在导入Excel的时候，如果文件比较大，行数很多，一行行读往往速度比较慢，为了加快导入速度，我们可以采用多线程的方式
话不多说直接上代码
首先是Controller
import com.sakura.base.service.ExcelService;
import com.sakura.common.api.ApiResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;@RestController
@RequestMapping("/excel")
public class ExcelController {@Autowiredprivate ExcelService excelService;@PostMapping("/import")public ApiResult<Boolean> importExcel(@ModelAttribute MultipartFile file) throws Exception {boolean flag = excelService.importExcel(file);return ApiResult.result(flag);}
}
然后Service
import org.springframework.web.multipart.MultipartFile;public interface ExcelService {boolean importExcel(MultipartFile file) throws Exception;}
ServiceImpl
import com.sakura.base.entity.User;
import com.sakura.base.mapper.UserMapper;
import com.sakura.base.service.ExcelService;
import lombok.extern.java.Log;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;@Service
@Log
public class ExcelServiceImpl implements ExcelService {@Autowiredprivate UserMapper userMapper;@Overridepublic boolean importExcel(MultipartFile file) throws Exception {// 文件为空这些校验大家自己加，这里只是做一个示例// 每次处理的数据量，大家可以自己调整，比如每次处理1000条int batchSize = 5;// 最大线程数，大家可以自己调整，根据自己服务器性能来调整int maxThreads = 3;// 创建一个线程池并设置最大线程数ExecutorService executorService = Executors.newFixedThreadPool(maxThreads);Workbook workbook = null;try {workbook = new XSSFWorkbook(file.getInputStream());// 获取第一页Sheet sheet = workbook.getSheetAt(0);// 获取总行数int rowCount = sheet.getLastRowNum();// 第0行一般为表头，从第一行开始int startRow = 1;// 结束行，Math.min用来比较两个数的大小，取最小值int endRow = Math.min(batchSize, rowCount);while (startRow <= rowCount) {// 提交任务到线程池executorService.execute(new ExcelRowProcessorTask(sheet, startRow, endRow));// 下一批数据的起始行startRow = endRow + 1;// 下一批数据的结束行endRow = Math.min(startRow + batchSize - 1, rowCount);}// 关闭线程池executorService.shutdown();} catch (Exception e) {e.printStackTrace();} finally {// 关闭流if (workbook != null) {try {workbook.close();} catch (IOException e) {e.printStackTrace();}}}return true;}private class ExcelRowProcessorTask implements Runnable {private final Sheet sheet;private final int startRow;private final int endRow;public ExcelRowProcessorTask(Sheet sheet, int startRow, int endRow) {this.sheet = sheet;this.startRow = startRow;this.endRow = endRow;}@Overridepublic void run() {// _________________________________________// 测试用，模拟处理数据的耗时，实际应用删除try {Thread.sleep(2000);} catch (InterruptedException e) {throw new RuntimeException(e);}// _________________________________________for (int i = startRow; i <= endRow; i++) {Row row = sheet.getRow(i);if (row != null) {Cell nameCell = row.getCell(0); // 第一列Cell phoneCell = row.getCell(1); // 第二列nameCell.setCellType(CellType.STRING);String name = nameCell.getStringCellValue();phoneCell.setCellType(CellType.STRING);String phoneNumber = phoneCell.getStringCellValue();User user = new User();user.setName(name);user.setPhoneNumber(phoneNumber);userMapper.insert(user);}}}}
}
实体类User就不贴了没啥好说的
还有就是poi的jar包
<dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId><version>3.15</version></dependency><dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>3.15</version></dependency>
用postman验证上面的代码
可以看下数据库的数据，因为我限制了每次处理的数据为5条，同时最多有3个线程，所以可以看到同一时间段导进去的数据为15条
上面这个还有一个问题就是主线程不会等数据导入完就会返回，如果你需要主线程等待数据导入完可以加上下面这行代码
executorService.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS); // 等待所有任务执行完毕 Long.MAX_VALUE为超时时间，可以自由设置
就放在关闭线程池后面就可以了
有想看下怎么用多线程导出Excel的移步 Java多线程导出Excel示例
