jdbc无法写入mysql数据库

String url = "jdbc:mysql://localhost:3306/mydatabase";
String user = "username";
String password = "password";
try (Connection conn = DriverManager.getConnection(url, user, password)) {
    // 连接成功
} catch (SQLException e) {
    e.printStackTrace();
}

String sql = "INSERT INTO mytable (column1, column2) VALUES (?, ?)";
try (Connection conn = DriverManager.getConnection(url, user, password);
     PreparedStatement pstmt = conn.prepareStatement(sql)) {
    pstmt.setString(1, "value1");
    pstmt.setString(2, "value2");
    int rowsInserted = pstmt.executeUpdate();
    if (rowsInserted > 0) {
        System.out.println("数据插入成功");
    }
} catch (SQLException e) {
    e.printStackTrace();
}

Class.forName("com.mysql.cj.jdbc.Driver");