java mysql插入空列

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class InsertNullExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String user = "username";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            String sql = "INSERT INTO users (username, email, age) VALUES (?, ?, ?)";
            try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
                pstmt.setString(1, "john_doe");
                pstmt.setString(2, null); // 允许email列为空
                pstmt.setInt(3, 30);

                int rowsInserted = pstmt.executeUpdate();
                if (rowsInserted > 0) {
                    System.out.println("A new user was inserted successfully!");
                }
            }
        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
    }
}