如何在react中重新渲染组件？

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  handleClick() {
    this.setState({ count: this.state.count + 1 });
  }

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => this.handleClick()}>Increment</button>
      </div>
    );
  }
}

class MyComponent extends React.Component {
  handleClick() {
    this.forceUpdate();
  }

  render() {
    return (
      <div>
        <p>Component will be re-rendered</p>
        <button onClick={() => this.handleClick()}>Re-render</button>
      </div>
    );
  }
}

class MyComponent extends React.Component {
  handleClick() {
    ReactDOM.render(<NewComponent />, document.getElementById('root'));
  }

  render() {
    return (
      <div>
        <p>Click the button to re-render</p>
        <button onClick={() => this.handleClick()}>Re-render</button>
      </div>
    );
  }
}