使用state

return (
    

        大家好我是{this.state.name}今年{this.state.age}岁了
    
  );

完整代码

import React, { Component } from 'react';

class App extends Component { 
  constructor() {  
    super();  
    this.state={name:"mumu",age:18}
  }
  render() {
    return (
      

          大家好我是{this.state.name}今年{this.state.age}岁了
      
    );
  }
}

export default App;