Google Maps Javascript API、标记和折线无法在React.js应用程序上一起显示的问题

import React, { Component } from 'react';

class MapComponent extends Component {
  componentDidMount() {
    // 初始化地图
    const map = new window.google.maps.Map(document.getElementById('map'), {
      center: { lat: 37.7749, lng: -122.4194 },
      zoom: 8
    });

    // 添加标记
    const marker = new window.google.maps.Marker({
      position: { lat: 37.7749, lng: -122.4194 },
      map: map,
      title: 'San Francisco'
    });

    // 添加折线
    const line = new window.google.maps.Polyline({
      path: [
        { lat: 37.7749, lng: -122.4194 },
        { lat: 37.3382, lng: -121.8863 }
      ],
      map: map
    });
  }

  render() {
    return <div id="map" style={{ width: '100%', height: '400px' }}></div>;
  }
}

export default MapComponent;