原生input上传文件

            <input
              id="file"
              ref={(el) => {
                this.input = el;
              }}
              type="file"
              accept="image/*"
              onChange={this.HandleImageChange}
            ></input>

  HandleImageChange = (e) => {
    //处理图片
    const file = e.target.files[0];
    console.log(e, file);
    var reader = new FileReader();
    reader.onload = function (e) {
      // console.log(reader.result); //或者 e.target.result都是一样的，都是base64码
    };
    reader.readAsDataURL(file);
    var myHeaders = new Headers();
    myHeaders.append(
      "Authorization",
      `Bearer ${localStorage.getItem("token")}`
    );
    var formdata = new FormData();
    formdata.append(`${file.name}`, file);
    var requestOptions = {
      method: "POST",
      headers: myHeaders,
      body: formdata,
      redirect: "follow",
    };
    fetch(`${this.state.requestUrl}`, requestOptions)
      .then((response) => response.text())
      .then((result) => console.log(result))
      .catch((error) => console.log("error", error));
  };