = sheet.createRow(0);
// 创建单元格
Cell cell = row1.createCell(0);//(1,1)
Cell cell1 = row1.createCell(1);//(1,2)
// 设置值
cell.setCellValue("今日新增");
cell1.setCellValue(666);
// 创建第二行
Row row2 = sheet.createRow(1);
// 创建单元格
Cell cell2 = row2.createCell(1);
String time = new DateTime().toString("yyyy-MM-dd HH:mm:ss");
cell2.setCellValue(time);
// 生成表(IO)
FileOutputStream fileOutputStream = new FileOutputStream(Path + "表1.xls");//07 xlsx
workbook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("生成完毕");
}
}
数据批量导入
HSSF最多只能处理65536行，多了会抛出异常。但是因为写入内存再读入磁盘因此速度较快。
XSSF速度较慢，消耗内存，可写入较大的文件。
03版
@Test
void testBigData() throws IOException {
long begin = System.currentTimeMillis();
HSSFWorkbook workbook = new HSSFWorkbook();
HSSFSheet sheet = workbook.createSheet();
for (int rowNumber = 0; rowNumber <65536 ; rowNumber++) {
HSSFRow row = sheet.createRow(rowNumber);
for (int cellNumber = 0; cellNumber < 10; cellNumber++) {
HSSFCell cell = row.createCell(cellNumber);
cell.setCellValue(cellNumber);
}
}
FileOutputStream fileOutputStream = new FileOutputStream(Path + "大数据03.xls");//07 xlsx
workbook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("生成完毕");
long end = System.currentTimeMillis();
System.out.println((double)(end - begin)/1000);
}
行数超过65536就会报异常,但是速度较快。
@Test
void testBigData07() throws IOException {
long begin = System.currentTimeMillis();
XSSFWorkbook workbook = new XSSFWorkbook();
XSSFSheet sheet = workbook.createSheet();
for (int rowNumber = 0; rowNumber <655370 ; rowNumber++) {
XSSFRow row = sheet.createRow(rowNumber);
for (int cellNumber = 0; cellNumber < 10; cellNumber++) {
XSSFCell cell = row.createCell(cellNumber);
cell.setCellValue(cellNumber);
}
}
FileOutputStream fileOutputStream = new FileOutputStream(Path + "大数据07.xls");//07 xlsx
workbook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("生成完毕");
long end = System.currentTimeMillis();
System.out.println((double)(end - begin)/1000);
}
可以写超过65536但是速度很慢。
优化：SXSSF
过程中会产生临时文件，默认100条记录被保存再内存中，若超过100条则最前面的数据被写入临时文件。通过new SXSSFWorkbook(数量)来修改默认保存记录数。
@Test
void testBigData07s() throws IOException {
long begin = System.currentTimeMillis();
SXSSFWorkbook workbook = new SXSSFWorkbook();
SXSSFSheet sheet = workbook.createSheet();
for (int rowNumber = 0; rowNumber <65537 ; rowNumber++) {
SXSSFRow row = sheet.createRow(rowNumber);
for (int cellNumber = 0; cellNumber < 10; cellNumber++) {
SXSSFCell cell = row.createCell(cellNumber);
cell.setCellValue(cellNumber);
}
}
FileOutputStream fileOutputStream = new FileOutputStream(Path + "大数据07.xls");//07 xlsx
workbook.write(fileOutputStream);
fileOutputStream.close();
// 清除临时文件
workbook.dispose();
System.out.println("生成完毕");
long end = System.currentTimeMillis();
System.out.println((double)(end - begin)/1000);
}
数据读取
读取时要特别注意单元格的数据类型，如果不一致会报错，可以先用typeof进行判断。
@Test
public void testRead03() throws IOException {
FileInputStream inputStream = new FileInputStream(Path + "大数据03.xls");
HSSFWorkbook workbook = new HSSFWorkbook(inputStream);
HSSFSheet sheet = workbook.getSheetAt(0);
HSSFRow row = sheet.getRow(9);
HSSFCell cell = row.getCell(9);
System.out.println(cell.getNumericCellValue());
//读取数字类型
//System.out.println(cell.getStringCellValue()); 读取字符串类型
}
读取不同类型
@Test
public void testCellType() throws IOException {
FileInputStream inputStream = new FileInputStream(Path + "2020.xlsx");
Workbook workbook = new XSSFWorkbook(inputStream);
Sheet sheet = workbook.getSheetAt(0);
Row rowTitle = sheet.getRow(1);
//读取标题
if(rowTitle!=null){
int cellCount = rowTitle.getPhysicalNumberOfCells();
for (int i = 0; i
计算公式：
@Test
public void testFormula() throws IOException {
FileInputStream inputStream = new FileInputStream(Path + "计算公式.xlsx");
