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

  handleChange(event) {
    this.setState({ inputValue: event.target.value });
  }

  render() {
    return (
      <input
        type="text"
        value={this.state.inputValue}
        onChange={this.handleChange.bind(this)}
      />
    );
  }
}

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.inputRef = React.createRef();
  }

  handleClick() {
    const inputValue = this.inputRef.current.value;
    // 处理输入字段的值
  }

  render() {
    return (
      <div>
        <input type="text" ref={this.inputRef} />
        <button onClick={this.handleClick.bind(this)}>修改</button>
      </div>
    );
  }
}