getQRCode() {
    var that = this;
    wx.request({
      url: 'http://localhost:8080/getQRCode?ID=' + '13',
      header: {
        'content-type': 'application/json'
      },
      method: 'POST',
      responseType: 'arraybuffer',//将原本按文本解析修改为arraybuffer
      success(res) {
        that.setData({
          getQRCode: wx.arrayBufferToBase64(res.data)
        })
        console.log(that.data.getQRCode1)
      }
    })
  },

<button  class="btn1" type="primary" bindtap="getQRCode">生成携带参数的二维码</button><!--绿色样式-->
<view>二维码：<image src="data:image/png;base64,{{getQRCode}}"  style="width: 50vw; height: 20vh;"></image></view>

  /**
   * 页面的初始数据
   */
  data: {
    getQRCode: "",
  },