Question

我有一个字符串的ArrayList非常庞大（大约超过500k和更多的项目）。有没有可能加快将此数组写入excel文件？现在它需要一段时间，我不知道我是否做了我能做的一切（也许这是.get方法的问题？）。请参考以下代码（请不要为详细信息付费 - 此类仅为测试目的而创建）：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
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.apache.poi.xssf.usermodel.XSSFWorkbook;

public class Tests {

private static final String ADDRESS = "./result/file.xlsx";

public static void readAndWriteAData(int counterOfExecutions, List<String> listOfResults) throws IOException{

    File file = new File(ADDRESS);
    if(file.exists()&&!file.isDirectory()){
        file.delete();
    }

    @SuppressWarnings("resource")
    Workbook wb = new XSSFWorkbook();

    FileOutputStream fileOut = new FileOutputStream(ADDRESS);
    wb.write(fileOut);
    fileOut.close();

    Sheet sheet = wb.createSheet("1");
    Row row;
    Cell cell;
    int add = 0;
    System.out.println("Start of filling excel file");

    for(int i=0; i<counterOfExecutions;i++){
        row = sheet.createRow(i);

        for(int j=0; j<5; j++){
            cell = row.createCell(j);
            cell.setCellValue(listOfResults.get(j+add));
        }

        add+=5;
    }


    FileOutputStream fileOutputSecond = new FileOutputStream(file);
    wb.write(fileOutputSecond);
    fileOutputSecond.close();
    System.out.println("File "+ADDRESS+" has been created.");
}

public static void main(String[] args) throws IOException {

    System.out.println("Start of creating ArrayList");
    List<String> lista = new ArrayList<>();
    for(int i = 1 ; i<550000;i++){
        lista.add("nic "+i);
    }
    System.out.println("ArrayList has been filled");


    readAndWriteAData(100999, lista);
    System.out.println("The End");

}

}

提前感谢任何提示！：）

Answer 1

请尝试使用SXSSFWorkbook。为了更好地使用它会更有效率尝试查看Apache POI 3.8 API

Answer 2

看看示例

how-to-read-write-xlsx-file-in-java-apache-poi-example

Answer 3

请参阅以下

How to speed up excel reading/writing

可能这解决了同样的问题;记录器配置对我有用。

使用Apache POI写入Excel文件来自字符串ArrayList

3 个答案: