java - Excel 数据仅写入第一行 - java

Question

我已经编写了使用 java 将数据写入 Excel 的代码，但是，它不会增加 roe 值，导致第 1 行本身的数据被覆盖。我知道问题出在 rownum 计数增量。

import java.util.*;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.util.*; 
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.*;
import java.io.*;

public class ExcelWriter {
static int rownum;
@Test
public void ExcelWriters(Integer i, String CableName, String Count,
    String EndCableId, String FirstCableId) {
    rownum = i;
    HSSFWorkbook workbook = new HSSFWorkbook();
    HSSFSheet sheet = workbook.createSheet("WhileTrue");
    Map < Integer, Object[] > data = new HashMap < Integer, Object[] > (); {
        data.put(i, new Object[] {
            "Sr.no",
            "Cable",
            "Total Count",
            "EndCableId",
            "FirstCableId"
        });
        data.put(i, new Object[] {
            i,
            CableName,
            Count,
            EndCableId,
            FirstCableId
        });

        Set < Integer > keyset = data.keySet();

        for (Integer key: keyset) {
            HSSFRow row = sheet.createRow(rownum++);
            Object[] objArr = data.get(key);
            int cellnum = 0;
            for (Object obj: objArr) {
                HSSFCell cell = row.createCell(cellnum++);

                if (obj instanceof Date)
                    cell.setCellValue((Date) obj);
                else if (obj instanceof Boolean)
                    cell.setCellValue((Boolean) obj);
                else if (obj instanceof String)
                    cell.setCellValue((String) obj);
                else if (obj instanceof Double)
                    cell.setCellValue((Double) obj);
            }

        }

        try {
            FileOutputStream outputStream =

                new FileOutputStream((new File("FilePath")));
            workbook.write(outputStream);
            outputStream.close();
            System.out.println("Excel written Successfully");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

}

Answer 1

通过使用 data.put(i,new Object[]{...} 两次，映射仅保存给定键 i 的最后一个值，(即)您覆盖列的名称。

将第一个 put(i,YOUR_COL_NAMES); 更改为 put(0,YOUR_COL_NAMES);