buf2str(buffer) {
      let  encodedString = String.fromCodePoint.apply(null, new Uint8Array(buffer));
      let decodedString = decodeURIComponent(escape(encodedString));//没有这一步中文会乱码
      console.log(decodedString);
      return decodedString
　　时间紧迫，请看代码。亲测有效