REACTJS:如何使<th>只打印一次并与<td>正确对齐

class Table extends React.Component {
  render() {
    return (
      <table>
        <thead>
          <tr>
            <th>表头</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td>内容</td>
          </tr>
        </tbody>
      </table>
    );
  }
}

class Table extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      showHeader: true
    };
  }

  render() {
    return (
      <table>
        <thead>
          {this.state.showHeader && (
            <tr>
              <th>表头</th>
            </tr>
          )}
        </thead>
        <tbody>
          <tr>
            <td>内容</td>
          </tr>
        </tbody>
      </table>
    );
  }
}