Workbook workbook = new XSSFWorkbook(inputStream);
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(3);
Cell cell = row.getCell(0);
// 用于计算公式
Formulaevaluator evaluator = new XSSFFormulaevaluator((XSSFWorkbook) workbook);
CellType type = cell.getCellType();
switch (type){
case FORMULA:
String formula = cell.getCellFormula();
System.out.println(formula);
CellValue evaluate = evaluator.evaluate(cell);
System.out.println(evaluate.formatAsString());
}
}
EasyExcel
根据官方文档 *** 作https://www.yuque.com/easyexcel/doc/write
实体类
package cn.zjq;
import com.alibaba.excel.annotation.ExcelIgnore;
import com.alibaba.excel.annotation.ExcelProperty;
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
import java.util.Date;
@Getter
@Setter
@EqualsAndHashCode
public class DemoData {
@ExcelProperty("字符串标题")
private String string;
@ExcelProperty("日期标题")
private Date date;
@ExcelProperty("数字标题")
private Double doubleData;
@ExcelIgnore
private String ignore;
}
写入
package cn.zjq;
import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.util.ListUtils;
import org.junit.jupiter.api.Test;
import java.util.Date;
import java.util.List;
public class EasyExcelTests {
private static String Path = "D:/CODE/poi-easyEXCEL/";
private List data() {
List list = ListUtils.newArrayList();
for (int i = 0; i < 10; i++) {
DemoData data = new DemoData();
data.setString("字符串" + i);
data.setDate(new Date());
data.setDoubleData(0.56);
list.add(data);
}
return list;
}
@Test
public void simpleWrite() {
// 注意 simpleWrite在数据量不大的情况下可以使用（5000以内，具体也要看实际情况），数据量大参照 重复多次写入
// 写法1 JDK8+
// since: 3.0.0-beta1
String fileName =Path + "simpleWrite" + System.currentTimeMillis() + ".xlsx";
// 这里 需要指定写用哪个class去写，然后写到第一个sheet，名字为模板 然后文件流会自动关闭
// 如果这里想使用03 则 传入excelType参数即可
EasyExcel.write(fileName, DemoData.class)
.sheet("模板")//表的名字
.doWrite(data());
}
}
读取
虚拟的DAO层
import java.util.List;
public class DemoDAO {
public void save(List list) {
// 如果是mybatis,尽量别直接调用多次insert,自己写一个mapper里面新增一个方法batchInsert,所有数据一次性插入
}
}
监听器
package cn.zjq.eexcel;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.read.listener.ReadListener;
import com.alibaba.excel.util.ListUtils;
import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import java.util.List;
// 有个很重要的点 DemoDataListener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去
@Slf4j
public class DemoDataListener implements ReadListener {
private static final int BATCH_COUNT = 100;
private List cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
private DemoDAO demoDAO;
public DemoDataListener() {
// 这里是demo，所以随便new一个。实际使用如果到了spring,请使用下面的有参构造函数
demoDAO = new DemoDAO();
}
public DemoDataListener(DemoDAO demoDAO) {
this.demoDAO = demoDAO;
}
@Override
public void invoke(DemoData data, AnalysisContext context) {
System.out.println(JSON.toJSONString(data));
cachedDataList.add(data);
// 达到BATCH_COUNT了，需要去存储一次数据库，防止数据几万条数据在内存，容易OOM
if (cachedDataList.size() >= BATCH_COUNT) {
saveData();
// 存储完成清理 list
cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
}
}
@Override
public void doAfterAllAnalysed(AnalysisContext context) {
// 这里也要保存数据，确保最后遗留的数据也存储到数据库
saveData();
log.info("所有数据解析完成！");
}
private void saveData() {
log.info("{}条数据，开始存储数据库！", cachedDataList.size());
demoDAO.save(cachedDataList);
log.info("存储数据库成功！");
}
}
测试
@Test
public void simpleRead() {
// 写法1：JDK8+ ,不用额外写一个DemoDataListener
// since: 3.0.0-beta1
String fileName = Path + "simpleWrite1643442278838.xlsx";
// 这里 需要指定读用哪个class去读，然后读取第一个sheet 文件流会自动关闭
// 这里每次会读取3000条数据 然后返回过来 直接调用使用数据就行
EasyExcel.read(fileName, DemoData.class, new DemoDataListener()).sheet().doRead();
}
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