ant-design/components/upload/demo/avatar.md

---
order: 1
title:
  zh-CN: 用户头像
  en-US: Avatar
---

## zh-CN

点击上传用户头像，并使用 `beforeUpload` 限制用户上传的图片格式和大小。

> `beforeUpload` 的返回值可以是一个 Promise 以支持异步处理，如服务端校验等：[示例](http://react-component.github.io/upload/examples/beforeUpload.html)。

## en-US

Click to upload user's avatar, and validate size and format of picture with `beforeUpload`.

> The return value of function `beforeUpload` can be a Promise to check asynchronously. [demo](http://react-component.github.io/upload/examples/beforeUpload.html)

````jsx
import { Upload, Icon, message } from 'antd';

function getBase64(img, callback) {
  const reader = new FileReader();
  reader.addEventListener('load', () => callback(reader.result));
  reader.readAsDataURL(img);
}

function beforeUpload(file) {
  const isJPG = file.type === 'image/jpeg';
  if (!isJPG) {
    message.error('You can only upload JPG file!');
  }
  const isLt2M = file.size / 1024 / 1024 < 2;
  if (!isLt2M) {
    message.error('Image must smaller than 2MB!');
  }
  return isJPG && isLt2M;
}

class Avatar extends React.Component {
  state = {
    loading: false,
  };

  handleChange = (info) => {
    if (info.file.status === 'uploading') {
      this.setState({ loading: true });
      return;
    }
    if (info.file.status === 'done') {
      // Get this url from response in real world.
      getBase64(info.file.originFileObj, imageUrl => this.setState({
        imageUrl,
        loading: false,
      }));
    }
  }

  render() {
    const uploadButton = (
      <div>
        <Icon type={this.state.loading ? 'loading' : 'plus'} />
        <div className="ant-upload-text">Upload</div>
      </div>
    );
    const imageUrl = this.state.imageUrl;
    return (
      <Upload
        name="avatar"
        listType="picture-card"
        className="avatar-uploader"
        showUploadList={false}
        action="//jsonplaceholder.typicode.com/posts/"
        beforeUpload={beforeUpload}
        onChange={this.handleChange}
      >
        {imageUrl ? <img src={imageUrl} alt="avatar" /> : uploadButton}
      </Upload>
    );
  }
}

ReactDOM.render(<Avatar />, mountNode);
````

````css
.avatar-uploader > .ant-upload {
  width: 128px;
  height: 128px;
}
````