java数据库更新操作

try (Connection conn = DriverManager.getConnection(url, username, password)) {
    String sql = "UPDATE users SET age = ? WHERE id = ?";
    try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
        pstmt.setInt(1, 30);
        pstmt.setInt(2, 1);
        int affectedRows = pstmt.executeUpdate();
        if (affectedRows == 0) {
            System.out.println("No rows updated.");
        } else {
            System.out.println("Rows updated: " + affectedRows);
        }
    }
} catch (SQLException e) {
    e.printStackTrace();
}

try (Connection conn = DriverManager.getConnection(url, username, password)) {
    String sql = "UPDATE users SET age = ? WHERE id = ?";
    try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
        pstmt.setInt(1, 30);
        pstmt.setInt(2, 1);
        pstmt.executeUpdate();
    }
} catch (SQLException e) {
    System.out.println("SQL Exception: " + e.getMessage());
}