我的目标是将数据从 excel 文件上传到 postgreSQL，该文件的列数可能是随机的

Question

示例：我的 excel 包含 10 列，而我的数据库有 15 列，即使有 5 列为空，它仍会上传。

我使用的代码可以上传 excel 但是当单元格为空时会出错。

Tools/language 我正在使用（我认为它们在这里都不重要）：xhtml、Java、Tomcat、PostgreSQl、Primefaces

在此先感谢您的帮助。

这是我使用的代码：

    public void upload() throws IOException{

    String host="localhost";
    String port="5432";
    String db_name="postgres";
    String username="postgres";
    String password="postgres";

    int max = 1000;
    int min = 0;
    String dir="C:\Users\User\Desktop\book1.xlsx";

    int batchSize = 20;
    Connection connection = null;

    try {
        long start = System.currentTimeMillis();

        FileInputStream inputStream = new FileInputStream(dir);

        Workbook workbook = new XSSFWorkbook(inputStream);

        Sheet firstSheet = workbook.getSheetAt(0);
        Iterator<Row> rowIterator = firstSheet.iterator();

        try {
            Class.forName("org.postgresql.Driver");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        connection = DriverManager.getConnection("jdbc:postgresql://"+host+":"+port+"/"+db_name+"", ""+username+"", ""+password+"");
        connection.setAutoCommit(false);

        String sql = "INSERT INTO survey.tabledata (id,col1,col2,col3,col4,col5,col6,col7,col8,col9,col10,surveyid) VALUES (?,?,?,?,?,?,?,?,?,?,?,?)";
        PreparedStatement statement = connection.prepareStatement(sql);    

        int count = 0;
    
        //rowIterator.next(); // skip the header row

        while (rowIterator.hasNext()) {
            Row nextRow = rowIterator.next();
            Iterator<Cell> cellIterator = nextRow.cellIterator();

            while (cellIterator.hasNext()) {
            
                Cell nextCell = cellIterator.next();

                int columnIndex = nextCell.getColumnIndex();

                switch (columnIndex) {

                case 0:
                    int col1 = (int) nextCell.getNumericCellValue(); 
                    statement.setInt(1,col1);
                    break;

                case 1:

                    String col2 = nextCell.getStringCellValue();
                    statement.setString(2, col2);
                    break;

                case 2:

                    String col3 = nextCell.getStringCellValue();
                    statement.setString(3, col3);
                    break;

                case 3:

                    String col4 = nextCell.getStringCellValue();
                    statement.setString(4, col4);
                    break;

                case 4:

                    String col5 = nextCell.getStringCellValue();
                    statement.setString(5, col5);
                    break;

                case 5:

                    String col6 = nextCell.getStringCellValue();
                    statement.setString(6, col6);
                    break;

                case 6:

                    String col7 = nextCell.getStringCellValue();
                    statement.setString(7, col7);
                    break;
                case 7:

                    String col8 = nextCell.getStringCellValue();
                    statement.setString(8, col8);
                    break;
                case 8:

                    String col9 = nextCell.getStringCellValue();
                    statement.setString(9, col9);
                    break;

                case 9:

                    String col10 = nextCell.getStringCellValue();
                    statement.setString(10, col10);
                    break;

                case 10:
                    String col11 = nextCell.getStringCellValue();
                    statement.setString(11, col11);
                    break;

                case 11:
                    int col12 = (int) nextCell.getNumericCellValue();
                    statement.setInt(12,col12);
                    break;

                }
            }
            statement.addBatch();

            if (count % batchSize == 0) {
                statement.executeBatch();
            }              
        }
        // workbook.close();
        // execute the remaining queries
        statement.executeBatch();

        connection.commit();
        connection.close();

        long end = System.currentTimeMillis();
        System.out.printf("Import done in %d ms\n", (end - start));

    } catch (IOException ex1) {
        System.out.println("Error reading file");
        ex1.printStackTrace();
    } catch (SQLException ex2) {
        System.out.println("Database error");
        ex2.printStackTrace();
    }
}

Answer 1

它会给你一个错误，因为你正在转换一个 null 或空值。

Answer 2

即使您的错误消息不在您的问题描述中，我猜您的数据库中有一个 null 异常。

你可以这样解决：

String col = nextCell.getStringCellValue();
if(col == null)
{
    col = "";
}

statement.setString(1, col);

我的目标是将数据从 excel 文件上传到 postgreSQL，该文件的列数可能是随机的

My goal is to upload data from an excel file that may have random number of columns to postgreSQL

java

postgresql

excel

xhtml

primefaces