超大excel文件读,避免内存溢出
excel40M+,但是用传统的读取excel方法,会报内存溢出的错误。
所以采用了下面的方式,能解决此问题:
maven依赖
<dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId><version>4.0.0</version> </dependency> <dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>4.0.0</version> </dependency> <dependency><groupId>org.apache.poi</groupId><artifactId>poi-scratchpad</artifactId><version>4.0.0</version> </dependency><!-- 读取大量excel数据时使用 --> <dependency><groupId>com.monitorjbl</groupId><artifactId>xlsx-streamer</artifactId><version>2.1.0</version> </dependency>
代码:
import com.monitorjbl.xlsx.StreamingReader;
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 java.io.FileInputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;public class Main {public static void main(String[] args){try{FileInputStream fis = new FileInputStream("D:\\d\\2023财年\\新疆\\a.xlsx");Workbook wk = StreamingReader.builder().rowCacheSize(100) //缓存到内存中的行数,默认是10.bufferSize(4096) //读取资源时,缓存到内存的字节大小,默认是1024.open(fis); //打开资源,必须,可以是InputStream或者是File,注意:只能打开XLSX格式的文件int sheetNums = wk.getNumberOfSheets();System.out.println(sheetNums);List<String> sheets = new ArrayList<>();for(int i = 0 ; i < sheetNums;i ++){Sheet sheet = wk.getSheetAt(i);String sheetName = wk.getSheetName(i);//遍历所有的行for (Row row : sheet) {StringBuilder sb = new StringBuilder();//遍历所有的列for (Cell cell : row) {sb.append(cell.getStringCellValue().replaceAll("\\s+", "").toUpperCase(Locale.ROOT) + ",");}if(sb.toString().contains("模型名称")){sheets.add(sb.toString().replaceAll("模型名称:", "").replaceAll("模型名称:", "").replaceAll("表名:", ","));}}}for(String data: sheets){System.out.println(data);}}catch (Exception e){e.printStackTrace();}}
}