一、起步

一、创建react-app

# npm install -g create-react-app

npx create-react-app my-app
cd my-app
npm start

二、删除src下多余的文件-启动hello world

src
   index.js
   App.js
//index.js
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
ReactDOM.render(<App />, document.getElementById('root'));
//App.js
import React from 'react';
class App extends React.Component{
    render(){
        return (<div>hello world</div>)
    }
}

三、读取服务器上的数据

3-1 安装axios

npm i axios -S

3-2 在state中去定义变量装载从接口取得的数据

constructor(props) {
    super(props);
    this.state = {
      musics: []
    }
  }

3-3 ComponentDidMount发起http请求

import axios from 'axios'
class App extends React.Component{
    ....
    componentDidMount() {
    var url = "http://192.168.14.49:5000/top/playlist?cat=华语"
    axios.get(url).then(res => {
      console.log(res.data.playlists)
      this.setState({
        musics: res.data.playlists
      })
    })
  }
}

3-4 render函数中渲染数据

class App extends React.Component{
    ...
   render() {
    return (
      <div>
        <div>
          {this.state.musics.map(item => {
            return (<div key={item.id}>
              <img src={item.coverImgUrl} alt={item.name} />
              <p> {item.name}</p>
            </div>)
          })}
        </div>
      </div>
    )
  }
}