Can not setState on Websocket.onmessage

// WebSocket连接和onmessage事件处理程序
const socket = new WebSocket('wss://example.com/socket');

socket.onmessage = function(event) {
  // 触发自定义事件
  document.dispatchEvent(new CustomEvent('websocketMessage', { detail: event.data }));
};

// React组件中监听自定义事件并更新状态
class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      message: ''
    };
  }

  componentDidMount() {
    // 监听自定义事件
    document.addEventListener('websocketMessage', this.handleWebsocketMessage);
  }

  componentWillUnmount() {
    // 移除事件监听
    document.removeEventListener('websocketMessage', this.handleWebsocketMessage);
  }

  handleWebsocketMessage = (event) => {
    // 更新状态
    this.setState({ message: event.detail });
  }

  render() {
    return (
      <div>
        <p>{this.state.message}</p>
      </div>
    );
  }
}