Question

我有一个场景，我想写一个值对象列表，如：

public class RequestHandlerVo {

private String userSoeID;
private String email;
private String firstName;
private String lastName;
private String publicationReceived;
private String sourceOfUnsubscribe;
private String senderEmail;
private String receivedDateFrom;
private String receivedDateTo;
private String apiName;
private String updatedBy;
private String updatedOn;
private String action;
}

在不使用此逻辑的情况下进入excelsheet：

Set<Integer> keyset = hashmap.keySet();
    InputStream inp = new FileInputStream( new File(path));
    FileOutputStream out = new FileOutputStream( new File(path));
    int rownum = 1;
    int cellnum = 0;

    initializeExcelFile(hashmap,path);

    workbook = new XSSFWorkbook(inp);

    XSSFSheet sheet = workbook.getSheetAt(0);

    for(Integer key : keyset){
        List<String> nameList = hashmap.get(key);
        for(String s : nameList){
            XSSFRow row = sheet.getRow(rownum++);
            Cell cell = row.getCell(cellnum);
            if(null!=cell){
                cell.setCellValue(s);
            }
        }
        cellnum++;
        rownum=1;
    }

    workbook.write(out);

因为我有成千上万的记录，这个逻辑导致我超过100k次迭代。在excel文件中写入1035条记录需要92秒。

我经历过： this，Write data into Excel sheet java和How list has map values write to excel file using Apache poi

但没有得到解决方案。

Answer 1

如果你对CSV或其他文件格式没问题，你可以试试这个。下面的示例使用单行代码从ArrayList写入CSV文件。

您可以根据输入源类型对其进行修改。

ArrayList<String> data = new ArrayList<String>();
// add data to arrray list

Path out = Paths.get("filename.csv");
Files.write(out, data, Charset.defaultCharset());

如何在不迭代每一列的情况下将值对象列表直接写入Excel文件？

1 个答案: