一、文件流展示

<image src="{{codeImg}}" mode="widthFix" ></image>
wx.request({
            url: url,
            data:data,
            header: {
              'content-type': 'application/json;charset=utf-8',
            },
            method: "get",
            responseType: "arraybuffer",
            success(res) {                
              let codeImg ="data:image/png;base64," + wx.arrayBufferToBase64(res.data)
                that.setData({
                    codeImg
                })                
            }
        }) 

一、base64展示

<image  src="data:image/png;base64,{{base64Data}}"></image>